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McGeoch LJ, Hoban A, Sawyer C, Rabie H, Painset A, Browning L, Brown D, McCarthy C, Nelson A, Firme A, Pista Â, Moreno J, Martins JV, Silveira L, Machado J, Vasconcelos P, Olufon O, Inzoungou-Massanga C, Douglas A, McCormick J, Larkin L, Balasegaram S. Salmonella Saintpaul outbreak associated with cantaloupe consumption, the United Kingdom and Portugal, September to November 2023. Epidemiol Infect 2024; 152:e78. [PMID: 38705587 PMCID: PMC11106726 DOI: 10.1017/s0950268824000670] [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: 02/09/2024] [Revised: 04/12/2024] [Accepted: 04/19/2024] [Indexed: 05/07/2024] Open
Abstract
In September 2023, the UK Health Security Agency identified cases of Salmonella Saintpaul distributed across England, Scotland, and Wales, all with very low genetic diversity. Additional cases were identified in Portugal following an alert raised by the United Kingdom. Ninety-eight cases with a similar genetic sequence were identified, 93 in the United Kingdom and 5 in Portugal, of which 46% were aged under 10 years. Cases formed a phylogenetic cluster with a maximum distance of six single nucleotide polymorphisms (SNPs) and average of less than one SNP between isolates. An outbreak investigation was undertaken, including a case-control study. Among the 25 UK cases included in this study, 13 reported blood in stool and 5 were hospitalized. One hundred controls were recruited via a market research panel using frequency matching for age. Multivariable logistic regression analysis of food exposures in cases and controls identified a strong association with cantaloupe consumption (adjusted odds ratio: 14.22; 95% confidence interval: 2.83-71.43; p-value: 0.001). This outbreak, together with other recent national and international incidents, points to an increase in identifications of large outbreaks of Salmonella linked to melon consumption. We recommend detailed questioning and triangulation of information sources to delineate consumption of specific fruit varieties during Salmonella outbreaks.
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Affiliation(s)
- Luke J. McGeoch
- Field Service South-East and London, Health Protection Operations Division, UK Health Security Agency, London, UK
- Field Epidemiology Training Programme, UK Health Security Agency, London, UK
| | - Ann Hoban
- Gastrointestinal Infections and Food Safety (One Health) Division, Clinical and Public Health Group, UK Health Security Agency, London, UK
| | - Clare Sawyer
- Field Service South-East and London, Health Protection Operations Division, UK Health Security Agency, London, UK
| | - Hussein Rabie
- Gastrointestinal Infections and Food Safety (One Health) Division, Clinical and Public Health Group, UK Health Security Agency, London, UK
| | - Incident Team
- UK Health Security Agency, London, UK
- Food Standards Agency, London, UK
- Communicable Disease Surveillance Centre, Public Health Wales, Cardiff, UK
| | - Anaïs Painset
- Gastrointestinal Bacteria Reference Unit, Clinical and Public Health Group, UK Health Security Agency, London, UK
| | - Lynda Browning
- Clinical and Protecting Health Directorate, Public Health Scotland, Glasgow, UK
| | - Derek Brown
- Scottish Microbiology Reference Laboratory (SMiRL), Glasgow, UK
| | - Caitlin McCarthy
- Clinical and Protecting Health Directorate, Public Health Scotland, Glasgow, UK
| | - Andrew Nelson
- Communicable Disease Surveillance Centre, Public Health Wales, Cardiff, UK
| | - Ana Firme
- Public Health Emergencies Operations Centre, Directorate-General of Health, Lisbon, Portugal
| | - Ângela Pista
- National Reference Laboratory for Gastrointestinal Infections, Department of Infectious Diseases, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal
| | - Joana Moreno
- Directorate of Information and Analysis, Directorate-General of Health, Lisbon, Portugal
| | - João Vieira Martins
- Directorate of Information and Analysis, Directorate-General of Health, Lisbon, Portugal
| | - Leonor Silveira
- National Reference Laboratory for Gastrointestinal Infections, Department of Infectious Diseases, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal
| | - Jorge Machado
- National Reference Laboratory for Gastrointestinal Infections, Department of Infectious Diseases, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal
| | - Paula Vasconcelos
- Public Health Emergencies Operations Centre, Directorate-General of Health, Lisbon, Portugal
| | - Oluwakemi Olufon
- Rapid Investigation Team, Field Services, Health Protection Operations Division, UK Health Security Agency, London, UK
| | - Carmellie Inzoungou-Massanga
- Rapid Investigation Team, Field Services, Health Protection Operations Division, UK Health Security Agency, London, UK
| | - Amy Douglas
- Gastrointestinal Infections and Food Safety (One Health) Division, Clinical and Public Health Group, UK Health Security Agency, London, UK
| | - Jacquelyn McCormick
- Gastrointestinal Infections and Food Safety (One Health) Division, Clinical and Public Health Group, UK Health Security Agency, London, UK
| | - Lesley Larkin
- Gastrointestinal Infections and Food Safety (One Health) Division, Clinical and Public Health Group, UK Health Security Agency, London, UK
| | - Sooria Balasegaram
- Field Service South-East and London, Health Protection Operations Division, UK Health Security Agency, London, UK
- Gastrointestinal Infections and Food Safety (One Health) Division, Clinical and Public Health Group, UK Health Security Agency, London, UK
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Yamaner Ç, Sürücü N. Assessment of the Microbiological Quality and Effect of Public Health of Ready-to-Eat Salad Samples in Isparta. Foodborne Pathog Dis 2024. [PMID: 38597592 DOI: 10.1089/fpd.2024.0002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024] Open
Abstract
Salmonella spp. and Citrobacter spp. are among the microorganisms causing important foodborne outbreaks. In this study, it was tried to determine the presence and rate of Salmonella spp. and Citrobacter spp. in salad samples collected from certain regions of province of Isparta in Türkiye. A total of 50 salad samples were analyzed. Classical culture technique was used for microbiological analysis of salad samples. Suspected isolates obtained were identified using the VITEK-2 system. Although no negative visual changes were observed in the salad samples used in the study, it was determined that the number of Gram-negative microorganisms was very high and six salad samples were not suitable for public health. In 50 salad samples, 2% Salmonella and 4% Citrobacter freundii were detected. In addition, it was determined that the Salmonella strain isolated from the salad sample was resistant to three different antibiotics and Citrobacter was resistant to two different antibiotics. Salmonella spp. and Citrobacter spp. are considered very dangerous to public health because they are associated with foodborne outbreaks and can develop antibiotic resistance very quickly. Salad producers should try to reduce the possibility of microbial contamination by using different technologies.
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Affiliation(s)
- Çiğdem Yamaner
- Department of Agricultural Biotechnology, Faculty of Agriculture, Aydın Adnan Menderes University, Aydın, Turkey
| | - Nur Sürücü
- Department of Agricultural Biotechnology, Faculty of Agriculture, Isparta University of Applied Sciences, Isparta, Turkey
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Hussain PR, Rather SA, Suradkar PP, A O. Gamma irradiation treatment of minimally processed kiwi fruit to maintain physicochemical quality and prevent microbial proliferation during refrigerated storage. J FOOD PROCESS PRES 2021. [DOI: 10.1111/jfpp.15309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Peerzada R. Hussain
- Astrophysical Sciences Division Nuclear Research Laboratory Bhabha Atomic Research Centre Srinagar India
| | - Sarver A. Rather
- Astrophysical Sciences Division Nuclear Research Laboratory Bhabha Atomic Research Centre Srinagar India
| | - Prashant P. Suradkar
- Astrophysical Sciences Division Nuclear Research Laboratory Bhabha Atomic Research Centre Srinagar India
| | - Omeera A
- Department of Food Technology Faculty of Engineering and Interdisciplinary Sciences Jamia Hamdard (Hamdard University) New Delhi India
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Duarte Santos T, Badiale Furlong E. Biological contamination of the common bean ( Phaseolus vulgaris L.) and its impact on food safety. Crit Rev Food Sci Nutr 2021; 62:4998-5004. [PMID: 33543994 DOI: 10.1080/10408398.2021.1881038] [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] [Indexed: 10/22/2022]
Abstract
The occurrence of biological contaminants in common beans is a challenge for food safety, as they can affect the bean at different points in the production chain. Their presence can result in damage to the health of consumers through their direct toxic effect or by promoting nutritional deficiencies, in addition to decreasing the crop yield that has an economic impact. In this article, the information available in the literature on the occurrence of biological contaminants in the common bean (Phaseolus vulgaris L.) was organized to identify the main risks to food safety due to biological contamination. Research showed that many studies investigated the effects of microbial contaminants during the farming and harvested of beans and that some strategies have been used to avoid losses. The presence of toxigenic fungi and some mycotoxins have also been reported, indicating that common beans may carry thermostable toxic residues, directly impacting human health. Further studies are needed to identify the role of microorganisms in determining the quality of common beans and to estimate their risks to food safety. HighlightsBeans can be contaminated by biological agents.Plants infected with parasites may be highly susceptible to other contaminants.Micotoxicologic contamination is less prevalent in beans than other grains.There are strategies to decrease the risk of bacterial contamination in beans.
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Affiliation(s)
- Thaisa Duarte Santos
- Laboratório de Micotoxinas e Ciência de Alimentos (LAMCA), Escola de Quíımica e Alimentos, Universidade Federal do Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil
| | - Eliana Badiale Furlong
- Laboratório de Micotoxinas e Ciência de Alimentos (LAMCA), Escola de Quíımica e Alimentos, Universidade Federal do Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil
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Whole-Genome-Based Survey for Polyphyletic Serovars of Salmonella enterica subsp. enterica Provides New Insights into Public Health Surveillance. Int J Mol Sci 2020; 21:ijms21155226. [PMID: 32718035 PMCID: PMC7432358 DOI: 10.3390/ijms21155226] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/07/2020] [Accepted: 07/17/2020] [Indexed: 02/06/2023] Open
Abstract
Serotyping has traditionally been considered the basis for surveillance of Salmonella, but it cannot distinguish distinct lineages sharing the same serovar that vary in host range, pathogenicity and epidemiology. However, polyphyletic serovars have not been extensively investigated. Public health microbiology is currently being transformed by whole-genome sequencing (WGS) data, which promote the lineage determination using a more powerful and accurate technique than serotyping. The focus in this study is to survey and analyze putative polyphyletic serovars. The multi-locus sequence typing (MLST) phylogenetic analysis identified four putative polyphyletic serovars, namely, Montevideo, Bareilly, Saintpaul, and Muenchen. Whole-genome-based phylogeny and population structure highlighted the polyphyletic nature of Bareilly and Saintpaul and the multi-lineage nature of Montevideo and Muenchen. The population of these serovars was defined by extensive genetic diversity, the open pan genome and the small core genome. Source niche metadata revealed putative existence of lineage-specific niche adaptation (host-preference and environmental-preference), exhibited by lineage-specific genomic contents associated with metabolism and transport. Meanwhile, differences in genetic profiles relating to virulence and antimicrobial resistance within each lineage may contribute to pathogenicity and epidemiology. The results also showed that recombination events occurring at the H1-antigen loci may be an important reason for polyphyly. The results presented here provide the genomic basis of simple, rapid, and accurate identification of phylogenetic lineages of these serovars, which could have important implications for public health.
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Machado-Moreira B, Richards K, Brennan F, Abram F, Burgess CM. Microbial Contamination of Fresh Produce: What, Where, and How? Compr Rev Food Sci Food Saf 2019; 18:1727-1750. [PMID: 33336968 DOI: 10.1111/1541-4337.12487] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 06/07/2019] [Accepted: 07/10/2019] [Indexed: 01/02/2023]
Abstract
Promotion of healthier lifestyles has led to an increase in consumption of fresh produce. Such foodstuffs may expose consumers to increased risk of foodborne disease, as often they are not subjected to processing steps to ensure effective removal or inactivation of pathogenic microorganisms before consumption. Consequently, reports of ready-to-eat fruit and vegetable related disease outbreak occurrences have increased substantially in recent years, and information regarding these events is often not readily available. Identifying the nature and source of microbial contamination of these foodstuffs is critical for developing appropriate mitigation measures to be implemented by food producers. This review aimed to identify the foodstuffs most susceptible to microbial contamination and the microorganisms responsible for disease outbreaks from information available in peer-reviewed scientific publications. A total of 571 outbreaks were identified from 1980 to 2016, accounting for 72,855 infections and 173 deaths. Contaminated leafy green vegetables were responsible for 51.7% of reported outbreaks. Contaminated soft fruits caused 27.8% of infections. Pathogenic strains of Escherichia coli and Salmonella, norovirus, and hepatitis A accounted for the majority of cases. Large outbreaks resulted in particular biases such as the observation that contaminated sprouted plants caused 31.8% of deaths. Where known, contamination mainly occurred via contaminated seeds, water, and contaminated food handlers. There is a critical need for standardized datasets regarding all aspects of disease outbreaks, including how foodstuffs are contaminated with pathogenic microorganisms. Providing food business operators with this knowledge will allow them to implement better strategies to improve safety and quality of fresh produce.
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Affiliation(s)
- Bernardino Machado-Moreira
- Teagasc Food Research Centre, Ashtown, Dublin, Ireland.,Functional Environmental Microbiology, National Univ. of Ireland Galway, Galway, Ireland
| | - Karl Richards
- Teagasc Johnstown Castle Environmental Research Centre, Wexford, Ireland
| | - Fiona Brennan
- Teagasc Johnstown Castle Environmental Research Centre, Wexford, Ireland
| | - Florence Abram
- Functional Environmental Microbiology, National Univ. of Ireland Galway, Galway, Ireland
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7
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Berrios-Rodriguez A, Olanya OM, Annous BA, Cassidy JM, Orellana L, Niemira BA. Survival of Salmonella Typhimurium on soybean sprouts following treatments with gaseous chlorine dioxide and biocontrol Pseudomonas bacteria. Food Sci Biotechnol 2017; 26:513-520. [PMID: 30263573 PMCID: PMC6049429 DOI: 10.1007/s10068-017-0071-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 12/20/2016] [Accepted: 12/28/2016] [Indexed: 10/19/2022] Open
Abstract
Control of Salmonella Typhimurium on sprouts is crucial for food and consumer safety. In this study, natural microflora on soybean seed was assessed and effects of gaseous chlorine dioxide (ClO2) and biocontrol Pseudomonas on the survival of S. Typhimurium on soybean sprouts were evaluated. Sprouts were dip-inoculated with S. Typhimurium prior to the application of the biocontrol (P. chlororaphis and P. fluorescens). After inoculation with S. Typhimurium, the sprouts were treated with ClO2 at 0.4 mg/L for 1 h (90% R.H., 13°C). Pseudomonas strains and Salmonella were recovered on Pseudomonas Agar F (PAF) and xylose lysine tergitol-4 (XLT-4) media, respectively. Pseudomonas strains reduced Salmonella by <1 log colony forming units (CFU)/g of sprouts, whereas S. Typhimurium on soybean sprouts was reduced from 2.55 to 5.35 logs CFU/g by ClO2. Gaseous ClO2 treatment reduced S. Typhimurium by 3.90 (0 h), 4.47 (24 h), and 3.61 log CFU/g (168 h). It was concluded that ClO2 and biocontrol treatment can enhance sprout safety.
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Affiliation(s)
| | - Ocen M. Olanya
- USDA-ARS, Eastern Regional Research Center, Food Safety & Intervention Technology Research Unit, 600 E. Mermaid Lane, Wyndmoor, PA 19038 USA
| | - Bassam A. Annous
- USDA-ARS, Eastern Regional Research Center, Food Safety & Intervention Technology Research Unit, 600 E. Mermaid Lane, Wyndmoor, PA 19038 USA
| | - Jennifer M. Cassidy
- USDA-ARS, Eastern Regional Research Center, Food Safety & Intervention Technology Research Unit, 600 E. Mermaid Lane, Wyndmoor, PA 19038 USA
| | - Lynette Orellana
- Department of Food and Industrial Microbiology, University of Puerto Rico, Mayaguez, Puerto Rico
| | - Brendan A. Niemira
- USDA-ARS, Eastern Regional Research Center, Food Safety & Intervention Technology Research Unit, 600 E. Mermaid Lane, Wyndmoor, PA 19038 USA
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9
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Sadler-Reeves L, Aird H, de Pinna E, Elviss N, Fox A, Kaye M, Jorgensen F, Lane C, Willis C, McLauchlin J. The occurrence of Salmonella
in raw and ready-to-eat bean sprouts and sprouted seeds on retail sale in England and Northern Ireland. Lett Appl Microbiol 2016; 62:126-9. [DOI: 10.1111/lam.12530] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/13/2015] [Accepted: 11/19/2015] [Indexed: 11/30/2022]
Affiliation(s)
- L. Sadler-Reeves
- Public Health England Food Water and Environmental Microbiology Laboratory Porton; Porton Down; Salisbury UK
| | - H. Aird
- Public Health England Food Water and Environmental Microbiology Laboratory York; York UK
| | - E. de Pinna
- Public Health England Gastrointestinal Bacteria Reference Unit; Public Health England, Colindale; London UK
| | - N. Elviss
- Public Health England Food Water and Environmental Microbiology Laboratory London; London UK
| | - A. Fox
- Public Health England Food Water and Environmental Microbiology Laboratory Preston; Royal Preston Hospital; Preston UK
| | - M. Kaye
- Public Health England Food Water and Environmental Microbiology Laboratory Birmingham; Good Hope Hospital; Sutton Coldfield UK
| | - F. Jorgensen
- Public Health England Food Water and Environmental Microbiology Laboratory Porton; Porton Down; Salisbury UK
| | - C. Lane
- Gastrointestinal, Emerging and Zoonotic Infections Department; Public Health England, Colindale; London UK
| | - C. Willis
- Public Health England Food Water and Environmental Microbiology Laboratory Porton; Porton Down; Salisbury UK
| | - J. McLauchlin
- Food Water and Environmental Microbiology Services; Public Health England; London UK
- Institute of Infection and Global Health; University of Liverpool; Liverpool UK
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10
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Hayford AE, Brown EW, Zhao S, Mammel MK, Gangiredla J, Abbott JW, Friedman SL, Ayers SL, Lewis JL, Lacher DW, McDermott P, Elkins CA. Genetic and resistance phenotypic subtyping of Salmonella Saintpaul isolates from various food sources and humans: Phylogenetic concordance in combinatory analyses. INFECTION GENETICS AND EVOLUTION 2015; 36:92-107. [PMID: 26299886 DOI: 10.1016/j.meegid.2015.08.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 08/10/2015] [Accepted: 08/18/2015] [Indexed: 10/23/2022]
Abstract
Bacterial pathogen subtyping for public health traceback of foodborne outbreaks has increasingly produced a number of disparate molecular techniques of varying resolution. Here, we bridge the molecular divide across three methodologies, transform data types for cross-comparison, and test phylogenetic concordance. Single nucleotide polymorphism (SNP) discovery was combined with pulsed-field gel electrophoresis (PFGE) and antimicrobial susceptibility profiles for identifying and differentiating 183 strains of closely related Salmonella enterica serovar Saintpaul isolates from retail meats, produce-associated outbreaks, and clinical sources. Fifty-six SNPs across 30 different genes were identified by comparative genomic analysis. These SNPs stratified general, monophyletic S. Saintpaul serovar specific signatures down to informative strain-specific markers. This SNP panel resulted in 17 distinct genotypes that, in concert with standard PFGE profiling, generated additional discriminatory power among clonal swarms of isolates when the data were transformed into a cross-comparable binary format. In a limited number of cases, antimicrobial susceptibility profiles (ASP) provided additional attributes for some strains when combined similarly. However, as expected from presumably acquired elements, resistant and susceptible populations produced some conflicting signals in most clonal complexes but they remained largely undisruptive to the general concordance. Taken in concert together, the three datasets (SNPs, PFGE,ASP) yielded a matrix of 156 independent phylogenetic characters that were statistically evaluated and found to be largely congruent, resulting in a consistently structured, non-homoplastic, phylogenetic signal and tree topology.
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Affiliation(s)
- Alice E Hayford
- Division of Molecular Biology, Center for Food Safety Applied Nutrition, U. S. Food and Drug Administration, Laurel, MD 20708, USA.
| | - Eric W Brown
- Division of Microbiology, Center for Food Safety and Applied Nutrition, U S Food and Drug Administration, College Park, MD 20740, USA
| | - Shaohua Zhao
- Division of Animal and Food Microbiology, Center for Food Safety and Applied Nutrition, U. S. Food and Drug Administration, Laurel, MD 20708, USA
| | - Mark K Mammel
- Division of Molecular Biology, Center for Food Safety Applied Nutrition, U. S. Food and Drug Administration, Laurel, MD 20708, USA
| | - Jayanthi Gangiredla
- Division of Molecular Biology, Center for Food Safety Applied Nutrition, U. S. Food and Drug Administration, Laurel, MD 20708, USA
| | - Jason W Abbott
- Division of Animal and Food Microbiology, Center for Food Safety and Applied Nutrition, U. S. Food and Drug Administration, Laurel, MD 20708, USA
| | - Sharon L Friedman
- Division of Animal and Food Microbiology, Center for Food Safety and Applied Nutrition, U. S. Food and Drug Administration, Laurel, MD 20708, USA
| | - Sherry L Ayers
- Division of Animal and Food Microbiology, Center for Food Safety and Applied Nutrition, U. S. Food and Drug Administration, Laurel, MD 20708, USA
| | - Jada L Lewis
- Division of Molecular Biology, Center for Food Safety Applied Nutrition, U. S. Food and Drug Administration, Laurel, MD 20708, USA
| | - David W Lacher
- Division of Molecular Biology, Center for Food Safety Applied Nutrition, U. S. Food and Drug Administration, Laurel, MD 20708, USA
| | - Patrick McDermott
- National Antimicrobial Resistance Monitoring System,Center for Veterinary Medicine, U. S. Food Drug Administration, Laurel, MD 20708, USA
| | - Christopher A Elkins
- Division of Molecular Biology, Center for Food Safety Applied Nutrition, U. S. Food and Drug Administration, Laurel, MD 20708, USA
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12
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Gu G, Cevallos-Cevallos JM, Vallad GE, van Bruggen AHC. Organically managed soils reduce internal colonization of tomato plants by Salmonella enterica serovar Typhimurium. PHYTOPATHOLOGY 2013; 103:381-388. [PMID: 23506364 DOI: 10.1094/phyto-04-12-0072-fi] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A two-phase experiment was conducted twice to investigate the effects of soil management on movement of Salmonella enterica Typhimurium in tomato plants. In the first phase, individual leaflets of 84 tomato plants grown in conventional or organic soils were dip inoculated two to four times before fruiting with either of two Salmonella Typhimurium strains (10(9) CFU/ml; 0.025% [vol/vol] Silwet L-77). Inoculated and adjacent leaflets were tested for Salmonella spp. densities for 30 days after each inoculation. Endophytic bacterial communities were characterized by polymerase chain reaction denaturing gradient gel electrophoresis before and after inoculation. Fruit and seed were examined for Salmonella spp. incidence. In phase 2, extracted seed were planted in conventional soil, and contamination of leaves and fruit of the second generation was checked. More Salmonella spp. survived in inoculated leaves on plants grown in conventional than in organic soil. The soil management effect on Salmonella spp. survival was confirmed for tomato plants grown in two additional pairs of soils. Endophytic bacterial diversities of tomato plants grown in conventional soils were significantly lower than those in organic soils. All contaminated fruit (1%) were from tomato plants grown in conventional soil. Approximately 5% of the seed from infested fruit were internally contaminated. No Salmonella sp. was detected in plants grown from contaminated seed.
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Affiliation(s)
- Ganyu Gu
- Department of Plant Pathology, University of Florida, Gainseville, FL, USA
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13
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Olaimat AN, Holley RA. Factors influencing the microbial safety of fresh produce: A review. Food Microbiol 2012; 32:1-19. [DOI: 10.1016/j.fm.2012.04.016] [Citation(s) in RCA: 582] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 02/22/2012] [Accepted: 04/26/2012] [Indexed: 11/25/2022]
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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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15
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Fernandes F, Rodrigues S. Ultrasound Applications in Fruit Processing. ADVANCES IN FRUIT PROCESSING TECHNOLOGIES 2012. [DOI: 10.1201/b12088-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Steenackers H, Hermans K, Vanderleyden J, De Keersmaecker SC. Salmonella biofilms: An overview on occurrence, structure, regulation and eradication. Food Res Int 2012. [DOI: 10.1016/j.foodres.2011.01.038] [Citation(s) in RCA: 314] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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17
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Scientific Opinion on the risk posed by Shiga toxin-producingEscherichia coli(STEC) and other pathogenic bacteria in seeds and sprouted seeds. EFSA J 2011. [DOI: 10.2903/j.efsa.2011.2424] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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18
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Gu G, Hu J, Cevallos-Cevallos JM, Richardson SM, Bartz JA, van Bruggen AHC. Internal colonization of Salmonella enterica serovar Typhimurium in tomato plants. PLoS One 2011; 6:e27340. [PMID: 22096553 PMCID: PMC3212569 DOI: 10.1371/journal.pone.0027340] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 10/14/2011] [Indexed: 01/04/2023] Open
Abstract
Several Salmonella enterica outbreaks have been traced back to contaminated tomatoes. In this study, the internalization of S. enterica Typhimurium via tomato leaves was investigated as affected by surfactants and bacterial rdar morphotype, which was reported to be important for the environmental persistence and attachment of Salmonella to plants. Surfactants, especially Silwet L-77, promoted ingress and survival of S. enterica Typhimurium in tomato leaves. In each of two experiments, 84 tomato plants were inoculated two to four times before fruiting with GFP-labeled S. enterica Typhimurium strain MAE110 (with rdar morphotype) or MAE119 (without rdar). For each inoculation, single leaflets were dipped in 10(9) CFU/ml Salmonella suspension with Silwet L-77. Inoculated and adjacent leaflets were tested for Salmonella survival for 3 weeks after each inoculation. The surface and pulp of ripe fruits produced on these plants were also examined for Salmonella. Populations of both Salmonella strains in inoculated leaflets decreased during 2 weeks after inoculation but remained unchanged (at about 10(4) CFU/g) in week 3. Populations of MAE110 were significantly higher (P<0.05) than those of MAE119 from day 3 after inoculation. In the first year, nine fruits collected from one of the 42 MAE119 inoculated plants were positive for S. enterica Typhimurium. In the second year, Salmonella was detected in adjacent non-inoculated leaves of eight tomato plants (five inoculated with strain MAE110). The pulp of 12 fruits from two plants inoculated with MAE110 was Salmonella positive (about 10(6) CFU/g). Internalization was confirmed by fluorescence and confocal laser microscopy. For the first time, convincing evidence is presented that S. enterica can move inside tomato plants grown in natural field soil and colonize fruits at high levels without inducing any symptoms, except for a slight reduction in plant growth.
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Affiliation(s)
- Ganyu Gu
- Emerging Pathogens Institute and Department of Plant Pathology, University of Florida, Gainesville, Florida, United States of America.
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Berger CN, Sodha SV, Shaw RK, Griffin PM, Pink D, Hand P, Frankel G. Fresh fruit and vegetables as vehicles for the transmission of human pathogens. Environ Microbiol 2010; 12:2385-97. [DOI: 10.1111/j.1462-2920.2010.02297.x] [Citation(s) in RCA: 581] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Almualla NA, Laleye LC, Abushelaibi AA, Al-Qassemi RA, Wasesa AA, Baboucarr J. Aspects of the microbiological quality and safety of ready-to-eat foods in Sharjah supermarkets in the United Arab Emirates. J Food Prot 2010; 73:1328-31. [PMID: 20615347 DOI: 10.4315/0362-028x-73.7.1328] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Over the last few years, ready-to-eat (RTE) foods have become popular in grocery stores all over the world. This study was conducted to evaluate the microbiological safety and shelf life of some RTE salads sold in supermarkets in Sharjah Emirate, United Arab Emirates. Samples of four RTE salads, tabbouleh, hummus, Greek salad, and coleslaw, were obtained from supermarkets and examined for aerobic bacteria, Escherichia coli, Staphylococcus aureus, Salmonella, and Listeria monocytogenes. The results indicated significant differences (P < or = 0.05) for the aerobic bacteria count among the RTE salad types. In tabbouleh, hummus, Greek salad, and coleslaw, E. coli counts of 0.9, 0.50, 0.27, and 0.25 log most probable number (MPN)/g and total aerobic bacterial plate counts of 3.57, 2.71, 2.76, and 2.52 log CFU/g, respectively, were found after preparation (day 0). At day 0, all RTE salads tested except tabbouleh contained an acceptable count of total bacteria, but the aerobic bacteria count for all the RTE salads increased rapidly during storage from day 2 to day 6, regardless of the storage temperature (5, 25, and 40 degrees C). Twenty percent of all samples contained E. coli, although the numbers were as low as 1 log MPN/g. No S. aureus, L. monocytogenes, or Salmonella serotypes were detected in any of the RTE salads tested in this study.
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Affiliation(s)
- Najla A Almualla
- Food Control Laboratory, Sharjah Municipality, Sharjah, United Arab Emirates
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A multi-state outbreak of Salmonella Saintpaul in Australia associated with cantaloupe consumption. Epidemiol Infect 2009; 137:367-74. [PMID: 18559128 DOI: 10.1017/s0950268808000861] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A multi-state outbreak of Salmonella enterica serovar Saintpaul infection occurred in Australia during October 2006. A case-control study conducted in three affected jurisdictions, New South Wales, Victoria and Australian Capital Territory, included 36 cases with the outbreak-specific strain of S. Saintpaul identified by multiple locus variable-number tandem repeat analysis (MLVA) in a faecal specimen and 106 controls. Consumption of cantaloupe (rockmelon) was strongly associated with illness (adjusted OR 23.9 95%, 95% CI 5.1-112.4). S. Saintpaul, with the outbreak MLVA profile, was detected on the skin of two cantaloupes obtained from an implicated retailer. Trace-back investigations did not identify the specific source of the outbreak strain of S. Saintpaul, but multiple Salmonella spp. were detected in environmental samples from farms and packing plants investigated during the trace-back operation. Cantaloupe production and processing practices pose a potential public health threat requiring regulatory and community educational interventions.
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Xi M, Zheng J, Zhao S, Brown EW, Meng J. An enhanced discriminatory pulsed-field gel electrophoresis scheme for subtyping Salmonella serotypes Heidelberg, Kentucky, SaintPaul, and Hadar. J Food Prot 2008; 71:2067-72. [PMID: 18939754 DOI: 10.4315/0362-028x-71.10.2067] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Conventional pulsed-field gel electrophoresis (PFGE) protocols, used extensively as a successful approach for subtyping many salmonellae, may be inadequate for discriminating strains sharing levels of homogeneity within the same serotype. Four additional restriction enzymes (SpeI, PacI, SfiI, and NotI), in addition to XbaI and BlnI, were used in PFGE typing of 33 Salmonella Heidelberg, 27 Salmonella Kentucky, 27 Salmonella SaintPaul, and 27 Salmonella Hadar isolates that were recovered from poultry and porcine retail meats from different states of the United States. A dendrogram derived from the combined analysis of six enzymes was highly discriminatory with a Simpson index of diversity value of over 0.950. The ratio of nodes to isolates was more than 0.75 with an average of fewer than three isolates in each polytomy for all four serotypes. Two three-enzyme combinations, SpeI/NotI/SfiI for Salmonella Heidelberg and Salmonella Hadar, and SpeI/BlnI/SfiI for Salmonella Kentucky and Salmonella SaintPaul, were found to have comparable discriminatory abilities of differentiating isolates of these Salmonella serotypes with the six-enzyme combination. The enhanced discriminatory PFGE-based subtyping scheme can be used effectively for the differentiation of strains of the four Salmonella serotypes. The findings also highlight PFGE analysis as a continued essential and informative subtyping method for source tracking and outbreak investigations of these and other Salmonella pathogens.
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Affiliation(s)
- Meili Xi
- College of Food Science and Engineering, Northwest A&F University, Shaanxi, China
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JALALI MOHAMMAD, ABEDI DARYOUSH, POURBAKHSH SEYEDALI, GHOUKASIN KARINE. PREVALENCE OFSALMONELLASPP. IN RAW AND COOKED FOODS IN ISFAHAN-IRAN. J Food Saf 2008. [DOI: 10.1111/j.1745-4565.2008.00122.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
In recent years the importance of prepared salads as potential vehicles of gastrointestinal infection has been highlighted by several large outbreaks both nationally and across international boundaries. Between 1992 and 2006, 2274 foodborne general outbreaks of infectious intestinal disease were reported in England and Wales, of which 4% were associated with the consumption of prepared salads. In total, 3434 people were affected, with 66 hospitalizations and one death reported. The attribution of prepared salad types and pathogens among prepared salad associated outbreaks are presented and discussed. Findings from UK studies on salad vegetables, fruit and mixed salads from 1995 to 2007 (21 247 samples) indicate that most bacteria of concern with regard to human health are relatively rare in these products (98.6% of satisfactory quality); however, outbreaks of salmonellosis were uncovered associated with bagged salad leaves and fresh herbs during two such studies. Although it is known that fresh salad vegetables, herbs or fruit may become contaminated from environmental sources, only in recent years has the association of foods of nonanimal origin, such as salad vegetables, with foodborne illness become evident and recurrent, demonstrating that major health problems can arise from consumption of contaminated prepared salads if hygiene practices breakdown.
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Affiliation(s)
- C L Little
- Health Protection Agency, Department of Gastrointestinal, Emerging and Zoonotic Infections, HPA Centre for Infections, London, UK.
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Salmonella infections associated with mung bean sprouts: epidemiological and environmental investigations. Epidemiol Infect 2008; 137:357-66. [DOI: 10.1017/s0950268808000411] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
SUMMARYWe investigated an outbreak of Salmonella Enteritidis (SE) infections linked to raw mung bean sprouts in 2000 with two case-control studies and reviewed six similar outbreaks that occurred in 2000–2002. All outbreaks were due to unusual phage types (PT) of SE and occurred in the United States (PT 33, 1, and 913), Canada (PT 11b and 913), and The Netherlands (PT 4b). PT 33 was in the spent irrigation water and a drain from one sprout grower. None of the growers disinfected seeds at recommended concentrations. Only two growers tested spent irrigation water; neither discarded the implicated seed lots after receiving a report of Salmonella contamination. We found no difference in the growth of SE and Salmonella Newport on mung beans. Mung bean sprout growers should disinfect seeds, test spent irrigation water, and discontinue the use of implicated seed lots when pathogens are found. Laboratories should report confirmed positive Salmonella results from sprout growers to public health authorities.
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Whipps JM, Hand P, Pink DA, Bending GD. Chapter 7 Human Pathogens and the Phyllosphere. ADVANCES IN APPLIED MICROBIOLOGY 2008; 64:183-221. [DOI: 10.1016/s0065-2164(08)00407-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Jin HH, Lee SY. Combined Effect of Aqueous Chlorine Dioxide and Modified Atmosphere Packaging on Inhibiting Salmonella Typhimurium and Listeria monocytogenes in Mungbean Sprouts. J Food Sci 2007; 72:M441-5. [DOI: 10.1111/j.1750-3841.2007.00555.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Liu B, Schaffner DW. Mathematical modeling and assessment of microbial migration during the sprouting of alfalfa in trays in a nonuniformly contaminated seed batch using Enterobacter aerogenes as a surrogate for Salmonella Stanley. J Food Prot 2007; 70:2602-5. [PMID: 18044441 DOI: 10.4315/0362-028x-70.11.2602] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Raw seed sprouts have been implicated in several food poisoning outbreaks in the past 10 years. The U.S. Food and Drug Administration recommends that sprout growers use interventions (such as testing of spent irrigation water) to control the presence of pathogens in the finished product. During the sprouting process, initially low concentrations of pathogen may increase, and contamination may spread within a batch of sprouting seeds. A model of pathogen growth as a function of time and distance from the contamination spot during the sprouting of alfalfa in trays has been developed with Enterobacter aerogenes. The probability of detecting contamination was assessed by logistic regression at various time points and distances by sampling from sprouts or irrigation water. Our results demonstrate that microbial populations and possibility of detection were greatly reduced at distances of > or = 20 cm from the point of contamination in a seed batch during tray sprouting; however, the probability of detecting microbial contamination at distances less than 10 cm from the point of inoculation was almost 100% at the end of the sprouting process. Our results also show that sampling irrigation water, especially large volumes of water, is highly effective at detecting contamination: by collecting 100 ml of irrigation water for membrane filtration, the probability of detection was increased by three to four times during the first 6 h of seed germination. Our findings have quantified the degree to which a small level of contamination will spread throughout a tray of sprouting alfalfa seeds and subsequently be detected by either sprout or irrigation water sampling.
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Affiliation(s)
- Bin Liu
- Food Risk Analysis Initiative, Rutgers University, 65 Dudley Road, New Brunswick, New Jersey 08901-8520, USA
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Barak JD, Jahn CE, Gibson DL, Charkowski AO. The role of cellulose and O-antigen capsule in the colonization of plants by Salmonella enterica. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2007; 20:1083-91. [PMID: 17849711 DOI: 10.1094/mpmi-20-9-1083] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Numerous salmonellosis outbreaks have been associated with vegetables, in particular sprouted seed. Thin aggregative fimbriae (Tafi), a component of the extracellular matrix responsible for multicellular behavior, are important for Salmonella enterica attachment and colonization of plants. Here, we demonstrate that the other surface polymers composing the extracellular matrix, cellulose, and O-antigen capsule also play a role in colonization of plants. Mutations in bacterial cellulose synthesis (bcsA) and O-antigen capsule assembly and translocation (yihO) reduced the ability to attach to and colonize alfalfa sprouts. A colanic acid mutant was unaffected in plant attachment or colonization. Tafi, cellulose synthesis, and O-antigen capsule, all of which contribute to attachment and colonization of plants, are regulated by AgfD, suggesting that AgfD is a key regulator for survival outside of hosts of Salmonella spp. The cellulose biosynthesis regulator adrA mutant was not affected in the ability to attach to or colonize plants; however, promoter probe assays revealed expression by cells attached to alfalfa sprouts. Furthermore, quantitative reverse-transcriptase polymerase chain reaction revealed differential expression of agfD and adrA between planktonic and plant-attached cells. In addition, there was no correlation among mutants between biofilm formation in culture and attachment to plants. Outside of animal hosts, S. enterica appears to rely on an arsenal of adhesins to persist on plants, which can act as vectors and perpetuate public health concerns.
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Affiliation(s)
- Jeri D Barak
- Produce Safety and Microbiology Research Unit, United States Department of Agriculture-Agricultural Research Service, Albany, CA 94710, USA.
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Weiss A, Hertel C, Grothe S, Ha D, Hammes WP. Characterization of the cultivable microbiota of sprouts and their potential for application as protective cultures. Syst Appl Microbiol 2007; 30:483-93. [PMID: 17512686 DOI: 10.1016/j.syapm.2007.03.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2006] [Revised: 03/20/2007] [Accepted: 03/21/2007] [Indexed: 11/26/2022]
Abstract
The microbiota of ten seeds and ready-to-eat sprouts produced thereof was characterized by bacteriological culture and denaturing gradient gel electrophoresis (DGGE) of amplified DNA fragments of the 16S rRNA gene. The predominant bacterial biota of hydroponically grown sprouts mainly consisted of enterobacteria, pseudomonades and lactic acid bacteria (LAB). For adzuki, alfalfa, mung bean, radish, sesame and wheat, the ratio of these bacterial groups changed strongly in the course of germination, whereas for broccoli, red cabbage, rye and green pea the ratio remained unchanged. Within the pseudomonades, Pseudomonas gesardii and Pseudomonas putida have been isolated and strains of the potentially pathogenic species Enterobacter cancerogenes and Pantoea agglomerans were found as part of the main microbiota on hydroponically grown sprouts. In addition to the microbiota of the whole seedlings, the microbiota of root, hypocotyl and seed leafs were examined for alfalfa, radish and mung bean sprouts. The highest and lowest total counts for aerobic bacteria were found on seed leafs and hypocotyls, respectively. On the other hand, the highest numbers for LAB on sprouts were found on the hypocotyl. When sprouting occurred under the agricultural conditions, e.g. in soil, the dominating microbiota changed from enterobacteria to pseudomonades for mung beans and alfalfa sprouts. No pathogenic enterobacteria have been isolated from these sprout types. Within the pseudomonades group, Pseudomonas jessenii and Pseudomonas brassicacearum were found as dominating species on all seedling parts from soil samples. In practical experiments, a strain of P. jessenii was found to exhibit a potential for use as protective culture, as it suppresses the growth of pathogenic enterobacteria on ready-to-eat sprouts.
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Affiliation(s)
- Alexander Weiss
- Institute of Food Technology, University of Hohenheim, Stuttgart, Germany
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Shashidhar R, Dhokane VS, Hajare SN, Sharma A, Bandekar JR. Effectiveness of Radiation Processing for Elimination of Salmonella Typhimurium from Minimally Processed Pineapple (Ananas comosus Merr.). J Food Sci 2007; 72:M98-M101. [DOI: 10.1111/j.1750-3841.2007.00300.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Liu B, Schaffner DW. Quantitative analysis of the growth of Salmonella stanley during alfalfa sprouting and evaluation of Enterobacter aerogenes as its surrogate. J Food Prot 2007; 70:316-22. [PMID: 17340864 DOI: 10.4315/0362-028x-70.2.316] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Raw seed sprouts have been implicated in several food poisoning outbreaks in the last 10 years. Few studies have included investigations of factors influencing the effectiveness of testing spent irrigation water, and in no studies to date has a nonpathogenic surrogate been identified as suitable for large-scale irrigation water testing trials. Alfalfa seeds were inoculated with Salmonella Stanley or its presumptive surrogate (nalidixic acid-resistant Enterobacter aerogenes) at three concentrations (-3, -30, and -300 CFU/g) and were then transferred into either flasks or a bench top-scale sprouting chamber. Microbial concentrations were determined in seeds, sprouts, and irrigation water at various times during a 4-day sprouting process. Data were fit to logistic regression models, and growth rates and maximum concentrations were compared using the generalized linear model procedure of SAS. No significant differences in growth rates were observed among samples taken from flasks or the chamber. Microbial concentrations in irrigation water were not significantly different from concentrations in sprout samples obtaihed at the same time. E. aerogenes concentrations were similar to those of Salmonella Stanley at corresponding time points for all three inoculum concentrations. Growth rates were also constant regardless of inoculum concentration or strain, except that lower inoculum concentrations resulted in lower final concentrations proportional to their initial concentrations. This research demonstrated that a nonpathogenic easy-to-isolate surrogate (nalidixic acid-resistant E. aerogenes) provides results similar to those obtained with Salmonella Stanley, supporting the use of this surrogate in future large-scale experiments.
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Affiliation(s)
- Bin Liu
- Food Risk Analysis Initiative, Rutgers University, New Brunswick, New Jersey 08901-8520, USA
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Muñoz M, De Ancos B, Sánchez-Moreno C, Pilar Cano M. Evaluation of chemical and physical (high-pressure and temperature) treatments to improve the safety of minimally processed mung bean sprouts during refrigerated storage. J Food Prot 2006; 69:2395-402. [PMID: 17066918 DOI: 10.4315/0362-028x-69.10.2395] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The objective of this study was to compare the effects of combined high hydrostatic pressure and temperature treatments with different chemical sanitation treatments (water, sodium hypochlorite, and hydrogen peroxide) on the microbiological properties of mung bean sprouts. In a first study, the raw product was subjected to several combined high-pressure and temperature treatments for calculating a mathematical model by a response surface methodology. The number of pressure-temperature (150 to 400 MPa; 20 to 40 degrees C) combinations was limited to 10. In addition, a model system consisting of mung bean sprout juice was inoculated with Listeria monocytogenes (CECT 4032). Microbial inactivation with this model system was also investigated by a response surface methodology. The highest aerobic mesophilic bacteria and L. monocytogenes inactivation was achieved at maximum pressure and temperature (5.5 and 1.8 log cycles, respectively). In a second study, the effect of five different processing lines on the microbial load reduction of minimally processed mung bean sprouts during refrigerated storage was studied. All treatments reduced the initial population of aerobic mesophilic bacteria and fecal coliforms, with the physical treatment of 400 MPa and 40 degrees C being the most effective, showing initial reductions of 5.8 and 7.8 log CFU/ g, respectively. Recovery of bacteria from sprouts treated under these conditions was not observed during storage. However, the sprouts that received washing treatments with water, sodium hypochlorite, and hydrogen peroxide exhibited increases in aerobic mesophilic and fecal coliform counts after 3 days of storage at 4 degrees C.
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Affiliation(s)
- Marina Muñoz
- Department of Plant Foods Science and Technology, Instituto del Frío-Consejo Superior de Investigaciones, José Antonio Novais, 10, E-28040 Madrid, Spain
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36
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Hajare SN, Dhokane VS, Shashidhar R, Saroj S, Sharma A, Bandekar JR. Radiation Processing of Minimally Processed Pineapple (Ananas comosus Merr.): Effect on Nutritional and Sensory Quality. J Food Sci 2006. [DOI: 10.1111/j.1750-3841.2006.00116.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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37
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Soylemez G, Brashears M, Smith D, Cuppett S. Microbial Quality of Alfalfa Seeds and Sprouts after a Chlorine Treatment and Packaging Modifications. J Food Sci 2006. [DOI: 10.1111/j.1365-2621.2001.tb15598.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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38
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Dhokane VS, Hajare S, Shashidhar R, Sharma A, Bandekar JR. Radiation processing to ensure safety of minimally processed carrot (Daucus carota) and cucumber (Cucumis sativus): optimization of dose for the elimination of Salmonella Typhimurium and Listeria monocytogenes. J Food Prot 2006; 69:444-8. [PMID: 16496592 DOI: 10.4315/0362-028x-69.2.444] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Minimally processed vegetables are in demand, because they offer convenience to consumers. However, these products are often unsafe because of possible contamination with pathogens, such as Salmonella, Escherichia coli O157:H7, and Shigella species. Therefore, this study was carried out to optimize the radiation dose necessary to ensure the safety of precut carrot and cucumber. Decimal reduction doses (D-values) of Salmonella Typhimurium MTCC 98 were ca. 0.164 kGy in carrot samples and 0.178 kGy in cucumber samples. D-values of Listeria monocytogenes were determined to be 0.312 and 0.345 kGy in carrot and cucumber samples, respectively. Studies of inoculated, packaged, minimally processed carrot and cucumber samples showed that treatment with a 1-kGy dose of gamma radiation eliminated up to 4 log CFU/g of Salmonella Typhimurium and 3 log CFU/g of L. monocytogenes. However, treatment with a 2-kGy dose was necessary to eliminate these pathogens by 5 log CFU/g. Storage studies showed that both Salmonella Typhimurium and L. monocytogenes were able to grow at 10 degrees C in inoculated control samples. Neither of these pathogens could be recovered from radiation-processed samples after storage for up to 8 days.
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Affiliation(s)
- V S Dhokane
- Food Technology Division, Bhabha Atomic Research Centre, Mumbai, India
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Barak JD, Sananikone K, Delwiche MJ. Comparison of primers for the detection of pathogenic Escherichia coli using real-time PCR. Lett Appl Microbiol 2005; 41:112-8. [PMID: 16033506 DOI: 10.1111/j.1472-765x.2005.01746.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To evaluate PCR primers for the detection of pathogenic Escherichia coli in a real-time PCR assay and determine their utility in produce irrigation water testing. METHODS AND RESULTS Three previously published PCR primer sets and one set designed for this study were tested for their ability to produce amplification products for several pathogenic E. coli serotypes from whole cells as template. Two of the previously published primer sets were chosen for real-time PCR detection limit determination. The coneaeA and PEH detection limit of E. coli O157:H7 was 10(0) and 10(1) CFU rxn(-1) in sterile water respectively. To detect E. coli O157:H7 in sprout irrigation water, the water required dilution due to PCR inhibitors. The detection limit of the coneaeA and PEH was 10(1) and between 10(2) and 10(3) CFU rxn(-1) in diluted sprout irrigation water respectively. CONCLUSIONS The primer set coneaeA was able to produce an amplification product from each E. coli serotype, except O128:H7 and most sensitive for real-time PCR detection of pathogenic E. coli in diluted sprout irrigation water. SIGNIFICANCE AND IMPACT OF THE STUDY The necessity of a dissociation analysis to distinguish positive samples from those with fluorescence of random dsDNA generation for real-time PCR in a complex background was established.
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Affiliation(s)
- J D Barak
- Produce Safety and Microbiology Research Unit, USDA Agricultural Research Service, Albany, CA 94710, USA.
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Singh BR, Chandra M, Agarwal R. Interaction of Salmonella enterica subspecies enterica serovar Typhimurium and mung bean (Phaseolus aureus) plants. J Food Prot 2005; 68:476-81. [PMID: 15771169 DOI: 10.4315/0362-028x-68.3.476] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The effect of Salmonella enterica subspecies enterica serovar Typhimurium, a zoonotic serovar, on mung bean (Phaseolus aureus) cultivar Pant Mung-3 plants was studied. Inoculation of mung bean seeds with Salmonella Typhimurium (7.2 x 10(5) CFU/ml) reduced sprouting rate (P < 0.07). This effect was more pronounced at higher levels of contamination. In the soil inoculated with Salmonella Typhimurium (7.2 x 10(6) CFU/g), germination was retarded and the number of defective sprouts was also significantly higher (P < 0.002). Salmonella Typhimurium grew inside germinating seeds and plant tissues and persisted in seedlings, adult plants, and harvested seedlings dried and stored at room temperature (30 degrees C) up to 45 days. Phaseolus aureus plants grown in sterile soil was resistant to Salmonella Typhimurium infection at 15 days of age and cleared Salmonella from all the aerial parts within 3 h of infection. However, Salmonella Typhimurium could be reisolated from the basal area of the stem and from soil even after 45 days of exposure to the pathogen.
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Affiliation(s)
- Bhoj Raj Singh
- National Salmonella Centre (Vet), Indian Veterinary Research Institute, Izatnagar 243 122, India.
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Abstract
Awareness is growing that fresh or minimally processed fruit and vegetables can be sources of disease-causing bacteria, viruses, protozoa, and helminths. Irrigation with poor-quality water is one way that fruit and vegetables can become contaminated with foodborne pathogens. Groundwater, surface water, and human wastewater are commonly used for irrigation. The risk of disease transmission from pathogenic microorganisms present in irrigation water is influenced by the level of contamination; the persistence of pathogens in water, in soil, and on crops; and the route of exposure. Groundwater is generally of good microbial quality, unless it is contaminated with surface runoff; human wastewater is usually of very poor microbial quality and requires extensive treatment before it can be used safely to irrigate crops; surface water is of variable microbial quality. Bacteria and protozoa tend to show the poorest survival outside a human host, whereas viruses and helminths can remain infective for months to years. Guidelines governing irrigation water quality and strategies to reduce the risk of disease transmission by foodborne pathogens in irrigation are discussed.
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Affiliation(s)
- Marina Steele
- University of Guelph, Guelph, Ontario, Canada N1H 8J7
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Legnani PP, Leoni E. Effect of processing and storage conditions on the microbiological quality of minimally processed vegetables. Int J Food Sci Technol 2004. [DOI: 10.1111/j.1365-2621.2004.00891.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Yoon Y, Stopforth JD, Kendall PA, Sofos JN. Inactivation of Salmonella during drying and storage of Roma tomatoes exposed to predrying treatments including peeling, blanching, and dipping in organic acid solutions. J Food Prot 2004; 67:1344-52. [PMID: 15270484 DOI: 10.4315/0362-028x-67.7.1344] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The objective of this study was to evaluate the influence of predrying treatments, i.e., peeling, blanching prior to inoculation, and dipping in organic acid solutions, on inactivation of Salmonella during drying (60 degrees C for 14 h) and aerobic storage (25 degrees C for 28 days) of inoculated (five-strain composite, 7.1 to 7.4 log CFU/g) Roma tomato halves. Four predrying treatments groups were established. One group received no treatment (C). In the other three groups, unpeeled-unblanched, unpeeled-blanched (steam blanched at 88 degrees C for 3 min), peeled-unblanched, and peeled-blanched tomato halves were immersed for 10 min in water (W), ascorbic acid solution (AA; 3.40%, pH 2.48), or citric acid solution (CA; 0.21%, pH 2.51). Appropriate dilutions of homogenized tomato samples were spread plated on tryptic soy agar with 0.1% pyruvate and XLT4 agar for bacterial enumeration during drying and storage. Ten minutes of immersion in W, AA, or CA reduced bacterial populations by 0.7 to 1.6 log CFU/g. After 14 h of dehydration, total log reductions in the populations of bacteria were 3.2 to 4.5 (C), 3.7 to 4.9 (W), > 5.6 to > 6.1 (AA), and 4.5 to 5.5 (CA) log CFU/g, depending on type of agar used and condition of tomato samples. During drying and storage, the order of pathogen inactivation for predrying dipping treatments was AA > CA > W > C, with AA and CA rendering bacterial populations below detectable levels ( < 1.3 log CFU/g) prior to storage and between 7 and 14 days of storage, respectively. The results also indicated that peeling and blanching of tomatoes prior to inoculation may not necessarily affect destruction of Salmonella during the drying process. Use of predrying acid dipping treatments of tomatoes, especially in AA, may improve destruction of Salmonella during the dehydration process.
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Affiliation(s)
- Yohan Yoon
- Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523-1171, USA
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Iturriaga MH, Escartín EF, Beuchat LR, Martínez-Peniche R. Effect of inoculum size, relative humidity, storage temperature, and ripening stage on the attachment of Salmonella Montevideo to tomatoes and tomatillos. J Food Prot 2003; 66:1756-61. [PMID: 14572209 DOI: 10.4315/0362-028x-66.10.1756] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The influence of inoculum populations and environmental factors on attachment of Salmonella Montevideo to the surface of tomatoes and tomatillos was evaluated. To study the effect of inoculum size, red, ripe tomatoes were spot-inoculated with bacterial suspensions (10(5) and 10(8) CFU/fruit) and stored at 22 degrees C under 100% relative humidity. The effects of temperature (12, 22, and 30 degrees C) and relative humidity (75, 85, and 97%) on attachment of the pathogen (10(7) CFU/fruit) to tomatoes (red and green) and ripe tomatillos were also evaluated. Inoculated fruits were stored for 90 min at all combinations of temperature and relative humidity, and after rinsing with water, the number of cells attached to the surface was determined. Salmonella Montevideo attached to the surface of tomatoes within 90 min. A direct correlation between the number of attached cells and the population in the inoculum was observed. The percentage of cells that attached immediately after inoculation was approximately 0.3% for the three test products. After storage for 90 min at various temperature and relative humidity conditions, the number of adhering cells ranged from 4.0 to 5.4 log CFU/fruit (1.2% of inoculum). Both the type of product and the temperature/relative humidity combination had a significant (P < 0.05) effect on attachment of Salmonella Montevideo to the surfaces of tomatoes and tomatillos. Scanning electron micrographs of the cuticles of inoculated washed tomatoes and tomatillos revealed typical skin cell patterns, and only a few randomly dispersed Salmonella Montevideo were observed. Deposition of Salmonella Montevideo on the surface of tomatoes and tomatillos could result in attachment and subsequent colonization under suitable conditions.
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Affiliation(s)
- Montserrat H Iturriaga
- Departamento de Investigación y Posgrado en Alimentos, Facultad de Química, Universidad Autónoma de Querétaro, Apartado Postal 796, Querétaro, Querétaro, México
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Singh N, Singh R, Bhunia A. Sequential disinfection of Escherichia coli O157:H7 inoculated alfalfa seeds before and during sprouting using aqueous chlorine dioxide, ozonated water, and thyme essential oil. Lebensm Wiss Technol 2003. [DOI: 10.1016/s0023-6438(02)00224-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Fett WF, Cooke PH. Scanning electron microscopy of native biofilms on mung bean sprouts. Can J Microbiol 2003; 49:45-50. [PMID: 12674347 DOI: 10.1139/w03-002] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Native biofilms present on the adaxial surface of cotyledons of mung bean sprouts (Vigna radiata) were studied by use of scanning electron microscopy. Biofilms were abundant on the cotyledon surfaces and were comprised of rod-shaped bacteria, cocci-shaped bacteria, or yeasts, often with one type of microbe predominant. In contrast to our earlier study of biofilms on green sprouts (alfalfa, clover, broccoli, and sunflower), yeast and cocci were abundant on mung bean. Filamentous fungi were not observed. Sheet-like or fibrillar material (presumably composed of secreted microbial polysaccharides, proteins, lipids, and nucleic acids) fully or partially covered the biofilms. Biofilms up to 5 mm in length were observed, and some biofilms were comprised of more than just a monolayer of microbial cells. Native biofilms on sprout surfaces undoubtedly play an important role in the ecology of plant epiphytic microbes and may also afford protected sites for plant and human bacterial pathogens.
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Affiliation(s)
- William F Fett
- Food Safety Intervention Technologies Research Unit, Eastern Regional Research Center, Agricultural Research Service, USDA, Wyndmoor, PA 19038, USA.
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Harris L, Farber J, Beuchat L, Parish M, Suslow T, Garrett E, Busta F. Outbreaks Associated with Fresh Produce: Incidence, Growth, and Survival of Pathogens in Fresh and Fresh-Cut Produce. Compr Rev Food Sci Food Saf 2003. [DOI: 10.1111/j.1541-4337.2003.tb00031.x] [Citation(s) in RCA: 358] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bornemann R, Zerr DM, Heath J, Koehler J, Grandjean M, Pallipamu R, Duchin J. An outbreak of Salmonella serotype Saintpaul in a children's hospital. Infect Control Hosp Epidemiol 2002; 23:671-6. [PMID: 12452295 DOI: 10.1086/501992] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES To describe a nosocomial outbreak of Salmonella serotype Saintpaul gastroenteritis and to explore risk factors for infection. DESIGN Case-control study. SETTING A 208-bed, university-affiliated children's hospital. PARTICIPANTS Patients hospitalized at Children's Hospital and Regional Medical Center, Seattle, Washington, during February 2001 who had stool specimens obtained for culture at least 24 hours after admission. Case-patients (n = 11) were patients with an indistinguishable strain of Salmonella Saintpaul cultured from their stool. Control-patients (n = 41) were patients hospitalized for problems other than gastroenteritis whose stool cultures were negative for Salmonella. METHODS Risk factors were evaluated using the chi-square test or Fisher's exact test. Continuous variables were compared using the Mann-Whitney U test. A multivariable analysis was performed using logistic regression. The predictor of interest was the receipt of enteral feeding formula mixed by the hospital. RESULTS Case-patients were more likely than control-patients to have received formula mixed by the hospital (OR, 4.2; 95% confidence interval, 1.04 to 17.16). Other variables evaluated were not significant predictors of Salmonella Saintpaul infection. CONCLUSIONS Formula mixed by the hospital appears to have been the source of this Salmonella outbreak. Strict sanitation measures must be ensured in formula preparation and delivery, and bacterial pathogens should be included in the differential diagnosis for nosocomial gastroenteritis.
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Affiliation(s)
- Rena Bornemann
- Children's Hospital and Regional Medical Center, Seattle, WA 98105, USA
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Barak JD, Whitehand LC, Charkowski AO. Differences in attachment of Salmonella enterica serovars and Escherichia coli O157:H7 to alfalfa sprouts. Appl Environ Microbiol 2002; 68:4758-63. [PMID: 12324317 PMCID: PMC126431 DOI: 10.1128/aem.68.10.4758-4763.2002] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2002] [Accepted: 07/04/2002] [Indexed: 11/20/2022] Open
Abstract
Numerous Salmonella enterica and Escherichia coli O157:H7 outbreaks have been associated with contaminated sprouts. We examined how S. enterica serovars, E. coli serotypes, and nonpathogenic bacteria isolated from alfalfa sprouts grow on and adhere to alfalfa sprouts. Growth on and adherence to sprouts were not significantly different among different serovars of S. enterica, but all S. enterica serovars grew on and adhered to alfalfa sprouts significantly better than E. coli O157:H7. E. coli O157:H7 was essentially rinsed from alfalfa sprouts with repeated washing steps, while 1 to 2 log CFU of S. enterica remained attached per sprout. S. enterica Newport adhered to 3-day-old sprouts as well as Pantoea agglomerans and 10-fold more than Pseudomonas putida and Rahnella aquatilis, whereas the growth rates of all four strains throughout seed sprouting were similar. S. enterica Newport and plant-associated bacteria adhered 10- to 1,000-fold more than E. coli O157:H7; however, three of four other E. coli serotypes, isolated from cabbage roots exposed to sewage water following a spill, adhered to sprouts better than E. coli O157:H7 and as well as the Pseudomonas and Rahnella strains. Therefore, attachment to alfalfa sprouts among E. coli serotypes is variable, and nonpathogenic strains of E. coli to be used as surrogates for the study of pathogenic E. coli may be difficult to identify and should be selected carefully, with knowledge of the biology being examined.
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Affiliation(s)
- J D Barak
- Produce Safety and Microbiological Research, Western Regional Research Center, USDA Agricultural Research Service, Albany, California 94710, USA.
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