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Vegdahl AC, Baldwin WC, Schaffner DW. Growth models for Salmonella, E. coli O157:H7 and L. monocytogenes give different predictions for pathogen growth in cut leafy greens transportation, but are consistent in identifying higher risk conditions. Food Microbiol 2023; 115:104338. [PMID: 37567626 DOI: 10.1016/j.fm.2023.104338] [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: 04/04/2023] [Revised: 06/05/2023] [Accepted: 07/10/2023] [Indexed: 08/13/2023]
Abstract
Leafy greens are frequently implicated in foodborne disease outbreaks and cut-leafy greens are a food that requires time and temperature control for safety. Predictive microbiology uses mathematical models to predict the growth of bacteria based on environmental conditions. The objective of our study was to compare published square root growth models for Salmonella (n = 6), pathogenic E. coli (n = 6) and Listeria monocytogenes (n = 4) using real world transport temperature data. Data from trucks transporting fresh-cut leafy greens during cross-country shipments were used as temperature inputs to the models. Bacterial growth was computed using the temperatures from each probe in every truck over the duration of transit, which resulted in 12-18 growth predictions per truck for each model. Each model generally gave significantly different predictions than other models for the same organism. The exception was for the two Salmonella models predicting the least growth and the two Salmonella models predicting the most growth which gave predictions that were not significantly different. Although different models tended to give different predictions, their ability to rank risk by truck was generally consistent across models. While absolute risk might be dependent upon choice of model, relative risk is independent of model choice.
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Affiliation(s)
- Ann C Vegdahl
- Department of Food Science, Cornell University Geneva, NY, 14456, USA.
| | - W Clifton Baldwin
- Data Science and Strategic Analytics, Stockton University, Galloway, NJ, 08205, USA.
| | - Donald W Schaffner
- Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, NJ, 08901, USA.
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Malka SK, Park MH. Fresh Produce Safety and Quality: Chlorine Dioxide's Role. FRONTIERS IN PLANT SCIENCE 2021; 12:775629. [PMID: 35087550 PMCID: PMC8787301 DOI: 10.3389/fpls.2021.775629] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/16/2021] [Indexed: 05/03/2023]
Abstract
Maintaining microbial safety and quality of fresh fruits and vegetables are a global concern. Harmful microbes can contaminate fresh produce at any stage from farm to fork. Microbial contamination can affect the quality and shelf-life of fresh produce, and the consumption of contaminated food can cause foodborne illnesses. Additionally, there has been an increased emphasis on the freshness and appearance of fresh produce by modern consumers. Hence, disinfection methods that not only reduce microbial load but also preserve the quality of fresh produce are required. Chlorine dioxide (ClO2) has emerged as a better alternative to chlorine-based disinfectants. In this review, we discuss the efficacy of gaseous and aqueous ClO2 in inhibiting microbial growth immediately after treatment (short-term effect) versus regulating microbial growth during storage of fresh produce (long-term effect). We further elaborate upon the effects of ClO2 application on retaining or enhancing the quality of fresh produce and discuss the current understanding of the mode of action of ClO2 against microbes affecting fresh produce.
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Luu P, Chhetri VS, Janes ME, King JM, Adhikari A. Effectiveness of Aqueous Chlorine Dioxide in Minimizing Food Safety Risk Associated with Salmonella, E. coli O157:H7, and Listeria monocytogenes on Sweet Potatoes. Foods 2020; 9:foods9091259. [PMID: 32911767 PMCID: PMC7554816 DOI: 10.3390/foods9091259] [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: 08/18/2020] [Revised: 09/01/2020] [Accepted: 09/05/2020] [Indexed: 11/28/2022] Open
Abstract
Sodium hypochlorite (NaOCl) is a commonly used sanitizer in the produce industry despite its limited effectiveness against contaminated human pathogens in fresh produce. Aqueous chlorine dioxide (ClO2) is an alternative sanitizer offering a greater oxidizing potency with greater efficacy in reducing a large number of microorganisms. We investigated the effect of aqueous chlorine dioxide treatment against human pathogens, Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes seeded on sweet potatoes. Sweet potatoes were spot inoculated (4.2 to 5.7 log CFU/cm2) with multi-strain cocktails of Salmonella spp., E. coli O157:H7, and L. monocytogenes and treated for 10–30 min with 5 ppm aqueous ClO2 or water. Aqueous ClO2 treatment was significantly (p < 0.05) effective in reducing Salmonella with a reduction of 2.14 log CFU/cm2 within 20 min compared to 1.44 log CFU/cm2 for water treatment. Similar results were observed for L. monocytogenes with a 1.98 log CFU/cm2 reduction compared to 0.49 log CFU/cm2 reduction observed after 30 min treatment with aqueous ClO2 the water respectively. The maximum reduction in E. coli O157: H7 reached 2.1 Log CFU/cm2 after 20 min of treatment with aqueous ClO2. The level of the pathogens in ClO2 wash solutions, after the treatment, was below the detectable limit. While in the water wash solutions, the pathogens’ populations ranged from 3.47 to 4.63 log CFU/mL. Our study indicates that aqueous ClO2 is highly effective in controlling cross-contamination during postharvest washing of sweet potatoes.
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Zhou S, Jin T, Sheen S, Zhao G, Liu L, Juneja V, Yam K. Development of sodium chlorite and glucono delta-lactone incorporated PLA film for microbial inactivation on fresh tomato. Food Res Int 2020; 132:109067. [PMID: 32331688 DOI: 10.1016/j.foodres.2020.109067] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 02/01/2020] [Accepted: 02/02/2020] [Indexed: 11/19/2022]
Abstract
Chlorine dioxide (ClO2) is an effective disinfectant used in the sanitization of fresh produce. Glucono delta-lactone (GDL), widely used as an acidifier during food processing, can be partially hydrolyzed to become a weak acid-gluconic acid under chemical equilibrium upon dissolution in water. This study focused on the development of a novel polylactic acid (PLA) film which incorporated with sodium chlorite (NaClO2) and GDL for ClO2(g) generation. The effects of PLA amount, NaClO2 + GDL/PLA ratio, NaClO2/GDL ratio, temperature and relative humidity on the release profiles of ClO2(g) were elucidated. The storage test indicated that film efficacy was well maintained after 4 weeks of storage under ambient conditions. The microbial inactivation results revealed that ClO2(g) generated from the films reduced populations of surface-inoculated Salmonella and Escherichia coli O157:H7 from ca. 5 log CFU/tomato to undetectable level (<1 log CFU/tomato) within 2 and 4 h respectively and the complete elimination in populations of both bacterial species was maintained throughout the 14-day storage period at both 10 and 22 °C. The sensory properties of treated tomatoes were evaluated and exhibited no significant difference (p > 0.05) compared to controls except for appearance on day 14 under 22 °C storage.
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Affiliation(s)
- Siyuan Zhou
- College of Food Science, Southwest University, Chongqing 400715, PR China; U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA.
| | - Tony Jin
- U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA
| | - Shiowshuh Sheen
- U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA
| | - Guohua Zhao
- College of Food Science, Southwest University, Chongqing 400715, PR China
| | - LinShu Liu
- U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA
| | - Vijay Juneja
- U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA
| | - Kit Yam
- Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, NJ 08901, USA
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Bai J, Jeon B, Ryu S. Effective inhibition of Salmonella Typhimurium in fresh produce by a phage cocktail targeting multiple host receptors. Food Microbiol 2019; 77:52-60. [PMID: 30297056 DOI: 10.1016/j.fm.2018.08.011] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 04/13/2018] [Accepted: 08/21/2018] [Indexed: 01/12/2023]
Abstract
Salmonella contamination of fresh produce is the primary bacterial cause of a significant number of foodborne outbreaks and infections. Bacteriophages can be used as natural antibacterial agents to control foodborne pathogens. However, the rapid development of bacterial resistance to phage infection is a significant barrier to practical phage application. To overcome this problem, we developed a novel phage cocktail consisting of the three phages (BSPM4, BSP101 and BSP22A) that target different host receptors, including flagella, O-antigen and BtuB, respectively. Whole genome sequence analysis of the phages revealed that three phages do not harbor genes involved in lysogen formation or toxin production, suggesting they are safe for use as biocontrol agents in foods. In vitro treatment of the phage cocktail resulted in a significant reduction in the development of bacterial resistance. Phage cocktail treatments achieved 4.7-5.5 log CFU/cm2 reduction of viable cell number in iceberg lettuce and 4.8-5.8 log CFU/cm2 reduction in cucumber after 12 h at room temperature (25 °C). The phage cocktail exhibited good antimicrobial efficiency, suggesting that it could reduce S. Typhimurium contamination of fresh produce. The strategy of developing cocktails of phages that target multiple host receptors can be used to develop novel biocontrol agents of S. Typhimurium.
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Affiliation(s)
- Jaewoo Bai
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Byeonghwa Jeon
- School of Public Health, University of Alberta, Edmonton, AB, Canada
| | - Sangryeol Ryu
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea; Center for Food and Bioconvergence, Seoul National University, Seoul, South Korea.
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Kang JW, Kang DH. Antimicrobial efficacy of vacuum impregnation washing with malic acid applied to whole paprika, carrots, king oyster mushrooms and muskmelons. Food Control 2017. [DOI: 10.1016/j.foodcont.2017.05.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Praeger U, Herppich WB, Hassenberg K. Aqueous chlorine dioxide treatment of horticultural produce: Effects on microbial safety and produce quality–A review. Crit Rev Food Sci Nutr 2017; 58:318-333. [DOI: 10.1080/10408398.2016.1169157] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Ulrike Praeger
- Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Department Horticultural Engineering, Potsdam, Germany
| | - Werner B. Herppich
- Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Department Horticultural Engineering, Potsdam, Germany
| | - Karin Hassenberg
- Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Department Horticultural Engineering, Potsdam, Germany
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Jiang Y, Fan X, Li X, Gurtler JB, Mukhopadhyay S, Jin T. Inactivation of Salmonella Typhimurium and quality preservation of cherry tomatoes by in-package aerosolization of antimicrobials. Food Control 2017. [DOI: 10.1016/j.foodcont.2016.08.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Park SM, Kang JH, Son HJ, Oh DH, Min SC, Song KB. Combined treatments of chestnut shell extract, fumaric acid, and mild heat to inactivate foodborne pathogens inoculated on beetroot ( Beta vulgaris L.) leaves. Food Sci Biotechnol 2016; 25:1217-1220. [PMID: 30263397 PMCID: PMC6049132 DOI: 10.1007/s10068-016-0193-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 06/02/2016] [Accepted: 06/15/2016] [Indexed: 11/26/2022] Open
Abstract
To evaluate the combined treatments of chestnut shell extract (CSE), fumaric acid (FA), and mild heat (MH) on the inactivation of Escherichia coli O157:H7 and Listeria monocytogenes inoculated on beetroot leaves, samples were treated with different concentrations of CSE or FA, as well as combinations of 0.5% CSE/0.5% FA and 0.5% CSE/MH at 50°C/0.5% FA. Among the treatments, the combined treatment of CSE/MH/FA was most effective, reducing the populations of E. coli O157:H7 and L. monocytogenes on beetroot leaves by 3.18 and 3.76 log CFU/g, respectively. In addition, the initial populations of pre-existing bacteria on beetroot leaves were reduced by 2.58 log CFU/g after the combined treatment. The inactivation effect was retained during storage at 4°C for 8 days. These results indicate that the combined treatment of CSE, FA, and MH can be effective in decontamination from foodborne pathogens and improving in the microbial safety of beetroot leaves during storage.
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Affiliation(s)
- Shin-Min Park
- Department of Food Science and Technology, Chungnam National University, Daejeon, 34134 Korea
| | - Ji-Hoon Kang
- Department of Food Science and Technology, Chungnam National University, Daejeon, 34134 Korea
| | - Hyeon-Jeong Son
- Department of Food Science and Technology, Chungnam National University, Daejeon, 34134 Korea
| | - Deog-Hwan Oh
- Department of Food Science and Biotechnology, Kangwon National University, Chuncheon, Gangwon, 24341 Korea
| | - Sea Cheol Min
- Department of Food Science and Technology, Seoul Women’s University, Seoul, 01797 Korea
| | - Kyung Bin Song
- Department of Food Science and Technology, Chungnam National University, Daejeon, 34134 Korea
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11
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Yoo S, Ghafoor K, Kim S, Sun Y, Kim J, Yang K, Lee DU, Shahbaz H, Park J. Inactivation of pathogenic bacteria inoculated onto a Bacto™agar model surface using TiO2-UVC photocatalysis, UVC and chlorine treatments. J Appl Microbiol 2015; 119:688-96. [DOI: 10.1111/jam.12877] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 05/28/2015] [Accepted: 06/14/2015] [Indexed: 12/30/2022]
Affiliation(s)
- S. Yoo
- Department of Biotechnology; Yonsei University; Seoul Korea
| | - K. Ghafoor
- Department of Food Science and Nutrition; King Saud University; Riyadh Saudi Arabia
| | - S. Kim
- Department of Biotechnology; Yonsei University; Seoul Korea
| | - Y.W. Sun
- Department of Biotechnology; Yonsei University; Seoul Korea
| | - J.U. Kim
- Department of Biotechnology; Yonsei University; Seoul Korea
| | - K. Yang
- Department of Biotechnology; Yonsei University; Seoul Korea
| | - D.-U. Lee
- Department of Food Science and Technology; Chung-Ang University; Anseong Korea
| | - H.M. Shahbaz
- Department of Biotechnology; Yonsei University; Seoul Korea
| | - J. Park
- Department of Biotechnology; Yonsei University; Seoul Korea
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Hoelzer K, Pouillot R, Van Doren J, Dennis S. Reduction of Listeria monocytogenes contamination on produce – A quantitative analysis of common liquid fresh produce wash compounds. Food Control 2014. [DOI: 10.1016/j.foodcont.2014.06.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Doona CJ, Feeherry FE, Setlow P, Malkin AJ, Leighton TJ. The Portable Chemical Sterilizer (PCS), D-FENS, and D-FEND ALL: novel chlorine dioxide decontamination technologies for the military. J Vis Exp 2014:e4354. [PMID: 24998679 DOI: 10.3791/4354] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
There is a stated Army need for a field-portable, non-steam sterilizer technology that can be used by Forward Surgical Teams, Dental Companies, Veterinary Service Support Detachments, Combat Support Hospitals, and Area Medical Laboratories to sterilize surgical instruments and to sterilize pathological specimens prior to disposal in operating rooms, emergency treatment areas, and intensive care units. The following ensemble of novel, 'clean and green' chlorine dioxide technologies are versatile and flexible to adapt to meet a number of critical military needs for decontamination(6,15). Specifically, the Portable Chemical Sterilizer (PCS) was invented to meet urgent battlefield needs and close critical capability gaps for energy-independence, lightweight portability, rapid mobility, and rugged durability in high intensity forward deployments(3). As a revolutionary technological breakthrough in surgical sterilization technology, the PCS is a Modern Field Autoclave that relies on on-site, point-of-use, at-will generation of chlorine dioxide instead of steam. Two (2) PCS units sterilize 4 surgical trays in 1 hr, which is the equivalent throughput of one large steam autoclave (nicknamed "Bertha" in deployments because of its cumbersome size, bulky dimensions, and weight). However, the PCS operates using 100% less electricity (0 vs. 9 kW) and 98% less water (10 vs. 640 oz.), significantly reduces weight by 95% (20 vs. 450 lbs, a 4-man lift) and cube by 96% (2.1 vs. 60.2 ft(3)), and virtually eliminates the difficult challenges in forward deployments of repairs and maintaining reliable operation, lifting and transporting, and electrical power required for steam autoclaves.
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Affiliation(s)
| | | | - Peter Setlow
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center
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Chun HH, Song KB. Optimisation of the combined treatments of aqueous chlorine dioxide, fumaric acid and ultraviolet-C for improving the microbial quality and maintaining sensory quality of common buckwheat sprout. Int J Food Sci Technol 2013. [DOI: 10.1111/ijfs.12283] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ho Hyun Chun
- Department of Food Science and Technology; Chungnam National University; Daejeon 305-764 Korea
| | - Kyung Bin Song
- Department of Food Science and Technology; Chungnam National University; Daejeon 305-764 Korea
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Ganesh V, Hettiarachchy NS, Griffis CL, Martin EM, Ricke SC. Electrostatic spraying of food-grade organic and inorganic acids and plant extracts to decontaminate Escherichia coli O157:H7 on spinach and iceberg lettuce. J Food Sci 2012; 77:M391-6. [PMID: 22757712 DOI: 10.1111/j.1750-3841.2012.02719.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
UNLABELLED The prevalence of foodborne illnesses is continually on rise. In the U.S.A., Escherichia coli O157:H7 (E. coli) has been associated with several outbreaks in minimally processed foods. Spinach and lettuce pose higher food safety risks and recurring food recalls suggest the insufficiency of current disinfection strategies. We aimed at offering a natural antimicrobial alternative using organic acids (malic, tartaric, and lactic acids [MA, TA, and LA, respectively]) and grape seed extract (GSE) and a novel application method using electrostatic spraying to evenly distribute the antimicrobials onto produce. Spinach and lettuce samples were washed, sanitized with sodium hypochlorite solution (6.25 mL/L), dip inoculated in water containing E. coli (7.0 log CFU/mL) for 24 h, and rewashed with sterile water to remove nonadhered pathogens. The samples were sprayed electrostatically with MA, LA, and GSE alone and in combinations and for comparison, with phosphoric acid (PA) and pH controls with deionized water adjusted to 1.5/2.3/3.6 and stored at 4 °C. When combined with LA (3%), MA (3%) showed 2.1 to 4.0 log CFU/g reduction of E. coli between the days 1 and 14 on spinach and 1.1 to 2.5 log CFU/g reduction on lettuce. Treatment with PA (1.5%) and PA (1.5%)-GSE (2%) exhibited 1.1 to 2.1 log CFU/g inhibition of E. coli on spinach during the 14-d storage. Our findings demonstrated the efficacy of electrostatic spraying of MA, LA, and GSE on fresh produce to improve the safety and lower the public health burden linked to produce contamination. PRACTICAL APPLICATION Electrostatic spraying is an emerging technique that can be adopted to improve the distribution and application of antimicrobials during fresh produce sanitation. Relatively simple and quick, the process can access most/all parts of produce surface and offer protection from food pathogens. The use of malic and lactic acids with or without grape seed extract can serve as effective antimicrobials when sprayed electrostatically, lowering the risk from postcontamination issues with spinach and iceberg lettuce. This application technology can be extended to improve the commercial food safety of other produce, fruits, poultry, and meat.
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Dai X, Luo H, Jiang L, Ling L, Xue Y, Yu Z. Efficacy of Different Sanitizing Agents and Their Combination on Microbe Population and Quality of Fresh-cut Chinese Chives. J Food Sci 2012; 77:M348-53. [DOI: 10.1111/j.1750-3841.2012.02770.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Mahmoud BSM. Effects of X-ray radiation on Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica and Shigella flexneri inoculated on shredded iceberg lettuce. Food Microbiol 2010; 27:109-14. [PMID: 19913700 DOI: 10.1016/j.fm.2009.09.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 09/06/2009] [Accepted: 09/10/2009] [Indexed: 11/24/2022]
Abstract
The main goal of this investigation was to study the efficacy of X-ray doses (0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 1.5 and 2.0 kGy) on inoculated Escherichia coli O157: H7, Listeria monocytogenes, Salmonella enterica and Shigella flexneri on shredded iceberg lettuce. The second goal was to study the effect of X-ray on the inherent microflora counts and visual color of shredded iceberg lettuce during storage at 4 degrees C for 30 days. Treatment with 1.0 kGy X-ray significantly reduced the population of E. coli O157: H7, L. monocytogenes, Salmonella enterica and S. flexneri on shredded iceberg lettuce by 4.4, 4.1, 4.8 and 4.4-log CFU 5 cm(-2), respectively. Furthermore, more than a 5 log CFU reduction of E. coli O157: H7, L. monocytogenes, S. enterica and S. flexneri was achieved with 2.0 kGy X-ray. Treatment with X-ray reduced the initial microflora on iceberg lettuce and kept them significantly (p < 0.05) lower than the control during storage at 4 degrees C and 90% RH for 30 days. Treatment with X-ray did not significantly (p > 0.05) change the green color of iceberg lettuce leaves. Treatment with X-ray significantly reduced selected pathogens and inherent microorganisms on shredded iceberg lettuce leaves, which could be a good alternative to other technologies for produce (lettuce) industry.
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Affiliation(s)
- Barakat S M Mahmoud
- Coastal Research & Extension Center, Mississippi State University, 3411 Frederic St, Pascagoula, MS 39567, USA.
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