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Murphy CM, Friedrich LM, Strawn LK, Danyluk MD. Salmonella and Listeria monocytogenes survival on Field Packed Cantaloupe Contact Surfaces. J Food Prot 2024:100299. [PMID: 38734412 DOI: 10.1016/j.jfp.2024.100299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/29/2024] [Accepted: 05/06/2024] [Indexed: 05/13/2024]
Abstract
Field-packing of cantaloupes involves numerous food contact surfaces that can contamination melons with foodborne pathogens; the soil on these surfaces increases throughout the harvest day. Data is lacking on the cross-contamination risk from contaminated food contact surfaces under the dry conditions typical of cantaloupe field-packing operations. This study sought to evaluate the survival of Salmonella and Listeria monocytogenes on cantaloupe field-pack food contact surfaces using both a wet and dry inoculum to provide insights into managing foodborne pathogen contamination risks. Five clean or fouled materials (cotton gloves, nitrile gloves, rubber gloves, cotton rags, and stainless steel) were inoculated with a cocktail of either Salmonella or L. monocytogenes. A wet inoculum was spot inoculated (100 µL) onto coupons. A dry inoculum was prepared by mixing wet inoculum with 100 g of sterile sand, and shaking the coupons with the inoculated sand for 2min. Coupons were held at 35°C (35% RH) and enumerated at 0, 2, 4, 6 and 8 h. Significant differences in pathogen concentrations over time were calculated and the GInaFiT add-in tool for Excel was used to build Log-linear, Weibull, and Biphasic die-off models. Depending on the material type, coupon condition, and inoculum type, Salmonella and L. monocytogenes reductions over 8 h ranged from 0.3-3.3 and -0.4-4.2 log10 CFU/coupon, respectively. For all material types, Salmonella reductions were highest on wet-inoculated clean coupons; L. monocytogenes varied by material type. Weibull and biphasic models were a better fit of respective pathogen die-off curves than linear models. Overall, faster die-off rates were seen for wet inoculated and clean materials. Since pathogen populations remained viable over the study duration and both inoculum type and coupon condition impacted survival, frequent sanitation or replacement of food contact surfaces during the operational day is needed to reduce the risk of cross-contamination.
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Affiliation(s)
- Claire M Murphy
- School of Food Science, Washington State University - Irrigated Agriculture Research and Extension Center, Prosser, WA, USA
| | - Loretta M Friedrich
- Department of Food Science, University of Florida - Citrus Research and Education Center, Lake Alfred, FL, USA
| | - Laura K Strawn
- Department of Food Science and Technology, Virginia Tech, Blacksburg, VA, USA
| | - Michelle D Danyluk
- Department of Food Science, University of Florida - Citrus Research and Education Center, Lake Alfred, FL, USA
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2
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Thomas GA, Paradell Gil T, Müller CT, Rogers HJ, Berger CN. From field to plate: How do bacterial enteric pathogens interact with ready-to-eat fruit and vegetables, causing disease outbreaks? Food Microbiol 2024; 117:104389. [PMID: 37919001 DOI: 10.1016/j.fm.2023.104389] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 09/11/2023] [Accepted: 09/17/2023] [Indexed: 11/04/2023]
Abstract
Ready-to-eat fruit and vegetables are a convenient source of nutrients and fibre for consumers, and are generally safe to eat, but are vulnerable to contamination with human enteric bacterial pathogens. Over the last decade, Salmonella spp., pathogenic Escherichia coli, and Listeria monocytogenes have been linked to most of the bacterial outbreaks of foodborne illness associated with fresh produce. The origins of these outbreaks have been traced to multiple sources of contamination from pre-harvest (soil, seeds, irrigation water, domestic and wild animal faecal matter) or post-harvest operations (storage, preparation and packaging). These pathogens have developed multiple processes for successful attachment, survival and colonization conferring them the ability to adapt to multiple environments. However, these processes differ across bacterial strains from the same species, and across different plant species or cultivars. In a competitive environment, additional risk factors are the plant microbiome phyllosphere and the plant responses; both factors directly modulate the survival of the pathogens on the leaf's surface. Understanding the mechanisms involved in bacterial attachment to, colonization of, and proliferation, on fresh produce and the role of the plant in resisting bacterial contamination is therefore crucial to reducing future outbreaks.
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Affiliation(s)
- Gareth A Thomas
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Teresa Paradell Gil
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Carsten T Müller
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Hilary J Rogers
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Cedric N Berger
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK.
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3
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Saha J, Topalcengiz Z, Sharma V, Friedrich LM, Danyluk MD. Fate and Growth Kinetics of Salmonella and Listeria monocytogenes on Mangoes During Storage. J Food Prot 2023; 86:100151. [PMID: 37634809 DOI: 10.1016/j.jfp.2023.100151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 08/18/2023] [Accepted: 08/22/2023] [Indexed: 08/29/2023]
Abstract
Imported mangoes have been linked to outbreaks of salmonellosis in the USA. The purpose of this research was to evaluate the persistence and growth kinetics of Salmonella and Listeria monocytogenes on the intact surface of whole 'Ataulfo', 'Kent', and 'Tommy Atkins' mangoes stored at three different temperatures. L. monocytogenes was also evaluated on fresh-cut 'Tommy Atkins' mangoes stored at 4, 12, 20 ± 2°C. Whole mangoes were spot inoculated with rifampicin-resistant pathogen cocktails (6 log CFU/mango) onto the midsection of whole fruit (n = 6). Fruit was stored at 12, 20, or 30 ± 2°C and sampled for up to 28 days. The specific growth rates derived from DMFit models as a function of time were used to develop secondary models. On 'Kent' mangoes, Salmonella had a population increase from 0.3 to 1.1 log CFU/mango with a linear growth rate of ∼0.004, 0.01, and 0.06 log CFU/mango/h at 12, 20, and 30°C, respectively. At 20 and 30°C, Salmonella growth rates were significantly higher than 12°C (P < 0.05). No clear Salmonella growth trend was observed; populations decreased up to 1.6 log CFU/mango on 'Tommy Atkins' and 'Ataulfo' at 12°C. Populations of L. monocytogenes on whole and fresh-cut mangoes declined regardless of temperature and storage period. Food safety during storage should be the top priority for fresh-cut tropical fruit processors.
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Affiliation(s)
- Joyjit Saha
- Department of Food Science and Human Nutrition, Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, USA
| | - Zeynal Topalcengiz
- Department of Food Engineering, Faculty of Engineering and Architecture, Muş Alparslan University, Muş 49250, Turkey; Department of Food Science, Center for Food Safety, University of Arkansas System Division of Agriculture, Fayetteville, AR 72704, USA
| | - Vijendra Sharma
- Department of Food Science and Human Nutrition, Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, USA
| | - Loretta M Friedrich
- Department of Food Science and Human Nutrition, Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, USA
| | - Michelle D Danyluk
- Department of Food Science and Human Nutrition, Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, USA.
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4
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Rothwell JG, Hong J, Morrison SJ, Vyas HKN, Xia B, Mai-Prochnow A, McConchie R, Phan-Thien KY, Cullen PJ, Carter DA. An Effective Sanitizer for Fresh Produce Production: In Situ Plasma-Activated Water Treatment Inactivates Pathogenic Bacteria and Maintains the Quality of Cucurbit Fruit. Microbiol Spectr 2023; 11:e0003423. [PMID: 37428084 PMCID: PMC10434273 DOI: 10.1128/spectrum.00034-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 06/18/2023] [Indexed: 07/11/2023] Open
Abstract
The effect of plasma-activated water (PAW) generated with a dielectric barrier discharge diffusor (DBDD) system on microbial load and organoleptic quality of cucamelons was investigated and compared to the established sanitizer, sodium hypochlorite (NaOCl). Pathogenic serotypes of Escherichia coli, Salmonella enterica, and Listeria monocytogenes were inoculated onto the surface of cucamelons (6.5 log CFU g-1) and into the wash water (6 log CFU mL-1). PAW treatment involved 2 min in situ with water activated at 1,500 Hz and 120 V and air as the feed gas; NaOCl treatment was a wash with 100 ppm total chlorine; control treatment was a wash with tap water. PAW treatment produced a 3-log CFU g-1 reduction of pathogens on the cucamelon surface without negatively impacting quality or shelf life. NaOCl treatment reduced the pathogenic bacteria on the cucamelon surface by 3 to 4 log CFU g-1; however, this treatment also reduced fruit shelf life and quality. Both systems reduced 6-log CFU mL-1 pathogens in the wash water to below detectable limits. The critical role of superoxide anion radical (·O2-) in the antimicrobial power of DBDD-PAW was demonstrated through a Tiron scavenger assay, and chemistry modeling confirmed that ·O2- generation readily occurs in DBDD-PAW generated with the employed settings. Modeling of the physical forces produced during plasma treatment showed that bacteria likely experience strong local electric fields and polarization. We hypothesize that these physical effects synergize with reactive chemical species to produce the acute antimicrobial activity seen with the in situ PAW system. IMPORTANCE Plasma-activated water (PAW) is an emerging sanitizer in the fresh food industry, where food safety must be achieved without a thermal kill step. Here, we demonstrate PAW generated in situ to be a competitive sanitizer technology, providing a significant reduction of pathogenic and spoilage microorganisms while maintaining the quality and shelf life of the produce item. Our experimental results are supported by modeling of the plasma chemistry and applied physical forces, which show that the system can generate highly reactive ·O2- and strong electric fields that combine to produce potent antimicrobial power. In situ PAW has promise in industrial applications as it requires only low power (12 W), tap water, and air. Moreover, it does not produce toxic by-products or hazardous effluent waste, making it a sustainable solution for fresh food safety.
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Affiliation(s)
- Joanna G. Rothwell
- ARC Training Centre for Food Safety in the Fresh Produce Industry, School of Life and Environmental Sciences, Faculty of Science, Sydney Institute of Agriculture, The University of Sydney, Sydney, New South Wales, Australia
| | - Jungmi Hong
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, New South Wales, Australia
| | - Stuart J. Morrison
- Department of Agricultural and Resource Economics, University of California, Davis, California, USA
| | - Heema Kumari Nilesh Vyas
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, New South Wales, Australia
- Sydney Institute of Infectious Diseases, The University of Sydney, Sydney, New South Wales, Australia
| | - Binbin Xia
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, New South Wales, Australia
| | - Anne Mai-Prochnow
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, New South Wales, Australia
| | - Robyn McConchie
- ARC Training Centre for Food Safety in the Fresh Produce Industry, School of Life and Environmental Sciences, Faculty of Science, Sydney Institute of Agriculture, The University of Sydney, Sydney, New South Wales, Australia
| | - Kim-Yen Phan-Thien
- ARC Training Centre for Food Safety in the Fresh Produce Industry, School of Life and Environmental Sciences, Faculty of Science, Sydney Institute of Agriculture, The University of Sydney, Sydney, New South Wales, Australia
| | - Patrick J. Cullen
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, New South Wales, Australia
| | - Dee A. Carter
- ARC Training Centre for Food Safety in the Fresh Produce Industry, School of Life and Environmental Sciences, Faculty of Science, Sydney Institute of Agriculture, The University of Sydney, Sydney, New South Wales, Australia
- Sydney Institute of Infectious Diseases, The University of Sydney, Sydney, New South Wales, Australia
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5
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Moreira J, Mera E, Singh Chhetri V, King JM, Gentimis T, Adhikari A. Effect of storage temperature and produce type on the survival or growth of Listeria monocytogenes on peeled rinds and fresh-cut produce. Front Microbiol 2023; 14:1151819. [PMID: 37396364 PMCID: PMC10313384 DOI: 10.3389/fmicb.2023.1151819] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 05/30/2023] [Indexed: 07/04/2023] Open
Abstract
Whole and fresh-cut produce are minimally processed and susceptible to microbial contamination. This study evaluated the survival or growth of L. monocytogenes on peeled rinds, and fresh-cut produce at different storage temperatures. Fresh-cut fruits and vegetables, including cantaloupe, watermelon, pear, papaya, pineapple, broccoli, cauliflower, lettuce, bell pepper, and kale (25 g pieces) were spot inoculated with 4 log CFU/g of L. monocytogenes and stored at 4 or 13°C for 6 days. Cantaloupe and bell pepper rind disks (20 cm2), mimicking whole produce were inoculated with low inoculum level (4 log CFU/mL) and high inoculum level (6 log CFU/mL) and stored at 24°C up to 8 days and 4°C up to 14 days, respectively. L. monocytogenes counts on fresh-cut pear samples stored at 4°C increased significantly by 0.27 log CFU/g. However, Listeria levels on kale (day 4), cauliflower (day 6), and broccoli (day 2) were significantly reduced by 0.73, 1.18, and 0.80 log CFU/g, respectively, at 4°C. At 13°C, the bacterial counts increased significantly after a day of storage on fresh-cut watermelons (increasing by 1.10 log CFU/g) and cantaloupes (increasing by 1.52 log CFU/g). Similar increases were observed on pears (1.00 log CFU/g), papayas (1.65 log CFU/g), and green bell peppers (1.72 log CFU/g). Pineapple samples did not support the growth of L. monocytogenes at 13°C with a significant reduction of 1.80 log CFU/g by day 6. L. monocytogenes levels significantly increased in fresh-cut lettuce at 13°C but remained stable on kale, cauliflower, and broccoli after 6 days of storage. Stable population was observed also on cantaloupe rinds up to 8 days at 24°C. While on the outer surface of bell peppers, the population level decreased below the detectable limit of the test (10 CFU/20 cm2) after 14 days of storage at 4°C. The results demonstrated variable survival behavior of L. monocytogenes on fresh-cut produce with produce type and storage temperature.
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Affiliation(s)
- Juan Moreira
- School of Nutrition and Food Sciences, Louisiana State University AgCenter, Baton Rouge, LA, United States
| | - Erika Mera
- School of Nutrition and Food Sciences, Louisiana State University AgCenter, Baton Rouge, LA, United States
| | - Vijay Singh Chhetri
- College of Agriculture and Food Sciences, Florida A&M University, Tallahassee, FL, United States
| | - Joan M. King
- School of Nutrition and Food Sciences, Louisiana State University AgCenter, Baton Rouge, LA, United States
| | - Thanos Gentimis
- Department of Experimental Statistics, Louisiana State University, Baton Rouge, LA, United States
| | - Achyut Adhikari
- School of Nutrition and Food Sciences, Louisiana State University AgCenter, Baton Rouge, LA, United States
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6
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Jaber N, Al-Remawi M. Evaluation of a novel water-soluble decanoic acid formulation as a fruit sanitizer. Int J Food Microbiol 2023; 388:110067. [PMID: 36608355 DOI: 10.1016/j.ijfoodmicro.2022.110067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 12/20/2022] [Accepted: 12/25/2022] [Indexed: 01/01/2023]
Abstract
Fruits irrigated with contaminated water can transmit various pathogens. High sugar content in fruits such as black cherry (BC) fruit encourages microbial proliferation. A novel water-soluble decanoic acid (WSDA) was evaluated as a fruit sanitizer and compared with other traditional fruit sanitizers such as ethanol, bleach, or dishwasher surfactants. WSDA sanitizer killed yeasts, molds and bacteria including E. coli microbes effectively as other sanitizers with (4 log cycle reduction) of microbial load. Furthermore, the bacterial sanitization mechanism i.e. bactericidal or bacteriostatic was evaluated for alcohol, bleaching and WASDA solutions. E. coli was selected as the model pathogen used for such comparison. Results indicated that the mechanism of action for the three sanitizer solutions against E. coli was bactericidal. The problem with most used fruit sanitizers is their negative influence on fruit quality in terms of physical, mechanical and taste properties. In addition, some led to toxicological and ecological concerns. Thus, studies were conducted to explore the changes in the exocarp cell structure of BC fruit upon exposure to WSDA and other sanitizers using microscopic investigation. WSDA could have a very mild or gentle effect on the BC fruit cells compared to other sanitizers. Alcohol, bleaching and dishwasher surfactant changed the cellular structures and the intercellular spaces. Sanitizers may also affect fruit swelling. WSDA showed an increase in percent weight gain but it was significantly (p < 0.05) much lower than dishwasher surfactant and bleaching solution. BC Fruit flesh firmness and hardness were investigated upon exposure to different sanitizer solutions. BC fruit treated with WSDA showed the highest firmness values. Some liquid sanitizers could affect fruit quality in terms of fruit taste. Sensory evaluation in terms of the sanitizer's smell, texture and hedonic of BC fruit after soaking in different sanitizers was carried out. All sensory parameters of BC fruit soaked with WSDA were similar with insignificant differences (p > 0.05) compared to BC fruit soaked in tap water. However, the sensory parameters were significantly different (p < 0.05) when compared with alcohol, bleach and dishwasher surfactant. This ensures that WSDA was superior to other evaluated sanitizers in terms of physical, mechanical and fruit quality.
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Affiliation(s)
- Nisrein Jaber
- Faculty of Pharmacy, Al Zaytoonah University of Jordan, Jordan
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7
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Tseng YH, Barbosa J, de Carvalho TB, Teixeira P. Microbiological Safety of Cut Melons Sold in Portuguese Retail Markets: A Pilot Study. Foods 2022; 11:foods11244010. [PMID: 36553753 PMCID: PMC9777610 DOI: 10.3390/foods11244010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 12/06/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
Due to the increasing consciousness of a healthy diet and pursuit of convenience among consumers, the market for fresh fruit is on the rise, and the melon is among the most welcome of fruits for its sensory attributes and nutritional properties. Consumption safety of cut fruit remains an issue of concern that may affect public health. This study aimed to perform the microbiological characterisation of a melon, Cucumis melo L. var. “Piel de Sapo”, cut by retailers, wrapped in plastic cling film and kept at room temperature in local fruit shops. In addition, the possible transfer of relevant foodborne pathogens, during slicing, from the peel to the interior of the melon, and bacterial growth, were also evaluated when the melon slices were stored at abusive temperatures for 2 days. In this pilot study, a low number of samples were characterised microbiologically (26 cut melons), and some isolates were identified by 16S rRNA sequencing. No Listeria spp. or Salmonella spp. were detected in any of the samples, while Escherichia coli and Staphylococcus aureus were present in four and six out of twenty-six samples, respectively. Following artificial contamination of melons with cocktails of Salmonella spp., E. coli and Listeria monocytogenes, it was observed that, despite the smaller number of L. monocytogenes recovered, all the pathogens were transferred from the contaminated peels to the interior of the melons. Furthermore, over storage time, significant differences were observed (p < 0.05) between the counts obtained from melon slices immediately after cutting (0 h), and after 24 and 48 h at 20 °C, with an increase of about 4 log CFU/g in all the pathogens. In conclusion, some cut melons classified as microbiologically unacceptable or unsatisfactory are being sold in local fruit shops in the Porto Metropolitan Area, Portugal. Although absent in the samples analysed, Salmonella spp. and L. monocytogenes, if present, can be transferred from the outside to the inside of the fruit by the cutting blade and, if not consumed immediately and stored at abusive temperatures, this ready-to-eat product poses a risk of infection. This pilot study, performed for the first time in Portugal under these conditions, clearly demonstrates the need for education campaigns to alert local sellers and consumers of the risk posed by cut melons.
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8
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Wang P, Pitts KB, Chavez DJ, Chen J. Microbial load on fresh peaches and hand gloves collected from selected packing facilities in Georgia. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2022.114244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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9
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Gerdes ME, Cruz-Cano R, Solaiman S, Ammons S, Allard SM, Sapkota AR, Micallef SA, Goldstein RER. Impact of irrigation water type and sampling frequency on Microbial Water Quality Profiles required for compliance with U.S. Food Safety Modernization Act Produce Safety Rule standards. ENVIRONMENTAL RESEARCH 2022; 205:112480. [PMID: 34863989 DOI: 10.1016/j.envres.2021.112480] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 11/26/2021] [Accepted: 11/29/2021] [Indexed: 06/13/2023]
Abstract
The U.S. Food Safety Modernization Act (FSMA) Produce Safety Rule (PSR) requires that farmers generate a Microbial Water Quality Profile (MWQP) from 20 samples per agricultural water source, taken over 2-4 years and five annual samples thereafter. Farmers must use the MWQP to ascertain a geometric mean (GM) of ≤126 CFU/100 mL and statistical threshold value (STV) of ≤410 CFU/100 mL of generic Escherichia coli. Farmers are responsible for collecting samples and paying for testing, incurring a financial and time burden. To determine if testing frequency can be reduced without compromising accuracy, water samples (n = 279) were collected from twelve sites in the U.S. Mid-Atlantic region from 2016 to 2018 comprising tidal brackish river, non-tidal fresh river, pond, vegetable processing, and reclaimed water. The GM and STV were calculated for all sites and water types using all samples, and for multiple sub-samples of <20 from each site and water type. A Monte Carlo simulation was used to determine the proportion of sub-sample sizes that yielded the same determination as the entire sample size of PSR standard compliance. Four sites, two pond and two reclaimed water sites, complied with PSR GM and STV requirements when using the entire sample set. When a water source's calculated GM and STV using the entire sample set hovered close to the PSR thresholds, sub-sample sizes approached the recommended 20 samples to reach a congruent compliance determination. However, 99% agreement was obtained with a sub-sample of five when the absolute difference between the GM and STV from total samples and the PSR thresholds was ≥2.6 and 4.5 log CFU/100 mL E. coli, respectively. These findings suggest that under certain conditions the MWQP may be generated with well below 20 samples, reducing the economic burden on farmers while still maintaining a representative MWQP.
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Affiliation(s)
- Megan E Gerdes
- Department of Epidemiology and Biostatistics, School of Public Health, University of Maryland, College Park, MD, USA
| | - Raul Cruz-Cano
- Department of Epidemiology and Biostatistics, School of Public Health, University of Maryland, College Park, MD, USA
| | - Sultana Solaiman
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, USA
| | - Samantha Ammons
- Department of Epidemiology and Biostatistics, School of Public Health, University of Maryland, College Park, MD, USA
| | - Sarah M Allard
- Maryland Institute for Applied and Environmental Health, School of Public Health, University of Maryland, College Park, MD, USA
| | - Amy R Sapkota
- Maryland Institute for Applied and Environmental Health, School of Public Health, University of Maryland, College Park, MD, USA
| | - Shirley A Micallef
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, USA; Center for Food Safety and Security Systems, University of Maryland, College Park, MD, USA
| | - Rachel E Rosenberg Goldstein
- Maryland Institute for Applied and Environmental Health, School of Public Health, University of Maryland, College Park, MD, USA.
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10
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Esteban-Cuesta I, Labrador M, Hunt K, Reese S, Fischer J, Schwaiger K, Gareis M. Phenotypic and Genetic Comparison of a Plant-Internalized and an Animal-Isolated Salmonella Choleraesuis Strain. Microorganisms 2021; 9:microorganisms9081554. [PMID: 34442630 PMCID: PMC8398053 DOI: 10.3390/microorganisms9081554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/05/2021] [Accepted: 07/16/2021] [Indexed: 11/16/2022] Open
Abstract
Contamination of fresh produce with human pathogens poses an important risk for consumers, especially after raw consumption. Moreover, if microorganisms are internalized, no removal by means of further hygienic measures would be possible. Human pathogenic bacteria identified in these food items are mostly of human or animal origin and an adaptation to this new niche and particularly for internalization would be presumed. This study compares a plant-internalized and an animal-borne Salmonella enterica subsp. enterica serovar Choleraesuis aiming at the identification of adaptation of the plant-internalized strain to its original environment. For this purpose, a phenotypical characterization by means of growth curves under conditions resembling the indigenous environment from the plant-internalized strain and further analyses using Pulsed-field gel electrophoresis and Matrix-assisted laser desorption ionization time of flight spectrometry were assessed. Furthermore, comparative genomic analyses by means of single nucleotide polymorphisms and identification of present/absent genes were performed. Although some phenotypical and genetic differences could be found, no signs of a specific adaptation for colonization and internalization in plants could be clearly identified. This could suggest that any Salmonella strain could directly settle in this niche without any evolutionary process being necessary. Further comparative analysis including internalized strains would be necessary to assess this question. However, these kinds of strains are not easily available.
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Affiliation(s)
- Irene Esteban-Cuesta
- Chair of Food Safety, Veterinary Faculty, LMU Munich, 85764 Oberschleissheim, Germany; (K.H.); (K.S.); (M.G.)
- Correspondence:
| | - Mirian Labrador
- Departamento de Producción Animal y Ciencia de los Alimentos, Veterinary Faculty, Instituto Agroalimentario de Aragon-IA2, University of Zaragoza-CITA, 50013 Zaragoza, Spain;
| | - Katharina Hunt
- Chair of Food Safety, Veterinary Faculty, LMU Munich, 85764 Oberschleissheim, Germany; (K.H.); (K.S.); (M.G.)
| | - Sven Reese
- Chair of Anatomy, Histology and Embryology, Department of Veterinary Sciences, Faculty of Veterinary Medicine, LMU Munich, 80539 Munich, Germany;
| | - Jennie Fischer
- National Salmonella Reference Laboratory, Unit Food Microbiology, Host-Pathogen-Interactions, Department of Biological Safety, German Federal Institute for Risk Assessment (Bundesinstitut für Risikobewertung—BfR), 12277 Berlin, Germany;
| | - Karin Schwaiger
- Chair of Food Safety, Veterinary Faculty, LMU Munich, 85764 Oberschleissheim, Germany; (K.H.); (K.S.); (M.G.)
- Unit of Food Hygiene and Technology, Institute of Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, 1220 Vienna, Austria
| | - Manfred Gareis
- Chair of Food Safety, Veterinary Faculty, LMU Munich, 85764 Oberschleissheim, Germany; (K.H.); (K.S.); (M.G.)
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11
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Stahr MN, Quesada-Ocampo LM. Effects of Water Temperature, Inoculum Concentration and Age, and Sanitizers on Infection of Ceratocystis fimbriata, Causal Agent of Black Rot in Sweetpotato. PLANT DISEASE 2021; 105:1365-1372. [PMID: 33079026 DOI: 10.1094/pdis-07-20-1475-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Black rot, caused by Ceratocystis fimbriata, is a devastating postharvest disease of sweetpotato that recently re-emerged in 2014. Although the disease is known to develop in storage and during export to overseas markets, little is known as to how pathogen dispersal occurs. This study was designed to investigate dump tank water as a means of dispersal through four different types of water treatments: inoculum concentration (0, 5, 5 × 101, 5 × 102, and 5 × 103 spores/ml), inoculum age (0, 24, 48, 96, and 144 h), water temperature (10°C, 23°C, 35°C, and 45°C), and presence of a water sanitizer (DryTec, SaniDate, FruitGard, and Selectrocide). Wounded and nonwounded sweetpotato storage roots were soaked in each water treatment for 20 min, stored at 29°C for a 14-day period, and rated for disease incidence every other day. Disease was observed in sweetpotato storage roots in all water treatments tested, except in the negative controls. Disease incidence decreased with both inoculum concentration and inoculum age, yet values of 16.26% and up to 50% were observed for roots exposed to 5 spores/ml and 144-h water treatments, respectively. Sanitizer products that contained a form of chlorine as the active ingredient significantly reduced disease incidence in storage roots when compared with control roots and roots exposed to a hydrogen-peroxide based product. Finally, no significant differences in final incidence were detected in wounded sweetpotato storage roots exposed to water treatments of any temperature, but a significant reduction in disease progression was observed in the 45°C treatment. These findings indicate that if packing line dump tanks are improperly managed, they can aid C. fimbriata dispersal through the build-up of inoculum as infected roots are unknowingly washed after storage. Chlorine-based sanitizers can reduce infection when applied after root washing and not in the presence of high organic matter typically found in dump tanks.
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Affiliation(s)
- Madison N Stahr
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695-7613
| | - Lina M Quesada-Ocampo
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695-7613
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12
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Frankish EJ, Bozkurt H, Ross T, Phan-Thien KY, Luning PA, Bell TL, McConchie R. An observational assessment of Australian apple production practices for microbial control. Food Control 2021. [DOI: 10.1016/j.foodcont.2020.107767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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13
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He Y, Chen R, Qi Y, Salazar JK, Zhang S, Tortorello ML, Deng X, Zhang W. Survival and transcriptomic response of Salmonella enterica on fresh-cut fruits. Int J Food Microbiol 2021; 348:109201. [PMID: 33930836 DOI: 10.1016/j.ijfoodmicro.2021.109201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 03/26/2021] [Accepted: 04/13/2021] [Indexed: 01/21/2023]
Abstract
Salmonella enterica is frequently implicated in foodborne disease outbreaks associated with fresh-cut fruits. In the U.S., more than one third of fruit-related outbreaks have been linked to two S. enterica serotypes Newport and Typhimurium. Approximately 80% of fruit-related human salmonellosis cases were associated with tomatoes, cantaloupes and cucumbers. In this study, we investigated the population dynamics of S. Newport and S. Typhimurium on fresh-cut tomato, cantaloupe, cucumber and apple under short-term storage conditions. We further compared the transcriptomic profiles of a S. Newport strain on fresh-cut tomato and cantaloupe using high-throughput RNA-seq. We demonstrated that both S. enterica Newport and Typhimurium survived well on various fresh-cut fruit items under refrigeration storage conditions, independent of inoculation levels. However, S. enterica displayed variable survival behaviors on different types of fruits. For example, at 7 d storage, the population of S. enterica reduced less than 0.2 log (p > 0.05) on fresh-cut tomato and cantaloupe, in contrast to ~0.5 log (p < 0.05) on cucumber and apple. RNA-seq analysis suggested that S. enterica mediates its survival on fresh-cut fruits through differentially regulating genes involved in specific carbon utilization and metabolic pathways. Several known bacterial virulence factors (e.g., pag gene) were found to be differentially regulated on fresh-cut tomato and cantaloupe, suggesting a link between the events of food contamination and subsequent human infection. Findings from this study contribute to a better understanding of S. enterica survival mechanisms on fresh-cut produce.
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Affiliation(s)
- Yingshu He
- Department of Food Science and Nutrition & Institute for Food Safety and Health, Illinois Institute of Technology, Bedford Park, IL, USA; Center for Food Safety, College of Agricultural and Environmental Sciences, University of Georgia, Griffin, GA, USA.
| | - Ruixi Chen
- Department of Food Science and Nutrition & Institute for Food Safety and Health, Illinois Institute of Technology, Bedford Park, IL, USA
| | - Yan Qi
- Center for Food Safety, College of Agricultural and Environmental Sciences, University of Georgia, Griffin, GA, USA
| | - Joelle K Salazar
- Division of Food Processing Science and Technology, U. S. Food and Drug Administration, Bedford Park, IL, USA
| | - Shimei Zhang
- Department of Food Science and Nutrition & Institute for Food Safety and Health, Illinois Institute of Technology, Bedford Park, IL, USA
| | - Mary Lou Tortorello
- Division of Food Processing Science and Technology, U. S. Food and Drug Administration, Bedford Park, IL, USA
| | - Xiangyu Deng
- Center for Food Safety, College of Agricultural and Environmental Sciences, University of Georgia, Griffin, GA, USA
| | - Wei Zhang
- Department of Food Science and Nutrition & Institute for Food Safety and Health, Illinois Institute of Technology, Bedford Park, IL, USA
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14
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Harrand AS, Guariglia-Oropeza V, Skeens J, Kent D, Wiedmann M. Nature versus Nurture: Assessing the Impact of Strain Diversity and Pregrowth Conditions on Salmonella enterica, Escherichia coli, and Listeria Species Growth and Survival on Selected Produce Items. Appl Environ Microbiol 2021; 87:e01925-20. [PMID: 33397695 PMCID: PMC8105001 DOI: 10.1128/aem.01925-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 12/21/2020] [Indexed: 11/20/2022] Open
Abstract
Inoculation studies are important when assessing microbial survival and growth in food products. These studies typically involve the pregrowth of multiple strains of a target pathogen under a single condition; this emphasizes strain diversity. To gain a better understanding of the impacts of strain diversity ("nature") and pregrowth conditions ("nurture") on subsequent bacterial growth in foods, we assessed the growth and survival of Salmonella enterica (n = 5), Escherichia coli (n = 6), and Listeria (n = 5) inoculated onto tomatoes, precut lettuce, and cantaloupe rind, respectively. Pregrowth conditions included (i) 37°C to stationary phase (baseline), (ii) low pH, (iii) high salt, (iv) reduced water activity, (v) log phase, (vi) minimal medium, and (vii) 21°C. Inoculated tomatoes were incubated at 21°C; lettuce and cantaloupe were incubated at 7°C. Bacterial counts were assessed over three phases, including initial reduction (phase 1), change in bacterial numbers over the first 24 h of incubation (phase 2), and change over the 7-day incubation (phase 3). E. coli showed overall decline in counts (<1 log) over the 7-day period, except for a <1-log increase after pregrowth in high salt and to mid-log phase. In contrast, S. enterica and Listeria showed regrowth after an initial reduction. Pregrowth conditions had a substantial and significant effect on all three phases of S. enterica and E. coli population dynamics on inoculated produce, whereas strain did not show a significant effect. For Listeria, both pregrowth conditions and strain affected changes in phase 2 but not phases 1 and 3.IMPORTANCE Our findings suggest that inclusion of multiple pregrowth conditions in inoculation studies can best capture the range of growth and survival patterns expected for Salmonella enterica and Escherichia coli present on produce. This is particularly important for fresh and fresh-cut produce, where stress conditions encountered by pathogens prior to contamination can vary widely, making selection of a typical pregrowth condition virtually impossible. Pathogen growth and survival data generated using multiple pregrowth conditions will allow for more robust microbial risk assessments that account more accurately for uncertainty.
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Affiliation(s)
| | | | - Jordan Skeens
- Department of Food Science, Cornell University, Ithaca, New York, USA
| | - David Kent
- Department of Statistical Science, Cornell University, Ithaca, New York, USA
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, New York, USA
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15
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Díaz-Torres O, Lugo-Melchor OY, de Anda J, Gradilla-Hernández MS, Amézquita-López BA, Meza-Rodríguez D. Prevalence, Distribution, and Diversity of Salmonella Strains Isolated From a Subtropical Lake. Front Microbiol 2020; 11:521146. [PMID: 33042046 PMCID: PMC7518123 DOI: 10.3389/fmicb.2020.521146] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 08/17/2020] [Indexed: 01/23/2023] Open
Abstract
This study investigated the prevalence, serovar distribution, antimicrobial resistance, and pulsed field gel electrophoresis (PFGE) typing of Salmonella enterica isolated from Lake Zapotlán, Jalisco, Mexico. Additionally, the association of the presence of Salmonella with physicochemical and environmental parameters was analyzed using Pearson correlation analysis and principal component analysis (PCA). Salmonella spp. were identified in 19 of 63 (30.15%) samples. The prevalence of Salmonella was positively correlated with air temperature, electrical conductivity, pH, and dissolved oxygen and negatively correlated with relative humidity, water temperature, turbidity, and precipitation. The predominant serotype identified was Agona (68.48%), followed by Weltevreden (5.26%), Typhimurium (5.26%), and serogroup B (21.05%). Overall, the highest detected antimicrobial resistance was toward colistin (73.68%), followed by sulfamethoxazole (63.15%), tetracycline (57.89%), nalidixic acid (52.63%), and trimethoprim (52.63%). All Salmonella strains were genetically diverse, with a total of 11 XbaI and four BlnI profiles on PFGE. The use of these two enzymes allowed differentiate strains of Salmonella of the same serotype. The results obtained in this study contribute to a better understanding of the Salmonella spp. ecology in an endorheic subtropical lake and provide information for decision makers to propose and implement effective strategies to control point and non-point sources of pathogen contamination.
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Affiliation(s)
- Osiris Díaz-Torres
- Unidad de Servicios Analíticos y Metrológicos, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, Guadalajara, Mexico
| | - Ofelia Yadira Lugo-Melchor
- Unidad de Servicios Analíticos y Metrológicos, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, Guadalajara, Mexico
| | - José de Anda
- Departamento de Tecnología Ambiental, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, Guadalajara, Mexico
| | | | - Bianca A Amézquita-López
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Sinaloa, Culiacán Rosales, Mexico
| | - Demetrio Meza-Rodríguez
- Departamento de Ecología y Recursos Naturales, Universidad de Guadalajara, Autlán de Navarro, Mexico
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16
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Both Handwashing and an Alcohol-Based Hand Sanitizer Intervention Reduce Soil and Microbial Contamination on Farmworker Hands during Harvest, but Produce Type Matters. Appl Environ Microbiol 2020; 86:AEM.00780-20. [PMID: 32680869 DOI: 10.1128/aem.00780-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/08/2020] [Indexed: 01/04/2023] Open
Abstract
Hand hygiene interventions are critical for reducing farmworker hand contamination and preventing the spread of produce-associated illness. Hand hygiene effectiveness may be produce-commodity specific, which could influence implementation strategies. This study's goal was to determine if produce commodity influences the ability of handwashing with soap and water or two-step alcohol-based hand sanitizer (ABHS) interventions to reduce soil and bacteria on farmworker hands. Farmworkers (n = 326) harvested produce (cantaloupe, jalapeño, and tomato) for 30 to 90 minutes before engaging in handwashing, two-step ABHS (jalapeño and cantaloupe), or no hand hygiene. Hands were rinsed to measure amounts of soil (absorbance at 600 nm) and indicator bacteria (coliforms, Enterococcus sp., generic Escherichia coli, and Bacteroidales universal [AllBac] and human-specific [BFD] 16S rRNA gene markers). Without hand hygiene, bacterial concentrations (0.88 to 5.1 log10 CFU/hand) on hands significantly differed by the produce commodity harvested. Moderate significant correlations (ρ = -0.41 to 0.56) between soil load and bacterial concentrations were observed. There were significant produce-commodity-specific differences in the ability of handwashing and two-step ABHS interventions to reduce soil (P < 0.0001), coliforms (P = 0.002), and Enterococcus sp. (P = 0.003), but not the Bacteroidales markers AllBac (P = 0.4) or BFD (P = 0.3). Contamination on hands of farmworkers who harvested cantaloupe was more difficult to remove. Overall, we found that a two-step ABHS intervention was similar to handwashing with soap and water at reducing bacteria on farmworker hands. In summary, produce commodity type should be considered when developing hand hygiene interventions on farms.IMPORTANCE This study demonstrated that the type of produce commodity handled influences the ability of handwashing with soap and water or a two-step alcohol-based hand sanitizer (ABHS) intervention to reduce soil and bacterial hand contamination. Handwashing with soap and water, as recommended by the FDA's Produce Safety Rule, when tested in three agricultural environments, does not always reduce bacterial loads. Consistent with past results, we found that the two-step ABHS method performed similarly to handwashing with soap and water but also does not always reduce bacterial loads in these contexts. Given the ease of use of the two-step ABHS method, which may increase compliance, the two-step ABHS method should be further evaluated and possibly considered for implementation in the agricultural environment. Taken together, these results provide important information on hand hygiene effectiveness in three agricultural contexts.
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17
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Burris KP, Simmons OD, Webb HM, Moore RG, Jaykus LA, Zheng J, Reed E, Ferreira CM, Brown E, Bell RL. Salmonella enterica colonization and fitness in pre-harvest cantaloupe production. Food Microbiol 2020; 93:103612. [PMID: 32912584 DOI: 10.1016/j.fm.2020.103612] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/14/2020] [Accepted: 07/29/2020] [Indexed: 11/25/2022]
Abstract
Cantaloupes have emerged as significant vehicles of widespread foodborne illness outbreaks caused by bacterial pathogens, including Salmonella. The purpose of this study was to investigate the efficiency of Salmonella colonization and internalization in cantaloupes by relevant routes of contamination. Cantaloupe plants (Cucumis melo 'reticulatus') from two cultivars 'Athena' (Eastern) and 'Primo' (Western) were grown from commercial seed. Plants were maintained in the NCSU BSL-3P phytotron greenhouse. Salmonella enterica (a cocktail of cantaloupe-associated outbreak serovars Javiana, Newport, Panama, Poona and Typhimurium) contamination was introduced via blossoms or soil at ca. 4.4 log10 CFU/blossom or 8.4 log10 CFU/root zone, respectively. Cantaloupes were analyzed for Salmonella by enrichment in accordance with modified FDA-BAM methods. Five randomly chosen colonies from each Salmonella-positive sample were typed using the Agilent 2100 bioanalyzer following multiplex PCR. Data were analyzed for prevalence of contamination and serovar predominance in fruit, stems and soil. Of the total cantaloupe fruit harvested from Salmonella-inoculated blossoms (n = 63), 89% (56/63) were externally contaminated and 73% (46/63) had Salmonella internalized into the fruit. Serovar Panama was the most commonly isolated from the surface of fruit while S. Panama and S. Poona were the most prevalent inside the fruit. When soil was inoculated with Salmonella at one day post-transplant, 13% (8/60) of the plants were shown to translocate the organism to the lower stem (ca. 4 cm) by 7 days post-inoculation (dpi). We observed Salmonella persistence in the soil up to 60 dpi with S. Newport being the predominant serovar at 10 and 20 dpi. These data demonstrate that contaminated soil and blossoms can lead to Salmonella internalization into the plant or fruit at a relatively high frequency.
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Affiliation(s)
- Kellie P Burris
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC, USA; Center for Food Safety & Applied Nutrition, U.S. Food & Drug Administration, College Park, MD, USA.
| | - Otto D Simmons
- Department of Horticultural Science, North Carolina State University, Raleigh, NC, USA
| | - Hannah M Webb
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC, USA
| | - Robin Grant Moore
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC, USA
| | - Lee-Ann Jaykus
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC, USA
| | - Jie Zheng
- Center for Food Safety & Applied Nutrition, U.S. Food & Drug Administration, College Park, MD, USA
| | - Elizabeth Reed
- Center for Food Safety & Applied Nutrition, U.S. Food & Drug Administration, College Park, MD, USA
| | - Christina M Ferreira
- Center for Food Safety & Applied Nutrition, U.S. Food & Drug Administration, College Park, MD, USA
| | - Eric Brown
- Center for Food Safety & Applied Nutrition, U.S. Food & Drug Administration, College Park, MD, USA
| | - Rebecca L Bell
- Center for Food Safety & Applied Nutrition, U.S. Food & Drug Administration, College Park, MD, USA
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18
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Dankwa AS, Machado RM, Perry JJ. Sources of food contamination in a closed hydroponic system. Lett Appl Microbiol 2020; 70:55-62. [PMID: 31660628 DOI: 10.1111/lam.13243] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/23/2019] [Accepted: 10/23/2019] [Indexed: 11/30/2022]
Abstract
This study investigated potential contamination sources in a commercial, closed hydroponic system. Water, substrate and lettuce (Lactuca sativa) samples were evaluated for microbiological indicator populations, including aerobic plate count (APC), coliform bacteria (CB) and yeast and mould (YM). Listeria spp. detection via cultural enrichment and agglutination was negative for all samples. Peat moss substrate (postharvest) had the highest counts for APC (6·8 log CFU per g), CB (4·5 log MPN per g) and YM (5·1 and 4·8 log CFU per g respectively). Roots embedded in plugs demonstrated counts for all populations nearly as high as the substrate. Among water samples, a seedling water reservoir housing germinated plants yielded the highest count for APC (5·1 log CFU per g) and CB (2·4 log MPN per g) likely due to the large numbers of plugs and their close proximity in the reservoir. Harvested lettuce leaves demonstrated higher APC (4·1 log CFU per g) than preharvest leaves (1·7 log CFU per g) due to the transfer of microbes from the root ball. These data suggest that substrates are a significant potential source of contamination in hydroponic systems and likely facilitate microbial transfer to harvested leaves. There is, therefore, the need to further investigate mitigation of potential contamination events. SIGNIFICANCE AND IMPACT OF THE STUDY: Hydroponic production is known to provide safe, clean produce. This study, however, suggests that the hydroponic substrate (peat moss plug) is a possible source of contamination in the hydroponic system. This finding is important as most harvested hydroponic lettuces are packaged and sold with substrate and root ball intact. This implies a high probability of microbial transfer from the root ball to edible harvested lettuce leaves.
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Affiliation(s)
- A S Dankwa
- School of Food and Agriculture, University of Maine, Orono, ME, USA
| | - R M Machado
- School of Food and Agriculture, University of Maine, Orono, ME, USA
- Cooperative Extension, University of Maine, Orono, ME, USA
| | - J J Perry
- School of Food and Agriculture, University of Maine, Orono, ME, USA
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19
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The Role of Pathogenic E. coli in Fresh Vegetables: Behavior, Contamination Factors, and Preventive Measures. Int J Microbiol 2019; 2019:2894328. [PMID: 31885595 PMCID: PMC6899298 DOI: 10.1155/2019/2894328] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 11/11/2019] [Indexed: 12/31/2022] Open
Abstract
Many raw vegetables, such as tomato, chili, onion, lettuce, arugula, spinach, and cilantro, are incorporated into fresh dishes including ready-to-eat salads and sauces. The consumption of these foods confers a high nutritional value to the human diet. However, the number of foodborne outbreaks associated with fresh produce has been increasing, with Escherichia coli being the most common pathogen associated with them. In humans, pathogenic E. coli strains cause diarrhea, hemorrhagic colitis, hemolytic uremic syndrome, and other indications. Vegetables can be contaminated with E. coli at any point from pre- to postharvest. This bacterium is able to survive in many environmental conditions due to a variety of mechanisms, such as adhesion to surfaces and internalization in fresh products, thereby limiting the usefulness of conventional processing and chemical sanitizing methods used by the food industry. The aim of this review is to provide a general description of the behavior and importance of pathogenic E. coli in ready-to-eat vegetable dishes. This information can contribute to the development of effective control measures for enhancing food safety.
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20
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Kim C, Pao S. Utilizing kitchen steamers to inactivate
Listeria monocytogenes
and
Salmonella enterica
on whole cantaloupe melons. J Food Saf 2019. [DOI: 10.1111/jfs.12653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chyer Kim
- Agricultural Research StationVirginia State University Petersburg Virginia
| | - Steven Pao
- Department of Food Science and NutritionCalifornia State University Fresno California
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21
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Growth and survival of Salmonella enterica and Listeria monocytogenes on fresh-cut produce and their juice extracts: Impacts and interactions of food matrices and temperature abuse conditions. Food Control 2019. [DOI: 10.1016/j.foodcont.2018.12.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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22
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Alegbeleye OO, Singleton I, Sant'Ana AS. Sources and contamination routes of microbial pathogens to fresh produce during field cultivation: A review. Food Microbiol 2018; 73:177-208. [PMID: 29526204 PMCID: PMC7127387 DOI: 10.1016/j.fm.2018.01.003] [Citation(s) in RCA: 238] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/31/2017] [Accepted: 01/02/2018] [Indexed: 12/17/2022]
Abstract
Foodborne illness resulting from the consumption of contaminated fresh produce is a common phenomenon and has severe effects on human health together with severe economic and social impacts. The implications of foodborne diseases associated with fresh produce have urged research into the numerous ways and mechanisms through which pathogens may gain access to produce, thereby compromising microbiological safety. This review provides a background on the various sources and pathways through which pathogenic bacteria contaminate fresh produce; the survival and proliferation of pathogens on fresh produce while growing and potential methods to reduce microbial contamination before harvest. Some of the established bacterial contamination sources include contaminated manure, irrigation water, soil, livestock/ wildlife, and numerous factors influence the incidence, fate, transport, survival and proliferation of pathogens in the wide variety of sources where they are found. Once pathogenic bacteria have been introduced into the growing environment, they can colonize and persist on fresh produce using a variety of mechanisms. Overall, microbiological hazards are significant; therefore, ways to reduce sources of contamination and a deeper understanding of pathogen survival and growth on fresh produce in the field are required to reduce risk to human health and the associated economic consequences.
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Affiliation(s)
| | - Ian Singleton
- School of Applied Sciences, Sighthill Campus, Edinburgh Napier University, Edinburgh, UK
| | - Anderson S Sant'Ana
- Department of Food Science, Faculty of Food Engineering, University of Campinas, Campinas, São Paulo, Brazil.
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23
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Chhetri VS, Fontenot K, Strahan R, Yemmireddy VK, Parraga Estrada KJ, Adhikari A. Effect of surrounding vegetation on microbial survival or die‐off on watermelon surface in an agriculture setting. J Food Saf 2018. [DOI: 10.1111/jfs.12520] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Vijay Singh Chhetri
- School of Nutrition and Food Sciences, Louisiana State University Agricultural Center Baton Rouge Louisiana
| | - Kathryn Fontenot
- School of Plant, Environmental, and Soil Sciences, Louisiana State University Agricultural Center Baton Rouge Louisiana
| | - Ronald Strahan
- School of Plant, Environmental, and Soil Sciences, Louisiana State University Agricultural Center Baton Rouge Louisiana
| | - Veerachandra K. Yemmireddy
- School of Nutrition and Food Sciences, Louisiana State University Agricultural Center Baton Rouge Louisiana
| | | | - Achyut Adhikari
- School of Nutrition and Food Sciences, Louisiana State University Agricultural Center Baton Rouge Louisiana
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24
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Weller DL, Kovac J, Kent DJ, Roof S, Tokman JI, Mudrak E, Kowalcyk B, Oryang D, Aceituno A, Wiedmann M. Escherichia coli transfer from simulated wildlife feces to lettuce during foliar irrigation: A field study in the Northeastern United States. Food Microbiol 2017; 68:24-33. [PMID: 28800822 DOI: 10.1016/j.fm.2017.06.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 06/12/2017] [Accepted: 06/12/2017] [Indexed: 11/20/2022]
Abstract
Wildlife intrusion has been associated with pathogen contamination of produce. However, few studies have examined pathogen transfer from wildlife feces to pre-harvest produce. This study was performed to calculate transfer coefficients for Escherichia coli from simulated wildlife feces to field-grown lettuce during irrigation. Rabbit feces inoculated with a 3-strain cocktail of non-pathogenic E. coli were placed in a lettuce field 2.5-72 h before irrigation. Following irrigation, the E. coli concentration on the lettuce was determined. After exclusion of an outlier with high E. coli levels (Most Probable Number = 5.94*108), the average percent of E. coli in the feces that transferred to intact lettuce heads was 0.0267% (Standard Error [SE] = 0.0172). Log-linear regression showed that significantly more E. coli transferred to outer leaves compared to inner leaves (Effect = 1.3; 95% Confidence Interval = 0.4, 2.1). Additionally, the percent of E. coli that transferred from the feces to the lettuce decreased significantly with time after fecal placement, and as the distance between the lettuce and the feces, and the lettuce and the sprinklers increased. These findings provide key data that may be used in future quantitative risk assessments to identify potential intervention strategies for reducing food safety risks associated with fresh produce.
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Affiliation(s)
- Daniel L Weller
- Department of Food Science, Stocking Hall, Cornell University, Ithaca, NY 14853, USA
| | - Jasna Kovac
- Department of Food Science, Stocking Hall, Cornell University, Ithaca, NY 14853, USA
| | - David J Kent
- Department of Food Science, Stocking Hall, Cornell University, Ithaca, NY 14853, USA
| | - Sherry Roof
- Department of Food Science, Stocking Hall, Cornell University, Ithaca, NY 14853, USA
| | - Jeffrey I Tokman
- Department of Food Science, Stocking Hall, Cornell University, Ithaca, NY 14853, USA
| | - Erika Mudrak
- Cornell Statistical Consulting Unit, Savage Hall, Cornell University, Ithaca, NY 14853, USA
| | | | - David Oryang
- U.S. Food and Drug Administration, 5001 Campus Drive, College Park, MD 20740, USA
| | - Anna Aceituno
- RTI International, 3040 E Cornwallis Rd, Durham, NC 27709, USA
| | - Martin Wiedmann
- Department of Food Science, Stocking Hall, Cornell University, Ithaca, NY 14853, USA.
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Macarisin D, Wooten A, De Jesus A, Hur M, Bae S, Patel J, Evans P, Brown E, Hammack T, Chen Y. Internalization of Listeria monocytogenes in cantaloupes during dump tank washing and hydrocooling. Int J Food Microbiol 2017; 257:165-175. [DOI: 10.1016/j.ijfoodmicro.2017.06.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 05/20/2017] [Accepted: 06/18/2017] [Indexed: 11/30/2022]
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Weller DL, Kovac J, Roof S, Kent DJ, Tokman JI, Kowalcyk B, Oryang D, Ivanek R, Aceituno A, Sroka C, Wiedmann M. Survival of Escherichia coli on Lettuce under Field Conditions Encountered in the Northeastern United States. J Food Prot 2017; 80:1214-1221. [PMID: 28632416 DOI: 10.4315/0362-028x.jfp-16-419] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Although wildlife intrusion and untreated manure have been associated with microbial contamination of produce, relatively few studies have examined the survival of Escherichia coli on produce under field conditions following contamination (e.g., via splash from wildlife feces). This experimental study was performed to estimate the die-off rate of E. coli on preharvest lettuce following contamination with a fecal slurry. During August 2015, field-grown lettuce was inoculated via pipette with a fecal slurry that was spiked with a three-strain cocktail of rifampin-resistant nonpathogenic E. coli. Ten lettuce heads were harvested at each of 13 time points following inoculation (0, 2.5, 5, and 24 h after inoculation and every 24 h thereafter until day 10). The most probable number (MPN) of E. coli on each lettuce head was determined, and die-off rates were estimated. The relationship between sample time and the log MPN of E. coli per head was modeled using a segmented linear model. This model had a breakpoint at 106 h (95% confidence interval = 69, 142 h) after inoculation, with a daily decrease of 0.70 and 0.19 log MPN for 0 to 106 h and 106 to 240 h following inoculation, respectively. These findings are consistent with die-off rates obtained in similar studies that assessed E. coli survival on produce following irrigation. Overall, these findings provide die-off rates for E. coli on lettuce that can be used in future quantitative risk assessments.
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Affiliation(s)
- Daniel L Weller
- 1 Department of Food Science, Cornell University, Ithaca, New York 14853
| | - Jasna Kovac
- 1 Department of Food Science, Cornell University, Ithaca, New York 14853
| | - Sherry Roof
- 1 Department of Food Science, Cornell University, Ithaca, New York 14853
| | - David J Kent
- 1 Department of Food Science, Cornell University, Ithaca, New York 14853
| | - Jeffrey I Tokman
- 1 Department of Food Science, Cornell University, Ithaca, New York 14853
| | - Barbara Kowalcyk
- 2 RTI International, Research Triangle Park, North Carolina 27709
| | - David Oryang
- 3 U.S. Food and Drug Administration, College Park, Maryland 20740
| | - Renata Ivanek
- 4 Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York 14853
| | - Anna Aceituno
- 2 RTI International, Research Triangle Park, North Carolina 27709
| | - Christopher Sroka
- 5 Department of Economics, Applied Statistics, and International Business, New Mexico State University, Las Cruces, New Mexico 88003, USA
| | - Martin Wiedmann
- 1 Department of Food Science, Cornell University, Ithaca, New York 14853
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Ximenes E, Hoagland L, Ku S, Li X, Ladisch M. Human pathogens in plant biofilms: Formation, physiology, and detection. Biotechnol Bioeng 2017; 114:1403-1418. [PMID: 28067424 DOI: 10.1002/bit.26247] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/05/2017] [Accepted: 01/05/2017] [Indexed: 12/29/2022]
Affiliation(s)
- Eduardo Ximenes
- Laboratory of Renewable Resources Engineering; Purdue University; West Lafayette Indiana 47907-2022
- Department of Agricultural and Biological Engineering; Purdue University; West Lafayette Indiana
| | - Lori Hoagland
- Horticulture and Landscape Architecture; Purdue University; West Lafayette Indiana
| | - Seockmo Ku
- Laboratory of Renewable Resources Engineering; Purdue University; West Lafayette Indiana 47907-2022
- Department of Agricultural and Biological Engineering; Purdue University; West Lafayette Indiana
| | - Xuan Li
- Laboratory of Renewable Resources Engineering; Purdue University; West Lafayette Indiana 47907-2022
| | - Michael Ladisch
- Laboratory of Renewable Resources Engineering; Purdue University; West Lafayette Indiana 47907-2022
- Department of Agricultural and Biological Engineering; Purdue University; West Lafayette Indiana
- Weldon School of Biomedical Engineering; Purdue University; West Lafayette Indiana
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Survival and growth of Listeria monocytogenes on whole cantaloupes is dependent on site of contamination and storage temperature. Int J Food Microbiol 2016; 234:65-70. [DOI: 10.1016/j.ijfoodmicro.2016.06.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/31/2016] [Accepted: 06/22/2016] [Indexed: 11/18/2022]
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Heredia N, Caballero C, Cárdenas C, Molina K, García R, Solís L, Burrowes V, Bartz FE, de Aceituno AF, Jaykus LA, García S, Leon J. Microbial Indicator Profiling of Fresh Produce and Environmental Samples from Farms and Packing Facilities in Northern Mexico. J Food Prot 2016; 79:1197-209. [PMID: 27357040 DOI: 10.4315/0362-028x.jfp-15-499] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To compare microbiological indicator and pathogen contamination among different types of fresh produce and environmental samples along the production chain, 636 samples of produce (rinsates from cantaloupe melons, jalapeño peppers, and tomatoes) and environmental samples (rinsates from hands of workers, soil, and water) were collected at four successive steps in the production process (from the field before harvest through the packing facility) on 11 farms in northern Mexico during 2011 and 2012. Samples were assayed for enteric pathogens (Escherichia coli O157:H7, other Shiga toxigenic E. coli, Salmonella, and Listeria monocytogenes) and microbial indicators (coliforms, other E. coli strains, and Enterococcus spp.). Salmonella was the only pathogen detected; it was found in one preharvest jalapeño sample (detection limits: 0.0033 CFU/ml in produce and hand samples, 0.0013 CFU/ml in water, and 0.04 CFU/g in soil). Microbial indicator profiles for produce, worker hands, and soil from jalapeño and tomato farms were similar, but cantaloupe farm samples had higher indicator levels (P < 0.05 for all comparisons) on fruit (6.5, 2.8, and 7.2 log CFU per fruit) and hands (6.6, 3.1, and 7.1 log CFU per hand) for coliforms, E. coli, and Enterococcus, respectively, and lower E. coli levels in soil (<1 CFU/g). In water from tomato farms, E. coli indicators were significantly more prevalent (70 to 89% of samples were positive; P = 0.01 to 0.02), and geometric mean levels were higher (0.3 to 0.6 log CFU/100 ml) than those in cantaloupe farm water (32 to 38% of samples were positive, geometric mean <1 CFU/100 ml). Microbial indicators were present during all production steps, but prevalence and levels were generally highest at the final on-farm production step (the packing facility) (P < 0.03 for significant comparisons). The finding that microbial contamination on produce farms is influenced by produce type and production step can inform the design of effective approaches to mitigate microbial contamination.
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Affiliation(s)
- Norma Heredia
- Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo Léon, Apostado Postal 124-F, San Nicolás, Nuevo Léon 66451, México
| | - Cindy Caballero
- Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo Léon, Apostado Postal 124-F, San Nicolás, Nuevo Léon 66451, México
| | - Carmen Cárdenas
- Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apostado Postal 124-F, San Nicolás, Nuevo León 66451, México
| | - Karina Molina
- Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apostado Postal 124-F, San Nicolás, Nuevo León 66451, México
| | - Rafael García
- Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apostado Postal 124-F, San Nicolás, Nuevo León 66451, México
| | - Luisa Solís
- Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apostado Postal 124-F, San Nicolás, Nuevo León 66451, México
| | - Vanessa Burrowes
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, 1518 Clifton Road N.E., Atlanta, Georgia 30322, USA
| | - Faith E Bartz
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, 1518 Clifton Road N.E., Atlanta, Georgia 30322, USA.
| | - Anna Fabiszewski de Aceituno
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, 1518 Clifton Road N.E., Atlanta, Georgia 30322, USA
| | - Lee-Ann Jaykus
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, 339-A Schaub Hall, Raleigh, North Carolina 27695, USA
| | - Santos García
- Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apostado Postal 124-F, San Nicolás, Nuevo León 66451, México
| | - Juan Leon
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, 1518 Clifton Road N.E., Atlanta, Georgia 30322, USA
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Vonasek E, Nitin N. Influence of Vacuum Cooling on Escherichia coli O157:H7 Infiltration in Fresh Leafy Greens via a Multiphoton-Imaging Approach. Appl Environ Microbiol 2016; 82:106-15. [PMID: 26475109 PMCID: PMC4702619 DOI: 10.1128/aem.02327-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 10/12/2015] [Indexed: 11/20/2022] Open
Abstract
Microbial pathogen infiltration in fresh leafy greens is a significant food safety risk factor. In various postharvest operations, vacuum cooling is a critical process for maintaining the quality of fresh produce. The overall goal of this study was to evaluate the risk of vacuum cooling-induced infiltration of Escherichia coli O157:H7 into lettuce using multiphoton microscopy. Multiphoton imaging was chosen as the method to locate E. coli O157:H7 within an intact lettuce leaf due to its high spatial resolution, low background fluorescence, and near-infrared (NIR) excitation source compared to those of conventional confocal microscopy. The variables vacuum cooling, surface moisture, and leaf side were evaluated in a three-way factorial study with E. coli O157:H7 on lettuce. A total of 188 image stacks were collected. The images were analyzed for E. coli O157:H7 association with stomata and E. coli O157:H7 infiltration. The quantitative imaging data were statistically analyzed using analysis of variance (ANOVA). The results indicate that the low-moisture condition led to an increased risk of microbial association with stomata (P < 0.05). Additionally, the interaction between vacuum cooling levels and moisture levels led to an increased risk of infiltration (P < 0.05). This study also demonstrates the potential of multiphoton imaging for improving sensitivity and resolution of imaging-based measurements of microbial interactions with intact leaf structures, including infiltration.
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Affiliation(s)
- Erica Vonasek
- Department of Biological and Agricultural Engineering, University of California, Davis, Davis, California, USA
| | - Nitin Nitin
- Department of Biological and Agricultural Engineering, University of California, Davis, Davis, California, USA Department of Food Science & Technology, University of California, Davis, Davis, California, USA
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33
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Weller D, Wiedmann M, Strawn LK. Spatial and Temporal Factors Associated with an Increased Prevalence of Listeria monocytogenes in Spinach Fields in New York State. Appl Environ Microbiol 2015; 81:6059-69. [PMID: 26116668 PMCID: PMC4551256 DOI: 10.1128/aem.01286-15] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Accepted: 06/22/2015] [Indexed: 11/20/2022] Open
Abstract
While rain and irrigation events have been associated with an increased prevalence of foodborne pathogens in produce production environments, quantitative data are needed to determine the effects of various spatial and temporal factors on the risk of produce contamination following these events. This study was performed to quantify these effects and to determine the impact of rain and irrigation events on the detection frequency and diversity of Listeria species (including L. monocytogenes) and L. monocytogenes in produce fields. Two spinach fields, with high and low predicted risks of L. monocytogenes isolation, were sampled 24, 48, 72, and 144 to 192 h following irrigation and rain events. Predicted risk was a function of the field's proximity to water and roads. Factors were evaluated for their association with Listeria species and L. monocytogenes isolation by using generalized linear mixed models (GLMMs). In total, 1,492 (1,092 soil, 334 leaf, 14 fecal, and 52 water) samples were collected. According to the GLMM, the likelihood of Listeria species and L. monocytogenes isolation from soil samples was highest during the 24 h immediately following an event (odds ratios [ORs] of 7.7 and 25, respectively). Additionally, Listeria species and L. monocytogenes isolates associated with irrigation events showed significantly lower sigB allele type diversity than did isolates associated with precipitation events (P = <0.001), suggesting that irrigation water may be a point source of L. monocytogenes contamination. Small changes in management practices (e.g., not irrigating fields before harvest) may therefore reduce the risk of L. monocytogenes contamination of fresh produce.
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Affiliation(s)
- Daniel Weller
- Department of Food Science, Cornell University, Ithaca, New York, USA
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, New York, USA
| | - Laura K Strawn
- Department of Food Science, Cornell University, Ithaca, New York, USA Department of Food Science and Technology, Eastern Shore Agriculture Research and Extension Center, Virginia Tech, Painter, Virginia, USA
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Huang J, Luo Y, Nou X. Growth of Salmonella enterica and Listeria monocytogenes on Fresh-Cut Cantaloupe under Different Temperature Abuse Scenarios. J Food Prot 2015; 78:1125-31. [PMID: 26038902 DOI: 10.4315/0362-028x.jfp-14-468] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Effective cold chain management is a critical component of food safety practice. In this study, we examined the impact of commonly encountered temperature abuse scenarios on the proliferation of Salmonella enterica and Listeria monocytogenes on fresh-cut cantaloupe. Inoculated fresh-cut cantaloupe cubes were subjected to various temperature abuse conditions, and the growth of S. enterica and L. monocytogenes was determined. During 1 week of storage, Salmonella cell counts on fresh-cut cantaloupe increased by -0.26, 1.39, and 2.23 log units at 4 °C (control), 8 °C, and 12 °C (chronic temperature abuse), respectively, whereas that of L. monocytogenes increased by 0.75, 2.86, and 4.17 log units. Under intermittent temperature abuse conditions, where storage temperature fluctuated twice daily to room temperature for 30 min, Salmonella cell count increased by 2.18 log units, whereas that of L. monocytogenes increased by 1.86 log units. In contrast, terminal acute temperature abuses for 2 to 4 h resulted in upwards to 0.6 log unit for Salmonella, whereas the effect on L. monocytogenes was less significant compared with L. monocytogenes on cut cantaloupe stored at 4 °C. Significant deterioration of produce visual quality and tissue integrity, as reflected by electrolyte leakage, was also observed under various temperature abuse conditions.
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Affiliation(s)
- Jingwei Huang
- Sichuan Agricultural University, Ya'an, Sichuan 625014, People's Republic of China
| | - Yaguang Luo
- Environmental Microbial and Food Safety Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, Maryland 20705, USA
| | - Xiangwu Nou
- Environmental Microbial and Food Safety Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, Maryland 20705, USA.
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35
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Survival of Salmonella spp. on surface-inoculated forced-air cooled and hydrocooled intact strawberries, and in strawberry puree. Food Control 2015. [DOI: 10.1016/j.foodcont.2014.11.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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36
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Dobhal S, Zhang G, Gautam D, Fletcher J, Ma LM. Uneven distribution of microorganisms on the surface of field-grown cantaloupes. Food Control 2015. [DOI: 10.1016/j.foodcont.2014.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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37
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Scientific Opinion on the risk posed by pathogens in food of non-animal origin. Part 2 (Salmonellain melons). EFSA J 2014. [DOI: 10.2903/j.efsa.2014.3831] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Gautam D, Dobhal S, Payton ME, Fletcher J, Ma LM. Surface survival and internalization of salmonella through natural cracks on developing cantaloupe fruits, alone or in the presence of the melon wilt pathogen Erwinia tracheiphila. PLoS One 2014; 9:e105248. [PMID: 25147942 PMCID: PMC4141780 DOI: 10.1371/journal.pone.0105248] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 07/22/2014] [Indexed: 11/18/2022] Open
Abstract
Outbreaks of foodborne illness attributed to the consumption of Salmonella-tainted cantaloupe have occurred repeatedly, but understanding of the ecology of Salmonella on cantaloupe fruit surfaces is limited. We investigated the interactions between Salmonella enterica Poona, the plant pathogenic bacterium Erwinia tracheiphila, and cantaloupe fruit. Fruit surfaces were inoculated at the natural cracking stage by spreading S. enterica and E. tracheiphila, 20 µl at 107 cfu/ml, independently or together, over a 2×2 cm rind area containing a crack. Microbial and microscopic analyses were performed at 0, 9 and 24 days post inoculation (DPI). Even at 24 DPI (fruit maturity) S. enterica was detected on 14% and 40% of the fruit inoculated with S. enterica alone and the two-pathogen mixture, respectively. However, the population of S. enterica declined gradually after initial inoculation. E. tracheiphila, inoculated alone or together with Salmonella, caused watersoaked lesions on cantaloupe fruit; but we could not conclude in this study that S. enterica survival on the fruit surface was enhanced by the presence of those lesions. Of fruit inoculated with E. tracheiphila alone and sampled at 24 DPI, 61% had watersoaked lesions on the surface. In nearly half of those symptomatic fruits the watersoaking extended into the sub-rind mesocarp, and E. tracheiphila was recovered from that tissue in 50% of the symptomatic fruit. In this work, E. tracheiphila internalized through natural cracks on developing fruits. S. enterica was never detected in the fruit interior (ca. 2-3 mm below rind surface) under the limited conditions of our experiments, but the possibility that it, or other human pathogens that contaminate fresh produce, might also do so should be investigated under a wider range of conditions and produce types.
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Affiliation(s)
- Dhiraj Gautam
- National Institute for Microbial Forensics & Food and Agricultural Biosecurity, Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Shefali Dobhal
- National Institute for Microbial Forensics & Food and Agricultural Biosecurity, Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Mark E. Payton
- Department of Statistics, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Jacqueline Fletcher
- National Institute for Microbial Forensics & Food and Agricultural Biosecurity, Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Li Maria Ma
- National Institute for Microbial Forensics & Food and Agricultural Biosecurity, Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma, United States of America
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Martínez-Vaz BM, Fink RC, Diez-Gonzalez F, Sadowsky MJ. Enteric pathogen-plant interactions: molecular connections leading to colonization and growth and implications for food safety. Microbes Environ 2014; 29:123-35. [PMID: 24859308 PMCID: PMC4103518 DOI: 10.1264/jsme2.me13139] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 01/19/2014] [Indexed: 11/12/2022] Open
Abstract
Leafy green vegetables have been identified as a source of foodborne illnesses worldwide over the past decade. Human enteric pathogens, such as Escherichia coli O157:H7 and Salmonella, have been implicated in numerous food poisoning outbreaks associated with the consumption of fresh produce. An understanding of the mechanisms responsible for the establishment of pathogenic bacteria in or on vegetable plants is critical for understanding and ameliorating this problem as well as ensuring the safety of our food supply. While previous studies have described the growth and survival of enteric pathogens in the environment and also the risk factors associated with the contamination of vegetables, the molecular events involved in the colonization of fresh produce by enteric pathogens are just beginning to be elucidated. This review summarizes recent findings on the interactions of several bacterial pathogens with leafy green vegetables. Changes in gene expression linked to the bacterial attachment and colonization of plant structures are discussed in light of their relevance to plant-microbe interactions. We propose a mechanism for the establishment and association of enteric pathogens with plants and discuss potential strategies to address the problem of foodborne illness linked to the consumption of leafy green vegetables.
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Affiliation(s)
| | - Ryan C. Fink
- Department of Food Science and Nutrition, University of Minnesota, St Paul, MN 55108, USA
| | | | - Michael J. Sadowsky
- Biotechnology Institute, University of Minnesota, St Paul, MN 55108, USA
- Department of Soil, Water and Climate, University of Minnesota, St Paul, MN 55108, USA
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Webb CC, Davey LE, Erickson MC, Doyle MP. Evaluation of levulinic acid and sodium dodecyl sulfate as a sanitizer for use in processing Georgia-grown cantaloupes. J Food Prot 2013; 76:1767-72. [PMID: 24112578 DOI: 10.4315/0362-028x.jfp-13-057] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Freshly harvested Georgia-grown cantaloupes (Cucumis melo L. var. reticulatus cv. Athena and Atlantis) were spot inoculated with 100 μl of a five-strain mixture of Salmonella enterica serovar Poona (9 log CFU/ml) at the stem scar and on the netted rind and then subjected to no treatment (control) or a 6-min treatment (tank only) in water, 120 ppm of chlorine (pH 7.0), 1% levulinic acid plus 0.1% sodium dodecyl sulfate (SDS; pH 3.0), or 2% levulinic acid plus 0.2% SDS (pH 3.0). The log reduction for the tank-only treatments was 0.31, 0.59, 1.32, and 1.37 log CFU/g at the stem scar and 0.97, 1.59, 2.06. and 3.37 log CFU/g on the netted rind for water, chlorine, 1% levulinic acid plus 0.1% SDS, and 2% levulinic acid plus 0.2% SDS, respectively. A greater log reduction was observed for the cantaloupe surface tissue with the water, chlorine, and 2% levulinic acid plus 0.2% SDS treatments when additional sanitizer (2 ml) and brushing (to simulate cantaloupes tumbling over brushes on the processing line) were added to the dump tank treatment. The stem scar tissue reductions were 0.90, 1.69, and 1.53 log CFU/g, whereas the netted rind reductions were 1.56, 2.50, and 4.47 log CFU/g after treatment with water, chlorine, and 2% levulinic acid plus 0.2% SDS, respectively. These data suggest that 2% levulinic acid plus 0.2% SDS is effective for reducing Salmonella on the netted rind surface of cantaloupes. However, neither 2% levulinic acid plus 0.2% SDS nor 120 ppm of chlorine substantially reduced Salmonella on stem scar tissue.
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Affiliation(s)
- Cathy C Webb
- Center for Food Safety, Department of Food Science and Technology, 1109 Experiment Street, University of Georgia, Griffin, Georgia 30223, USA
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41
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McCollum JT, Cronquist AB, Silk BJ, Jackson KA, O'Connor KA, Cosgrove S, Gossack JP, Parachini SS, Jain NS, Ettestad P, Ibraheem M, Cantu V, Joshi M, DuVernoy T, Fogg NW, Gorny JR, Mogen KM, Spires C, Teitell P, Joseph LA, Tarr CL, Imanishi M, Neil KP, Tauxe RV, Mahon BE. Multistate outbreak of listeriosis associated with cantaloupe. N Engl J Med 2013; 369:944-53. [PMID: 24004121 DOI: 10.1056/nejmoa1215837] [Citation(s) in RCA: 252] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Although new pathogen-vehicle combinations are increasingly being identified in produce-related disease outbreaks, fresh produce is a rarely recognized vehicle for listeriosis. We investigated a nationwide listeriosis outbreak that occurred in the United States during 2011. METHODS We defined an outbreak-related case as a laboratory-confirmed infection with any of five outbreak-related subtypes of Listeria monocytogenes isolated during the period from August 1 through October 31, 2011. Multistate epidemiologic, trace-back, and environmental investigations were conducted, and outbreak-related cases were compared with sporadic cases reported previously to the Listeria Initiative, an enhanced surveillance system that routinely collects detailed information about U.S. cases of listeriosis. RESULTS We identified 147 outbreak-related cases in 28 states. The majority of patients (127 of 147, 86%) were 60 years of age or older. Seven infections among pregnant women and newborns and one related miscarriage were reported. Of 145 patients for whom information about hospitalization was available, 143 (99%) were hospitalized. Thirty-three of the 147 patients (22%) died. Patients with outbreak-related illness were significantly more likely to have eaten cantaloupe than were patients 60 years of age or older with sporadic illness (odds ratio, 8.5; 95% confidence interval, 1.3 to ∞). Cantaloupe and environmental samples collected during the investigation yielded isolates matching all five outbreak-related subtypes, confirming that whole cantaloupe produced by a single Colorado farm was the outbreak source. Unsanitary conditions identified in the processing facility operated by the farm probably resulted in contamination of cantaloupes with L. monocytogenes. CONCLUSIONS Raw produce, including cantaloupe, can serve as a vehicle for listeriosis. This outbreak highlights the importance of preventing produce contamination within farm and processing environments.
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Affiliation(s)
- Jeffrey T McCollum
- Epidemic Intelligence Service, Scientific Education and Professional Development Program Office, Centers for Disease Control and Prevention, Atlanta, USA.
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Kozak GK, MacDonald D, Landry L, Farber JM. Foodborne outbreaks in Canada linked to produce: 2001 through 2009. J Food Prot 2013; 76:173-83. [PMID: 23317873 DOI: 10.4315/0362-028x.jfp-12-126] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Foodborne disease outbreaks associated with fresh fruits and vegetables have been increasing in occurrence worldwide. Canada has one of the highest per capita consumption rates of fresh fruits and vegetables in the world. In this article, we review the foodborne disease outbreaks linked to produce consumption in Canada from 2001 through 2009. The 27 produce-related outbreaks included an estimated 1,549 cases of illness. Bacterial infection outbreaks represented 66% of the total. Among these, Salmonella was the most frequent agent (50% of outbreaks) followed by Escherichia coli (33%) and Shigella (17%). Cyclospora cayetanensis was the only parasite detected and was associated with seven outbreaks. Among the foodborne viruses, only hepatitis A was implicated in two outbreaks. The food vehicles most commonly implicated in outbreaks were leafy greens and herbs (26% of outbreaks), followed by seed sprouts (11%). Contamination sources and issues related to the future control of fresh produce-related foodborne disease outbreaks also are discussed.
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Affiliation(s)
- G K Kozak
- Bureau of Microbial Hazards, Health Canada, Ottawa, Ontario, Canada K1A 0K9
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Allydice-Francis K, Brown PD. Diversity of Antimicrobial Resistance and Virulence Determinants in Pseudomonas aeruginosa Associated with Fresh Vegetables. Int J Microbiol 2012; 2012:426241. [PMID: 23213336 PMCID: PMC3508576 DOI: 10.1155/2012/426241] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 10/09/2012] [Indexed: 11/18/2022] Open
Abstract
With the increased focus on healthy eating and consuming raw vegetables, this study assessed the extent of contamination of fresh vegetables by Pseudomonas aeruginosa in Jamaica and examined the antibiotic susceptibility profiles and the presence of various virulence associated determinants of P. aeruginosa. Analyses indicated that vegetables from retail markets and supermarkets were widely contaminated by P. aeruginosa; produce from markets were more frequently contaminated, but the difference was not significant. Lettuce and carrots were the most frequently contaminated vegetables, while tomatoes were the least. Pigment production (Pyoverdine, pyocyanin, pyomelanin and pyorubin), fluorescein and alginate were common in these isolates. Imipenem, gentamicin and ciprofloxacin were the most inhibitory antimicrobial agents. However, isolates were resistant or showed reduced susceptibility to ampicillin, chloramphenicol, sulphamethoxazole/trimethoprim and aztreonam, and up to 35% of the isolates were resistant to four antimicrobial agents. As many as 30% of the isolates were positive for the fpv1 gene, and 13% had multiple genes. Sixty-four percent of the isolates harboured an exoenzyme gene (exoS, exoT, exoU or exoY), and multiple exo genes were common. We conclude that P. aeruginosa is a major contaminant of fresh vegetables, which might be a source of infection for susceptible persons within the community.
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Affiliation(s)
| | - Paul D. Brown
- Biochemistry Section, Department of Basic Medical Sciences, University of the West Indies, Mona, Kingston 7, Jamaica
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Lopez-Velasco G, Sbodio A, Tomás-Callejas A, Wei P, Tan KH, Suslow TV. Assessment of root uptake and systemic vine-transport of Salmonella enterica sv. Typhimurium by melon (Cucumis melo) during field production. Int J Food Microbiol 2012; 158:65-72. [PMID: 22824339 DOI: 10.1016/j.ijfoodmicro.2012.07.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 07/02/2012] [Accepted: 07/05/2012] [Indexed: 10/28/2022]
Abstract
Among melons, cantaloupes are most frequently implicated in outbreaks and surveillance-based recalls due to Salmonella enterica. There is limited but compelling evidence that associates irrigation water quality as a significant risk of preharvest contamination of melons. However, the potential for root uptake from water and soil and subsequent systemic transport of Salmonella into melon fruit is uncharacterized. The aim of this work was to determine whether root uptake of S. enterica results in systemic transport to fruit at high doses of applied inoculum through sub-surface drip and furrow irrigation during field production of melons. Cantaloupe and honeydew were grown under field conditions, in a silt clay loam soil using standard agronomic practices for California. An attenuated S. enterica sv. Typhimurium strain was applied during furrow irrigation and, in separate plots, buried drip-emitter lines delivered the inoculum directly into the established root zone. Contamination of the water resulted in soil contamination within furrows however Salmonella was not detected on top of the beds or around melon roots of furrow-irrigated rows demonstrating absence of detectable lateral transfer across the soil profile. In contrast, positive detection of the applied isolate occurred in soil and the rhizosphere in drip injected plots; survival of Salmonella was at least 41 days. Despite high populations of the applied bacteria in the rhizosphere, after surface disinfection, internalized Salmonella was not detected in mature melon fruit (n=485). Contamination of the applied Salmonella was detected on the rind surface of melons if fruit developed in contact with soil on the sides of the inoculated furrows. Following an unusual and heavy rain event during fruit maturation, melons collected from the central area of the beds, were shown to harbor the furrow-applied Salmonella. Delivery of Salmonella directly into the peduncle, after minor puncture wounding, resulted in detection of applied Salmonella in the sub-rind tissue below the fruit abscission zone. Results indicate that Salmonella internalization from soil and vascular systemic transport to fruit is unlikely to occur from irrigation water in CA production regions, even if substantially above normal presumptive levels of contamination. Although contaminated irrigation water and subsequently soil in contact with fruit remains a concern for contamination of the external rind, results suggest an acceptable microbial indicator threshold and critical limit for the presence of Salmonella in applied water may be possible by defining appropriate microbiological standards for melon irrigation in California and regions with similar climate, soil texture, and crop management practices.
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Affiliation(s)
- Gabriela Lopez-Velasco
- Department of Plant Sciences, University of California, One Shields Avenue, Davis, CA 95616, USA
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Parker JS, Wilson RS, LeJeune JT, Rivers L, Doohan D. An expert guide to understanding grower decisions related to fresh fruit and vegetable contamination prevention and control. Food Control 2012. [DOI: 10.1016/j.foodcont.2011.12.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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46
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The effect of different processing parameters on the efficacy of commercial post-harvest washing of minimally processed spinach and shredded lettuce. Food Control 2012. [DOI: 10.1016/j.foodcont.2011.12.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Barak JD, Schroeder BK. Interrelationships of food safety and plant pathology: the life cycle of human pathogens on plants. ANNUAL REVIEW OF PHYTOPATHOLOGY 2012; 50:241-66. [PMID: 22656644 DOI: 10.1146/annurev-phyto-081211-172936] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Bacterial food-borne pathogens use plants as vectors between animal hosts, all the while following the life cycle script of plant-associated bacteria. Similar to phytobacteria, Salmonella, pathogenic Escherichia coli, and cross-domain pathogens have a foothold in agricultural production areas. The commonality of environmental contamination translates to contact with plants. Because of the chronic absence of kill steps against human pathogens for fresh produce, arrival on plants leads to persistence and the risk of human illness. Significant research progress is revealing mechanisms used by human pathogens to colonize plants and important biological interactions between and among bacteria in planta. These findings articulate the difficulty of eliminating or reducing the pathogen from plants. The plant itself may be an untapped key to clean produce. This review highlights the life of human pathogens outside an animal host, focusing on the role of plants, and illustrates areas that are ripe for future investigation.
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Affiliation(s)
- Jeri D Barak
- Department of Plant Pathology, University of Wisconsin, Madison, Wisconsin 53706, USA.
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Soon JM. Food safety perceptions and practices of selected UK fresh produce farms. QUALITY ASSURANCE AND SAFETY OF CROPS & FOODS 2012. [DOI: 10.1111/j.1757-837x.2012.00130.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Levantesi C, Bonadonna L, Briancesco R, Grohmann E, Toze S, Tandoi V. Salmonella in surface and drinking water: Occurrence and water-mediated transmission. Food Res Int 2012. [DOI: 10.1016/j.foodres.2011.06.037] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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50
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Antunes MDC, Cavaco AM. The use of essential oils for postharvest decay control. A review. FLAVOUR FRAG J 2010. [DOI: 10.1002/ffj.1986] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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