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Accelerating the Detection of Bacteria in Food Using Artificial Intelligence and Optical Imaging. Appl Environ Microbiol 2023; 89:e0182822. [PMID: 36533914 PMCID: PMC9888199 DOI: 10.1128/aem.01828-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In assessing food microbial safety, the presence of Escherichia coli is a critical indicator of fecal contamination. However, conventional detection methods require the isolation of bacterial macrocolonies for biochemical or genetic characterization, which takes a few days and is labor-intensive. In this study, we show that the real-time object detection and classification algorithm You Only Look Once version 4 (YOLOv4) can accurately identify the presence of E. coli at the microcolony stage after a 3-h cultivation. Integrating with phase-contrast microscopic imaging, YOLOv4 discriminated E. coli from seven other common foodborne bacterial species with an average precision of 94%. This approach also enabled the rapid quantification of E. coli concentrations over 3 orders of magnitude with an R2 of 0.995. For romaine lettuce spiked with E. coli (10 to 103 CFU/g), the trained YOLOv4 detector had a false-negative rate of less than 10%. This approach accelerates analysis and avoids manual result determination, which has the potential to be applied as a rapid and user-friendly bacterial sensing approach in food industries. IMPORTANCE A simple, cost-effective, and rapid method is desired to identify potential pathogen contamination in food products and thus prevent foodborne illnesses and outbreaks. This study combined artificial intelligence (AI) and optical imaging to detect bacteria at the microcolony stage within 3 h of inoculation. This approach eliminates the need for time-consuming culture-based colony isolation and resource-intensive molecular approaches for bacterial identification. The approach developed in this study is broadly applicable for the identification of diverse bacterial species. In addition, this approach can be implemented in resource-limited areas, as it does not require expensive instruments and significantly trained human resources. This AI-assisted detection not only achieves high accuracy in bacterial classification but also provides the potential for automated bacterial detection, reducing labor workloads in food industries, environmental monitoring, and clinical settings.
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Jung D, Rubin JE. Identification of antimicrobial resistant bacteria from plant-based food products imported into Canada. Int J Food Microbiol 2020; 319:108509. [PMID: 31945714 DOI: 10.1016/j.ijfoodmicro.2020.108509] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 12/22/2019] [Accepted: 01/06/2020] [Indexed: 02/08/2023]
Abstract
The role of plant-based foods in the epidemiology of antimicrobial resistance has been inadequately studied. In this investigation, resistant organisms from vegetables, fruits and spices imported into Canada were identified and characterized. A total of 143 products imported from primarily Asian and African countries were purchased from international markets in Saskatoon, Saskatchewan. Samples were selectively cultured for bacterial species where resistance is known to be emerging. The proportions of samples positive for each organism were as follows: E. coli (n = 13, 9.1%), Salmonella spp. (n = 2, 1.4%), ESBL producing Enterobacter spp. (n = 2, 1.4%) and K. pneumoniae (n = 2, 1.4%), S. aureus (n = 7, 4.9%) and Enterococcus spp. (n = 66, 46.2%). Antimicrobial minimum inhibitory concentrations were determined by broth micro-dilution and agar-dilution. Based on the susceptibility of each organism, isolates were screened for resistance genes (β-lactamases and plasmid mediated quinolones resistance determinants) by PCR. Extended-spectrum β-lactamase producing Enterobacteriaceae and methicillin resistant S. aureus (MRSA) were identified from 6/143 (4.2%) and 2/143 (1.4%) of samples respectively. The qnrB, qnrS and aac(6')-Ib-cr plasmid mediated quinolone resistance determinants were identified in 2/143 (1.4%) of samples tested. None of the Enterobacteriaceae isolates were resistant to meropenem or colistin. Similarly, all Enterococcus isolates remained susceptible to ampicillin, penicillin and vancomycin. Finding multi-drug resistant bacteria which are frequently isolated from human infections is concerning, although the contribution of the global food trade to the dissemination of resistance remains cryptic. These results suggest that imported plant-based foods may be an underappreciated source of clinically relevant resistant organisms. Further study is required to address these gaps in our understanding of the epidemiology of resistance, and the magnitude of the risk posed to human health by these organisms.
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Affiliation(s)
- Dongyun Jung
- Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Joseph E Rubin
- Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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de Oliveira Elias S, Noronha TB, Tondo EC. Salmonella spp. and Escherichia coli O157:H7 prevalence and levels on lettuce: A systematic review and meta-analysis. Food Microbiol 2019; 84:103217. [PMID: 31421760 DOI: 10.1016/j.fm.2019.05.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 04/17/2019] [Accepted: 05/01/2019] [Indexed: 11/15/2022]
Abstract
Lettuce (Lactuca sativa), one of the most consumed leafy vegetables in the world, is frequently implicated with foodborne disease (FBD) outbreaks, with Salmonella spp. and Escherichia coli O157:H7 being the most common bacteria to cause this illness. Estimates of prevalence and levels of these pathogens on lettuce are scarce in developed or in developing countries, which hinders risk assessment attempts. In here, we present a systematic review and meta-analysis of reported prevalence and levels of Salmonella spp. and E. coli O157:H7 on lettuce using the worldwide available data. Literature was reviewed and examined the results for inclusion of articles in the meta-analysis. Data (prevalence and/or concentration of Salmonella spp. and E. coli O157:H7 on lettuce, sample characteristic, country of origin, and Salmonella identified serovars) were extracted, and meta-analysis was performed using Open Meta-Analyst, Task Order # 2 software. Although only one work reported the presence of E coli O157:H7 on lettuce, several reports indicated the presence of other, distinct enterohemorrhagic E. coli (EHEC) strains, with a mean prevalence of 0.041 (95% CI: 0.005-0.078) and concentration varying from <3.0 MPN/g to >1100 MPN/g. Furthermore, the mean prevalence of Salmonella spp. on lettuce was 0.041 (95% CI: 0.030-0.052), with reported concentrations varying between 0.054 ± 0.058 CFU/g to 218.78 MPN/g. In addition, subgroup analysis of the presence of Salmonella spp. in lettuce revealed a mean prevalence of the bacteria of 0.028 (95% CI: 0.014-0.042) in developed nations and 0.064 (0.041-0.087) in developing nations, with reports varying from 0.001 in Japan to 0.5 in Burkina Faso. Despite a relatively low prevalence, consumption of lettuce is inherently risky because it usually is eaten raw, without thermal treatment to inactivate pathogens. This potential risk further supports performance of quantitative risk assessments to quantify the probability of FBD caused by Salmonella spp. and E. coli O157:H7 transmitted to lettuce.
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Affiliation(s)
- Susana de Oliveira Elias
- Departamento de Ciências dos Alimentos - Universidade Federal do Rio Grande do Sul, Instituto de Ciência e Tecnologia de Alimentos, Av. Bento Gonçalves, 9500 Prédio 43212 Agronomia, CEP: 91505-970, Porto Alegre, RS, Brazil.
| | - Tiago Baptista Noronha
- Departamento de Ensino, Pesquisa e Extensão - Instituto Federal de Educação, Ciência e Tecnologia Sul-rio-grandense, Rua General Balbão, 81, CEP 96745-000, Charqueadas, RS, Brazil.
| | - Eduardo Cesar Tondo
- Departamento de Ciências dos Alimentos - Universidade Federal do Rio Grande do Sul, Instituto de Ciência e Tecnologia de Alimentos, Av. Bento Gonçalves, 9500 Prédio 43212 Agronomia, CEP: 91505-970, Porto Alegre, RS, Brazil.
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Anturaniemi J, Barrouin-Melo SM, Zaldivar-López S, Sinkko H, Hielm-Björkman A. Owners' perception of acquiring infections through raw pet food: a comprehensive internet-based survey. Vet Rec 2019; 185:658. [PMID: 31427409 PMCID: PMC6952838 DOI: 10.1136/vr.105122] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 06/19/2019] [Accepted: 07/11/2019] [Indexed: 11/26/2022]
Abstract
There has been concerns related to the risk of bacterial contamination from raw pet food to humans, but research is still scarce. The purpose of this cross-sectional study was to use a worldwide internet survey-based data to evaluate the impact of raw pet foods on human health from the owners' experience. From 16 475 households, 0.2 per cent (n=39) reported having had a transmission of pathogen from the raw pet food to a human family member during the time that raw feeding had been used in the household. Only in three of those households the same pathogen that was found in the human sample was analysed and confirmed also in the raw pet food (0.02 per cent of all data). Moreover, 0.1 per cent (n=24) reported suspecting that a disease could have been transmitted to a human from the pet food. Feeding salmon and turkey, using more than 50 per cent of the diet as raw foods and preparing the raw food in the same place and utensils as the family foods all had negative association with infections. Having 2 to 6 year-old children living in the household was associated with more infections, although adults were the most frequently infected.
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Affiliation(s)
- Johanna Anturaniemi
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
| | | | - Sara Zaldivar-López
- Genomics and Animal Breeding Group, Department of Genetics, University of Córdoba, Córdoba, Spain
| | - Hanna Sinkko
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
| | - Anna Hielm-Björkman
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
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Al-Kuraieef AN, Alshawi AH, Alsuhaibani AMA. Effect of the combined action of potassium sorbate and irradiation on the quality-maintenance of strawberries. JOURNAL OF FOOD SCIENCE AND TECHNOLOGY 2019; 56:3374-3379. [PMID: 31274905 PMCID: PMC6582126 DOI: 10.1007/s13197-019-03821-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 05/06/2019] [Accepted: 05/08/2019] [Indexed: 10/26/2022]
Abstract
A relatively short storage life is considered a major problem for the transportation of strawberries across long distances to markets and for exportation. The aim of this research is to study the combined effects of potassium sorbate and radiation (3 kGy) on the microbial load, shelf life and most of the biochemical constituents such as vitamin C and total soluble solids of strawberries. A potassium sorbate (1%) treatment was combined, in practical application, with irradiation (3 kGy) to extend the shelf life of strawberries. All strawberry samples were stored at 4 ± 1 °C (90-92% RH). Quality assessment of the microbial and biochemical constituents, vitamin C, and TSS during the storage period was performed. The results showed that Gamma irradiation alone at 3 kGy extended the shelf life of strawberries to 21 days. Further extension of the shelf life to 21 days was obtained when irradiation (3 kGy) was combined with potassium sorbate treatment. All treatments caused non-significant decreases in vitamin C content during storage, except for the treatment of strawberries with a solution of potassium sorbate, which caused a significant decrease in the vitamin C content, and a gradual decrease in the vitamin C content occurred with an increase in storage time for all treatments.
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Affiliation(s)
- Amal N. Al-Kuraieef
- Department of Nutrition and Food Science, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Amal H. Alshawi
- Department of Nutrition and Food Science, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Amnah M. A. Alsuhaibani
- Department of Nutrition and Food Science, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
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Gao X, Liu Y, Chang Q, Zhang Z, Guo X, Yi X. Microbiological survey of field-grown and retail lettuce in Beijing. J Food Saf 2018. [DOI: 10.1111/jfs.12479] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xiuzhi Gao
- Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Agricultural Product Detection and Control of Spoilage Organisms and Pesticide Residue, Beijing Engineering Laboratory of Probiotics Key Technology Development, Faculty of Food Science and Engineering; Beijing University of Agriculture; Beijing China
| | - Yiqian Liu
- Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Agricultural Product Detection and Control of Spoilage Organisms and Pesticide Residue, Beijing Engineering Laboratory of Probiotics Key Technology Development, Faculty of Food Science and Engineering; Beijing University of Agriculture; Beijing China
| | - Qing Chang
- Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Agricultural Product Detection and Control of Spoilage Organisms and Pesticide Residue, Beijing Engineering Laboratory of Probiotics Key Technology Development, Faculty of Food Science and Engineering; Beijing University of Agriculture; Beijing China
| | - Zihao Zhang
- Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Agricultural Product Detection and Control of Spoilage Organisms and Pesticide Residue, Beijing Engineering Laboratory of Probiotics Key Technology Development, Faculty of Food Science and Engineering; Beijing University of Agriculture; Beijing China
| | - Xu Guo
- Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Agricultural Product Detection and Control of Spoilage Organisms and Pesticide Residue, Beijing Engineering Laboratory of Probiotics Key Technology Development, Faculty of Food Science and Engineering; Beijing University of Agriculture; Beijing China
| | - Xinxin Yi
- Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Agricultural Product Detection and Control of Spoilage Organisms and Pesticide Residue, Beijing Engineering Laboratory of Probiotics Key Technology Development, Faculty of Food Science and Engineering; Beijing University of Agriculture; Beijing China
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Erickson MC, Liao JY, Webb CC, Habteselassie MY, Cannon JL. Inactivation of Escherichia coli O157:H7 and Salmonella deposited on gloves in a liquid state and subjected to drying conditions. Int J Food Microbiol 2018; 266:200-206. [PMID: 29232632 DOI: 10.1016/j.ijfoodmicro.2017.11.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/04/2017] [Accepted: 11/23/2017] [Indexed: 11/16/2022]
Abstract
Gloves are worn by workers harvesting ready-to-eat produce as a deterrent for contaminating the produce with enteric pathogens that may reside on their hands. As fields are not sterile environments, the probability for gloves to become contaminated still exists and therefore it is critical to understand the conditions that affect the survival of pathogens on gloves. Both Escherichia coli O157:H7 and Salmonella deposited on glove surfaces in a liquid state survived longer when the pathogen had been suspended in lettuce sap than when suspended in water. Despite this protection, pathogens deposited on clean single-use gloves were more likely to survive during drying than pathogens deposited on dirty gloves (a film of lettuce sap had been applied to the surface prior to pathogen application and soil had been ground into the gloves). Survival of both E. coli O157:H7 and Salmonella was biphasic with the greatest losses occurring during the first hour of drying followed by much slower losses in the ensuing hours. Pathogens grown in rich media (tryptic soy broth) versus minimal media (M9) as well as those cultured on solid agar versus liquid broth were also more likely to be resistant to desiccation when deposited onto gloves. Although survival of E. coli O157:H7 on nitrile gloves was in general greater than it was on latex gloves, the relative survival of Salmonella on the two glove types was inconsistent. Due to these inconsistencies, no one glove type is considered better than another in reducing the risk for contamination with enteric pathogens. In addition, the extended survival of what are generally referred to as stress-resistant pathogens suggests that gloves either be changed frequently during the day or washed in a disinfectant to reduce the risk of glove contamination that could otherwise contaminate product handled with the contaminated gloves.
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Affiliation(s)
- Marilyn C Erickson
- Center for Food Safety, Department of Food Science and Technology, University of Georgia, 1109 Experiment St., Griffin, GA 30223-1797, USA.
| | - Jye-Yin Liao
- Center for Food Safety, Department of Food Science and Technology, University of Georgia, 1109 Experiment St., Griffin, GA 30223-1797, USA
| | - Cathy C Webb
- Cape Securities, 1600 Pennsylvania Avenue, McDonough, GA 30253, USA
| | - Mussie Y Habteselassie
- Department of Crop and Soil Sciences, University of Georgia, 1109 Experiment St., Griffin, GA 30223-1797, USA
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Evaluation of Bacteriological Profile of the Fresh Produce in Beheira Governorate, Egypt. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2017. [DOI: 10.22207/jpam.11.4.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Young I, Thaivalappil A, Reimer D, Greig J. Food Safety at Farmers' Markets: A Knowledge Synthesis of Published Research. J Food Prot 2017; 80:2033-2047. [PMID: 29148876 DOI: 10.4315/0362-028x.jfp-17-193] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Farmers' markets are increasingly popular venues in North America for the sale of fresh produce and other foods. However, the nature of their operation can present possible food safety issues, challenges, and risks to consumers. A knowledge synthesis was conducted to identify, characterize, and summarize published research on the microbial food safety issues and implications associated with farmers' markets. A scoping review was conducted using the following steps: comprehensive search strategy, relevance screening of abstracts, and characterization of relevant articles. Two subsets of data were prioritized for more detailed systematic review (data extraction and risk-of-bias assessment) and meta-analysis: (i) studies comparing the microbial safety of foods from farmers' markets versus other sources and (ii) studies evaluating the use of food safety practices at farmers' markets. Overall, 83 relevant studies were identified. The majority of studies were published as journal articles (64%), used a cross-sectional design (81%), and were conducted in the United States (78%). Most studies (39%; n = 32) investigated stakeholder, mostly consumer (n = 22), attitudes toward food safety at farmers' markets. Limited but heterogeneous evidence indicated a higher prevalence of Campylobacter and Salmonella in chicken meat from farmers' markets versus other retail sources, but there was no difference in the microbial contamination of fresh produce. Studies evaluating the use of food safety practices at farmers' markets identified some gaps; for example, the average prevalence of vendor hand washing was 4% (95% confidence interval: 0 to 11%; I2 = 27%; n = 5 studies). Twelve foodborne outbreaks and case reports were identified, resulting in a total of 411 illnesses, 38 hospitalizations, and two deaths from 1994 to 2016. Only five intervention studies were identified. Key knowledge gaps and areas warranting future research, training, and education are highlighted and discussed.
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Affiliation(s)
- Ian Young
- 1 School of Occupational and Public Health, Ryerson University, 350 Victoria Street, POD 249, Toronto, Ontario, Canada M5B 2K3; and
| | - Abhinand Thaivalappil
- 1 School of Occupational and Public Health, Ryerson University, 350 Victoria Street, POD 249, Toronto, Ontario, Canada M5B 2K3; and
| | - Danielle Reimer
- 1 School of Occupational and Public Health, Ryerson University, 350 Victoria Street, POD 249, Toronto, Ontario, Canada M5B 2K3; and
| | - Judy Greig
- 2 National Microbiology Laboratory, Public Health Agency of Canada, 160 Research Lane, Suite 206, Guelph, Ontario, Canada N1G 5B2
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Castro-Ibáñez I, Gil MI, Allende A. Ready-to-eat vegetables: Current problems and potential solutions to reduce microbial risk in the production chain. Lebensm Wiss Technol 2017. [DOI: 10.1016/j.lwt.2016.11.073] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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11
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Microbiology of organic and conventionally grown fresh produce. Braz J Microbiol 2016; 47 Suppl 1:99-105. [PMID: 27825766 PMCID: PMC5156503 DOI: 10.1016/j.bjm.2016.10.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 10/05/2016] [Indexed: 11/23/2022] Open
Abstract
Fresh produce is a generalized term for a group of farm-produced crops, including fruits and vegetables. Organic agriculture has been on the rise and attracting the attention of the food production sector, since it uses eco-agricultural principles that are ostensibly environmentally-friendly and provides products potentially free from the residues of agrochemicals. Organic farming practices such as the use of animal manure can however increase the risk of contamination by enteric pathogenic microorganisms and may consequently pose health risks. A number of scientific studies conducted in different countries have compared the microbiological quality of produce samples from organic and conventional production and results are contradictory. While some have reported greater microbial counts in fresh produce from organic production, other studies do not. This manuscript provides a brief review of the current knowledge and summarizes data on the occurrence of pathogenic microorganisms in vegetables from organic production.
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Reddy SP, Wang H, Adams JK, Feng PCH. Prevalence and Characteristics of Salmonella Serotypes Isolated from Fresh Produce Marketed in the United States. J Food Prot 2016; 79:6-16. [PMID: 26735024 DOI: 10.4315/0362-028x.jfp-15-274] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Salmonella continues to rank as one of the most costly foodborne pathogens, and more illnesses are now associated with the consumption of fresh produce. The U.S. Department of Agriculture Microbiological Data Program (MDP) sampled select commodities of fresh fruit and vegetables and tested them for Salmonella, pathogenic Escherichia coli, and Listeria. The Salmonella strains isolated were further characterized by serotype, antimicrobial resistance, and pulsed-field gel electrophoresis profile. This article summarizes the Salmonella data collected by the MDP between 2002 and 2012. The results show that the rates of Salmonella prevalence ranged from absent to 0.34% in cilantro. A total of 152 isolates consisting of over 50 different serotypes were isolated from the various produce types, and the top five were Salmonella enterica serotype Cubana, S. enterica subspecies arizonae (subsp. IIIa) and diarizonae (subsp. IIIb), and S. enterica serotypes Newport, Javiana, and Infantis. Among these, Salmonella serotypes Newport and Javiana are also listed among the top five Salmonella serotypes that caused most foodborne outbreaks. Other serotypes that are frequent causes of infection, such as S. enterica serotypes Typhimurium and Enteritidis, were also found in fresh produce but were not prevalent. About 25% of the MDP samples were imported produce, including 65% of green onions, 44% of tomatoes, 42% of hot peppers, and 41% of cantaloupes. However, imported produce did not show higher numbers of Salmonella-positive samples, and in some products, like cilantro, all of the Salmonella isolates were from domestic samples. About 6.5% of the Salmonella isolates were resistant to the antimicrobial compounds tested, but no single commodity or serotype was found to be the most common carrier of resistant strains or of resistance. The pulsed-field gel electrophoresis profiles of the produce isolates showed similarities with Salmonella isolates from meat samples and from outbreaks, but there were also profile diversities among the strains within some serotypes, like Salmonella Newport.
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Affiliation(s)
- Shanker P Reddy
- Agricultural Marketing Service, U.S. Department of Agriculture, Washington, D.C. 20250, USA
| | - Hua Wang
- Division of Microbiology, U.S. Food and Drug Administration, College Park, Maryland 20740, USA
| | - Jennifer K Adams
- Association of Public Health Laboratories, Silver Spring, Maryland 20910, USA
| | - Peter C H Feng
- Division of Microbiology, U.S. Food and Drug Administration, College Park, Maryland 20740, USA.
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Levy DJ, Beck NK, Kossik AL, Patti T, Meschke JS, Calicchia M, Hellberg RS. Microbial safety and quality of fresh herbs from Los Angeles, Orange County and Seattle farmers' markets. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2015; 95:2641-2645. [PMID: 25382560 DOI: 10.1002/jsfa.6996] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/31/2014] [Accepted: 11/04/2014] [Indexed: 06/04/2023]
Abstract
BACKGROUND Farmers' markets have been growing in popularity in the United States, but the microbial quality and safety of the food sold at these markets is currently unknown. The purpose of this study was to assess the microbial safety and quality of fresh basil, parsley and cilantro sold at farmers' markets in the Los Angeles, Orange County and greater Seattle areas. RESULTS A total of 133 samples (52 basil, 41 cilantro and 40 parsley) were collected from 13 different farmers' markets and tested for Salmonella and generic Escherichia coli. One sample (parsley) was confirmed positive for Salmonella and 24.1% of samples were positive for generic E. coli, with a range of 0.70-3.15 log CFU g(-1) . Among the herbs tested, basil showed the highest percentage of samples with generic E. coli (26.9%), followed by cilantro (24.4%) and then parsley (20.0%). For 12% of samples, the levels of generic E. coli exceeded guidelines established by the Public Health Laboratory Service for microbiological quality of ready-to-eat foods. CONCLUSION Overall, this study indicates the presence of Salmonella and generic E. coli in fresh herbs sold at farmers' markets; however, additional studies are needed to determine the sources and extent of contamination.
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Affiliation(s)
- Donna J Levy
- Food Science and Nutrition, Schmid College of Science and Technology, Chapman University, One University Drive, Orange, CA 92866, USA
| | - Nicola K Beck
- School of Public Health, University of Washington, Seattle, WA, USA
| | | | - Taylor Patti
- Food Science and Nutrition, Schmid College of Science and Technology, Chapman University, One University Drive, Orange, CA 92866, USA
| | - J Scott Meschke
- School of Public Health, University of Washington, Seattle, WA, USA
| | - Melissa Calicchia
- Food Safety Solutions and Food Microbiological Laboratories, 10653 Progress Way, Cypress, CA 90630, USA
| | - Rosalee S Hellberg
- Food Science and Nutrition, Schmid College of Science and Technology, Chapman University, One University Drive, Orange, CA 92866, USA
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Microbiological analysis of pre-packed sweet basil (Ocimum basilicum) and coriander (Coriandrum sativum) leaves for the presence of Salmonella spp. and Shiga toxin-producing E. coli. Int J Food Microbiol 2015; 208:11-8. [DOI: 10.1016/j.ijfoodmicro.2015.05.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 02/03/2015] [Accepted: 05/16/2015] [Indexed: 11/21/2022]
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Pan F, Li X, Carabez J, Ragosta G, Fernandez KL, Wang E, Thiptara A, Antaki E, Atwill ER. Cross-sectional survey of indicator and pathogenic bacteria on vegetables sold from Asian vendors at farmers' markets in northern California. J Food Prot 2015; 78:602-8. [PMID: 25719888 DOI: 10.4315/0362-028x.jfp-14-095] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A cross-sectional survey was conducted during summer 2013 to determine the occurrence of Escherichia coli, fecal coliforms (FCs), E. coli O157:H7, and Salmonella on raw vegetable commodities common to Asian cuisine from 21 vendors or farmers at six farmers' markets in northern California. Based on 242 samples from six commodities (basil, yardlong beans, bitter squash, okra, squash stems and leaves, cilantro), 100% of samples had detectable FCs and 20% had detectable E. coli. The mean concentrations were 0.67 log CFU/g and 1.26 log CFU per bundle for E. coli and 4.00 log CFU/g and 6.26 log CFU per bundle for FCs. Vegetables irrigated with ground versus surface water contained lower concentrations of FCs, but this difference was not observed for E. coli. Yardlong beans, bitter squash, and okra had lower levels of FCs compared with basil, cilantro, and squash stems and leaves. Sixteen (6.6%) samples had detectable levels of Salmonella serovars (Newport, Enteritidis, Agona, and Worthington), with the majority of positives found in cilantro and squash stems and leaves. There was a twofold higher probability of Salmonella contamination in samples from growers or vendors who stated that they used organic farming practices compared with samples from those using conventional farming practices. Lastly, the concentrations of FC and E. coli bacteria were significantly associated with Salmonella contamination: for each additional 100 CFU/g or bundle, the probability of Salmonella contamination increased by ∼15 and ∼30%, respectively. None of the samples had detectable E. coli O157:H7.
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Affiliation(s)
- Fengguang Pan
- Department of Food Science and Engineering, Jilin University, 5333 Xi'an Road, Changchun 130062, People's Republic of China
| | - Xunde Li
- Western Institute for Food Safety and Security, 1477 Drew Avenue, Suite 101, Davis, California 95616, USA.
| | - Jennifer Carabez
- Department of Population Health and Reproduction, 1089 Veterinary Medicine Drive, Davis, California 95616, USA
| | - Guy Ragosta
- Department of Population Health and Reproduction, 1089 Veterinary Medicine Drive, Davis, California 95616, USA
| | - Kristine L Fernandez
- Department of Population Health and Reproduction, 1089 Veterinary Medicine Drive, Davis, California 95616, USA
| | - Elaine Wang
- Department of Population Health and Reproduction, 1089 Veterinary Medicine Drive, Davis, California 95616, USA
| | - Anyarat Thiptara
- Department of Population Health and Reproduction, 1089 Veterinary Medicine Drive, Davis, California 95616, USA
| | - Elizabeth Antaki
- Department of Population Health and Reproduction, 1089 Veterinary Medicine Drive, Davis, California 95616, USA
| | - Edward R Atwill
- Department of Food Science and Engineering, Jilin University, 5333 Xi'an Road, Changchun 130062, People's Republic of China; Western Institute for Food Safety and Security, 1477 Drew Avenue, Suite 101, Davis, California 95616, USA; Department of Population Health and Reproduction, 1089 Veterinary Medicine Drive, Davis, California 95616, USA.
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16
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Bovo F, De Cesare A, Manfreda G, Bach S, Delaquis P. Fate of Salmonella enterica in a mixed ingredient salad containing lettuce, cheddar cheese, and cooked chicken meat. J Food Prot 2015; 78:491-7. [PMID: 25719871 DOI: 10.4315/0362-028x.jfp-14-187] [Citation(s) in RCA: 9] [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
Food service and retail sectors offer consumers a variety of mixed ingredient salads that contain fresh-cut vegetables and other ingredients such as fruits, nuts, cereals, dairy products, cooked seafood, cooked meat, cured meats, or dairy products obtained from external suppliers. Little is known about the behavior of enteric bacterial pathogens in mixed ingredient salads. A model system was developed to examine the fate of Salmonella enterica (inoculum consisting of S. enterica serovars Agona, Typhimurium, Enteritidis, Brandenberg, and Kentucky) on the surface of romaine lettuce tissues incubated alone and in direct contact with Cheddar cheese or cooked chicken. S. enterica survived but did not grow on lettuce tissues incubated alone or in contact with Cheddar cheese for 6 days at either 6 or 14°C. In contrast, populations increased from 2.01 ± 0.22 to 9.26 ± 0.22 CFU/cm(2) when lettuce washed in water was incubated in contact with cooked chicken at 14°C. Populations on lettuce leaves were reduced to 1.28 ± 0.14 CFU/cm(2) by washing with a chlorine solution (70 ppm of free chlorine) but increased to 8.45 ± 0.22 CFU/cm(2) after 6 days at 14°C. Experimentation with a commercial product in which one third of the fresh-cut romaine lettuce was replaced with inoculated lettuce revealed that S. enterica populations increased by 4 log CFU/g during storage for 3 days at 14°C. These findings indicate that rapid growth of bacterial enteric pathogens may occur in mixed ingredient salads; therefore, strict temperature control during the manufacture, distribution, handling, and storage of these products is critical.
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Affiliation(s)
- Federica Bovo
- Department of Agricultural and Food Sciences, University of Bologna, Via del Florio 2, 40064 Ozzano dell'Emilia (BO), Italy
| | - Alessandra De Cesare
- Department of Agricultural and Food Sciences, University of Bologna, Via del Florio 2, 40064 Ozzano dell'Emilia (BO), Italy
| | - Gerardo Manfreda
- Department of Agricultural and Food Sciences, University of Bologna, Via del Florio 2, 40064 Ozzano dell'Emilia (BO), Italy
| | - Susan Bach
- Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, 4200 Highway 97 South, Summerland, British Columbia, Canada V0H 1Z0
| | - Pascal Delaquis
- Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, 4200 Highway 97 South, Summerland, British Columbia, Canada V0H 1Z0.
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17
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Wood JL, Chen JC, Friesen E, Delaquis P, Allen KJ. Microbiological survey of locally grown lettuce sold at farmers' markets in Vancouver, British Columbia. J Food Prot 2015; 78:203-8. [PMID: 25581197 DOI: 10.4315/0362-028x.jfp-14-199] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Increased consumer demand for fresh leafy produce has been paralleled by an increase in outbreaks and illness associated with these foods. Presently, data on the microbiological quality and safety of produce harvested in the Lower Mainland of British Columbia is lacking. Therefore, fresh green, red, and romaine lettuce samples (n = 68) were obtained from five regional farmers' markets in late summer of 2012 and subsequently analyzed to determine total numbers of aerobic bacteria, coliforms, and Escherichia coli. Additionally, enrichment procedures were used to detect low concentrations of E. coli. Obtained E. coli isolates were subjected to multiplex PCRs to determine phylogenetic groupings and the presence of virulence genes (eaeA, hlyA, stx1, and stx2). All E. coli were tested for resistance to 15 antibiotics using a disk diffusion assay. Lettuce samples yielded mean aerobic colony counts of 6.3 log CFU/g. Coliforms were detected in 72% of samples, with a median concentration of 1.9 log CFU/g. Of samples, 13% were found to harbor E. coli, with a median level of 0.7 log CFU/g. Antibiogram typing of all E. coli (n = 33) revealed that 97% possessed resistance to one or more antimicrobials, with resistance to amikacin (58%), trimethoprim (48%), and trimethoprim-sulfamethoxazole (45%) being the most common. Phylogroup typing showed that 79% of these isolates belonged to group B1, with the remaining assigned to groups A (9%) or D (12%); no virulence genes were detected. Considering that phylogroup indicators suggestive of fecal contamination (groups A and D E. coli) were recovered in lettuce samples presented at retail, further work is required to explore at what point along the food chain contamination occurs. Also, this study shows the presence of multidrug-resistant E. coli in fresh vegetables. Summed, these data provide important information on the microbiological quality of leafy vegetables grown in British Columbia through the detection and characterization of frequently used indicator organisms.
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Affiliation(s)
- Jayde L Wood
- Food, Nutrition and Health Program, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Jessica C Chen
- Food, Nutrition and Health Program, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Elsie Friesen
- Ministry of Agriculture, Food Safety and Inspection Branch, Agrifood Safety and Quality, Abbotsford, British Columbia, Canada V2S 8A3
| | - Pascal Delaquis
- Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, Summerland, British Columbia, Canada V0H 1Z0
| | - Kevin J Allen
- Food, Nutrition and Health Program, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4.
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18
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Scientific Opinion on the risk posed by pathogens in food of non‐animal origin. Part 2 (Salmonella, Yersinia, Shigella and Norovirus in bulb and stem vegetables, and carrots). EFSA J 2014. [DOI: 10.2903/j.efsa.2014.3937] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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19
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Scientific Opinion on the risk posed by pathogens in food of non-animal origin. Part 2 (Salmonellain melons). EFSA J 2014. [DOI: 10.2903/j.efsa.2014.3831] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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20
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Scientific Opinion on the risk posed by pathogens in food of non-animal origin. Part 2 (Salmonellaand Norovirus in tomatoes). EFSA J 2014. [DOI: 10.2903/j.efsa.2014.3832] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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21
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Marvasi M, George AS, Giurcanu MC, Hochmuth GJ, Noel JT, Teplitski M. Effect of the irrigation regime on the susceptibility of pepper and tomato to post-harvest proliferation of Salmonella enterica. Food Microbiol 2014; 46:139-144. [PMID: 25475277 DOI: 10.1016/j.fm.2014.07.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 07/15/2014] [Accepted: 07/17/2014] [Indexed: 11/18/2022]
Abstract
Raw produce is increasingly recognized as a vehicle of human gastroenteritis. Non-typhoidal Salmonella, pathogenic Escherichia coli, and other human pathogens have been isolated from fruits and vegetables in the field and in the marketplace, which led to the hypothesis that these microbes can use plants as alternate hosts. However, environmental and physiological factors that facilitate persistence of these bacteria in the crop production environment and make produce more vulnerable to post-harvest contamination have not been fully delineated. This study tested the effect of irrigation regimes on the susceptibility of peppers and tomatoes to post-harvest proliferation of Salmonella. The experiments were carried out over three experimental seasons in two locations using seven strains of Salmonella. The irrigation regime per se did not affect susceptibility of tomatoes and peppers to post-harvest proliferation of Salmonella; however, in some of the seasons, irrigation regime-dependent differences were observed. Red peppers and tomatoes were more conducive to proliferation of Salmonella than green fruit in all seasons. Inter-seasonal differences were the strongest factors affecting proliferation of Salmonella in peppers.
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Affiliation(s)
- Massimiliano Marvasi
- Department of Soil and Water Science, University of Florida, Gainesville, FL, USA
| | - Andrée S George
- Department of Soil and Water Science, University of Florida, Gainesville, FL, USA
| | - Mihai C Giurcanu
- Department of Statistics, University of Florida, Gainesville, FL, USA
| | - George J Hochmuth
- Department of Soil and Water Science, University of Florida, Gainesville, FL, USA
| | - Jason T Noel
- Department of Soil and Water Science, University of Florida, Gainesville, FL, USA
| | - Max Teplitski
- Department of Soil and Water Science, University of Florida, Gainesville, FL, USA.
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22
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Holvoet K, De Keuckelaere A, Sampers I, Van Haute S, Stals A, Uyttendaele M. Quantitative study of cross-contamination with Escherichia coli, E. coli O157, MS2 phage and murine norovirus in a simulated fresh-cut lettuce wash process. Food Control 2014. [DOI: 10.1016/j.foodcont.2013.09.051] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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23
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Scientific Opinion on the risk posed by pathogens in food of non‐animal origin. Part 2 (Salmonella and Norovirus in leafy greens eaten raw as salads). EFSA J 2014. [DOI: 10.2903/j.efsa.2014.3600] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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24
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Jensen AN, Storm C, Forslund A, Baggesen DL, Dalsgaard A. Escherichia coli contamination of lettuce grown in soils amended with animal slurry. J Food Prot 2013; 76:1137-44. [PMID: 23834787 DOI: 10.4315/0362-028x.jfp-13-011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A pilot study was conducted to assess the transfer of Escherichia coli from animal slurry fertilizer to lettuce, with E. coli serving as an indicator of fecal contamination and as an indicator for potential bacterial enteric pathogens. Animal slurry was applied as fertilizer to three Danish agricultural fields prior to the planting of lettuce seedlings. At harvest, leaves (25 g) of 10 lettuce heads were pooled into one sample unit (n = 147). Soil samples (100 g) were collected from one field before slurry application and four times during the growth period (n = 75). E. coli was enumerated in slurry, soil, and lettuce on 3M Petrifilm Select E. coli Count Plates containing 16 mg/liter streptomycin, 16 mg/liter ampicillin, or no antimicrobial agent. Selected E. coli isolates (n = 83) originating from the slurry, soil, and lettuce were genotyped by pulsed-field gel electrophoresis (PFGE) to determine the similarity of isolates. The slurry applied to the fields contained 3.0 to 4.5 log CFU/g E. coli. E. coli was found in 36 to 54% of the lettuce samples, streptomycin-resistant E. coli was found in 10.0 to 18.0% of the lettuce samples, and ampicillin-resistant E. coli in 0 to 2.0% of the lettuce samples (the detection limit was 1 log CFU/g). The concentration of E. coli exceeded 2 log CFU/g in 19.0% of the lettuce samples. No E. coli was detected in the soil before the slurry was applied, but after, E. coli was present until the last sampling day (harvest), when 10 of 15 soil samples contained E. coli. A relatively higher frequency of E. coli in lettuce compared with the soil samples at harvest suggests environmental sources of fecal contamination, e.g., wildlife. The higher frequency was supported by the finding of 21 different PFGE types among the E. coli isolates, with only a few common PFGE types between slurry, soil, and lettuce. The frequent finding of fecal-contaminated lettuce indicates that human pathogens such as Salmonella and Campylobacter can be present and represent food safety hazards.
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Affiliation(s)
- A N Jensen
- Division of Food Microbiology, National Food Institute, Technical University of Denmark, Bülowsvej 27, 1790 Copenhagen V, Denmark.
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25
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Scientific Opinion on VTEC‐seropathotype and scientific criteria regarding pathogenicity assessment. EFSA J 2013. [DOI: 10.2903/j.efsa.2013.3138] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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26
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Allen KJ, Kovacevic J, Cancarevic A, Wood J, Xu J, Gill B, Allen JK, Mesak LR. Microbiological survey of imported produce available at retail across Canada. Int J Food Microbiol 2013; 162:135-42. [PMID: 23416548 DOI: 10.1016/j.ijfoodmicro.2013.01.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 01/04/2013] [Accepted: 01/15/2013] [Indexed: 12/18/2022]
Abstract
Increasing consumption and year-round consumer demand for fresh, minimally processed green vegetables have been observed in Canada and other developed countries. However, in the past two decades, produce has been increasingly implicated in outbreaks and correspondingly recognized as a vector for the transmission of pathogenic microorganisms. To this end, we examined the microbiological quality of imported produce available at retail across Canada during a period of limited domestic availability. In total, 106 samples obtained from five Canadian cities were purchased from retail outlets and subjected to microbiological analyses, including aerobic plate (APC) and coliform counts, and enrichments for enterococci, indicator Escherichia coli, E. coli O157:H7 and Salmonella spp. Also, recovered Enterococcus faecalis and Enterococcus faecium were screened for antimicrobial resistance (AMR). Overall, samples included herbs (n=61), leafy greens (n=25), and spinach (n=20) deriving from five countries (Columbia, Dominican Republic, Guatemala, Mexico, and the United States [US]). APCs were consistent across commodities regardless of country, ranging from mean log10 CFU/g of 6.1 to 7.4, with no significant differences observed. Excluding a single leafy green sample from Guatemala, the lowest prevalence of coliforms was for Mexican herbs (22.2%), with a high of 66.7% on US leafy greens. With the exception of spinach, concentrations of coliforms varied widely, ranging from undetectable to too numerous to count (>8.5 log10 CFU/g). Of the commodities assessed, Mexican and US spinach had the lowest coliform concentrations (undetectable to 4.0 log10 CFU/g). Organic herbs and conventional leafy greens possessed significantly lower (p<0.05) prevalence of coliforms compared to conventional herbs and organic leafy greens, respectively. The most frequent recovery of indicator E. coli was observed for herbs, with 11.1, 8.3, and 3.7% prevalence observed in samples from Columbia, US, and Mexico, respectively. For spinach, 0 and 6.7% of Mexican and US samples tested positive, while no leafy green samples from either country were positive. No E. coli O157:H7 or Salmonella spp. were detected. E. faecium and E. faecalis were recovered from 15.1 and 5.7% of samples, respectively. Although no glycopeptide resistance was observed, resistance to other clinically relevant antibiotics was noteworthy in both species. Overall, though microbiological quality indicators were frequently high, E. coli O157:H7 and Salmonella were not detected. However, the presence of resistance and reduced susceptibility to clinically relevant antimicrobials in recovered enterococci demonstrate imported fresh produce may serve as a vehicle for the transmission of antimicrobial resistance across national borders.
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Affiliation(s)
- Kevin J Allen
- Food, Nutrition and Health Program, Faculty of Land and Food Systems, The University of British Columbia, 2205 East Mall, Vancouver, British Columbia, Canada V6T 1Z4.
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27
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28
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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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29
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Lewis Ivey ML, LeJeune JT, Miller SA. Vegetable producers’ perceptions of food safety hazards in the Midwestern USA. Food Control 2012. [DOI: 10.1016/j.foodcont.2012.01.065] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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30
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Kim SR, Yoon Y, Kim WI, Park KH, Yun HJ, Chung DH, Yun JC, Ryu KY. Comparison of sample preparation methods for the recovery of foodborne pathogens from fresh produce. J Food Prot 2012; 75:1213-8. [PMID: 22980003 DOI: 10.4315/0362-028x.jfp-11-420] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Sample preparation methods (pummeling, pulsifying, sonication, and shaking by hand) were compared for achieving maximum recovery of foodborne pathogens from iceberg lettuce, perilla leaves, cucumber, green pepper, and cherry tomato. Antimicrobial and dehydration effects also were examined to investigate causes of poor recovery of pathogens. Each produce type was inoculated with Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Bacillus cereus at 6.0 log CFU/cm(2), and samples were prepared using the four methods. Bacterial populations recovered from the five types of produce were significantly different (P < 0.05) according to sample preparation methods and produce type. The bacterial populations recovered from pummeled and pulsified samples were higher (P < 0.05) than those recovered from sonicated and hand-shaken samples, except for cherry tomato. The number of bacteria recovered from produce was reduced (P < 0.05) from that of the inoculum by 0.16 to 2.69 log CFU/cm(2). Although extracts of iceberg lettuce, perilla leaves, cucumber, and green pepper had no antimicrobial activity, the populations of E. coli O157:H7, Salmonella Typhimurium, B. cereus, and L. monocytogenes in cherry tomato extract were slightly reduced after these treatments (P < 0.05). The pathogen populations on perilla leaves and cherry tomatoes decreased by >2 log CFU/cm(2) after exposure to 40% relative humidity for 1 h. No reduction was observed when the five pathogens were exposed to 90% relative humidity. These data suggest that pummeling and pulsifying are optimal sample preparation methods for detection of microorganisms. Acidic produce such as cherry tomato should be treated with a method that does not cause sample breakdown so that acid stress on the bacteria can be minimized. Dehydration stress also affects recovery of pathogens from produce.
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Affiliation(s)
- Se-Ri Kim
- Microbial Safety Division, Department of Agri-Food Safety, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, South Korea
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31
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32
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Santos M, Cavaco A, Gouveia J, Novais M, Nogueira P, Pedroso L, Ferreira M. Evaluation of minimally processed salads commercialized in Portugal. Food Control 2012. [DOI: 10.1016/j.foodcont.2011.06.022] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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33
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Pathogen-produce pair attribution risk ranking tool to prioritize fresh produce commodity and pathogen combinations for further evaluation (P3ARRT). Food Control 2011. [DOI: 10.1016/j.foodcont.2011.04.028] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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34
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Koseki S, Mizuno Y, Kawasaki S, Yamamoto K. A survey of iceberg lettuce for the presence of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in Japan. J Food Prot 2011; 74:1543-6. [PMID: 21902925 DOI: 10.4315/0362-028x.jfp-10-424] [Citation(s) in RCA: 23] [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
No information has been available on the prevalence of pathogens in fresh produce in Japan. In the present study, information was collected on the occurrence of contamination by Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in iceberg lettuce in a Japanese retail store. A total of 419 samples of lettuce that had been harvested in different districts and/or by different producers from July 2008 to March 2009 were examined. A multiplex PCR method was used to simultaneously identify the three bacterial pathogens. No pathogenic bacteria, including Salmonella, E. coli O157:H7, and L. monocytogenes, were detected from any of the samples with this highly sensitive and validated procedure. The aerobic bacteria plate counts and coliform bacteria counts in lettuce throughout the examination period did not show any seasonal trends, and the numbers were comparable to those reported by others from around the world. Based on the results of this study, we concluded that none of the three major pathogens were present in this limited survey of iceberg lettuce sold by a retailer in Japan.
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Affiliation(s)
- Shigenobu Koseki
- National Food Research Institute, 2-1-12, Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
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35
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Molecular identification and antibiotic susceptibility patterns of Escherichia coli isolates from sheep faeces samples. ACTA ACUST UNITED AC 2010. [DOI: 10.1007/s00580-010-1134-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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36
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Hsu WY, Simonne A, Jitareerat P, Marshall MR. Low-dose irradiation improves microbial quality and shelf life of fresh mint (Mentha piperita L.) without compromising visual quality. J Food Sci 2010; 75:M222-30. [PMID: 20546414 DOI: 10.1111/j.1750-3841.2010.01568.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
UNLABELLED The effects of low-dose irradiation (0.25 to 2 kGy) and postirradiation storage (at 4 degrees C) on microbial and visual quality, color values (L*, a*, b*, chroma, and hue [ degrees ]), and chlorophyll content (Chl a, Chl b, and total Chl) of fresh mint were evaluated. Samples inoculated with E. coli O157:H7, Salmonella, and MS2 bacteriophage were irradiated and evaluated. E. coli O157:H7 and Salmonella populations were reduced by 2 to 2.4, 3.5, and 5.8 log CFU/g, respectively, 1 d after treatment with 0.25, 0.60, and 1 kGy, respectively, and were completely eliminated at 2 kGy. None of the irradiation doses (P < 0.0001) reduced MS2 bacteriophage populations by more than 0.60 log PFU/g. Irradiation doses did not affect visual quality and samples remained of excellent to good quality (score 7.75 to 9) for up to 9 d of storage. Irradiation at 0.60, 1, and 2 kGy increased (P < 0.0001) Chl a, Chl b, and total Chl. Both total Chl and Chl a decreased significantly after 3 d of storage. Significant decreases in Chl b were not observed until day 12 of storage. Color values (L*, b*, and chroma) were not significantly different until day 6 of storage and hue ( degrees ) remained unchanged (179 degrees ) for the entire storage period of 12 d. Overall, irradiation did not change L*, a*, b*, or chroma. These results demonstrate that irradiation of fresh mint at 2 kGy has the potential to improve its microbial quality and extend its shelf life without compromising its visual quality and color. PRACTICAL APPLICATION Mints and other raw fresh herbs are widely used for flavoring as well as garnish in a variety of dishes without further cooking. However, mint is one considered as one of the high-risk herbs when it comes to microbial contamination. We have evaluated the use of gamma irradiation treatment at very low doses ranging from 0 to 2 kGy to eliminate seeded Salmonella spp, E. coli O157:H7, and MS2 bacteriophage, a surrogate of hepatitis A virus. We found that low-dose irradiation (1.0 to 2.0 kGy) appears to be a promising method for improving the microbiological quality of fresh mint without compromising its visual and color attributes. This method may be applied to many popular fresh culinary herbs that are commonly used as garnishes in Asian cuisine.
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Affiliation(s)
- Wei-Yea Hsu
- Dept. of Family, Youth and Community Sciences, Univ. of Florida, Gainesville, FL 32611-0310, USA
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37
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Erickson MC. Microbial Risks Associated with Cabbage, Carrots, Celery, Onions, and Deli Salads Made with These Produce Items. Compr Rev Food Sci Food Saf 2010; 9:602-619. [DOI: 10.1111/j.1541-4337.2010.00129.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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38
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Bohaychuk VM, Bradbury RW, Dimock R, Fehr M, Gensler GE, King RK, Rieve R, Romero Barrios P. A microbiological survey of selected Alberta-grown fresh produce from farmers' markets in Alberta, Canada. J Food Prot 2009; 72:415-20. [PMID: 19350990 DOI: 10.4315/0362-028x-72.2.415] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Previously there was no available information on the levels of indicator bacteria and the prevalence of pathogens in fresh produce grown in Alberta, Canada. Baseline information on the occurrence and levels of Escherichia coli and the prevalence of foodborne pathogens in selected produce items available to consumers from farmers' and public markets in two large urban centers and surrounding areas in Alberta was obtained. A total of 10 large markets with between 1 and 12 produce vendors and 26 small markets with between 1 and 6 produce vendors were sampled from 21 June to 7 October 2007. Lettuce (128 samples), spinach (59 samples), tomatoes (120 samples), carrots (206 samples), green onions (129 samples), and strawberries (31 samples) were analyzed for E. coli, Salmonella, E. coli O157:H7, and Campylobacter spp. Lettuce, spinach, green onion, and strawberry samples were also tested for the presence of Cryptosporidium spp. Information on whether produce was grown using organic or conventional practices was obtained from the produce vendors. E. coli was isolated from 8.2% of the samples that included lettuce, spinach, carrots, and green onions. The bacterial counts ranged from <0.48 to >3.04 Log most probable number per g. E. coli was not isolated from tomatoes or strawberries. The percentage of positive samples ranged from 4.4% for carrots to 27.1% for spinach. Salmonella, E. coli O157:H7, and Campylobacter spp. were not isolated from any of the samples. Cryptosporidium was identified by PCR in one sample of spinach (0.6% of the samples).
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Affiliation(s)
- V M Bohaychuk
- Food Safety Division, Alberta Agriculture and Rural Development, 6909-116 Street, Edmonton, Alberta, Canada.
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Recent advances in the microbial safety of fresh fruits and vegetables. ADVANCES IN FOOD AND NUTRITION RESEARCH 2009; 57:155-208. [PMID: 19595387 DOI: 10.1016/s1043-4526(09)57004-0] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Foodborne illness outbreaks linked to fresh produce are becoming more frequent and widespread. High impact outbreaks, such as that associated with spinach contaminated with Escherichia coli O157:H7, resulted in almost 200 cases of foodborne illness across North America and >$300 m market losses. Over the last decade there has been intensive research into gaining an understanding on the interactions of human pathogens with plants and how microbiological safety of fresh produce can be improved. The following review will provide an update on the food safety issues linked to fresh produce. An overview of recent foodborne illness outbreaks linked to fresh produce. The types of human pathogens encountered will be described and how they can be transferred from their normal animal or human host to fresh produce. The interaction of human pathogens with growing plants will be discussed, in addition to novel intervention methods to enhance the microbiological safety of fresh produce.
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Arthur TM, Brichta-Harhay DM, Bosilevac JM, Guerini MN, Kalchayanand N, Wells JE, Shackelford SD, Wheeler TL, Koohmaraie M. Prevalence and characterization of Salmonella in bovine lymph nodes potentially destined for use in ground beef. J Food Prot 2008; 71:1685-8. [PMID: 18724765 DOI: 10.4315/0362-028x-71.8.1685] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A potential source of pathogenic bacteria in ground beef is the lymphatic system, specifically the lymph nodes. Bacteria have been isolated from the lymph nodes of cattle at slaughter; however, most studies have dealt with mesenteric lymph nodes, which are not normally incorporated into ground beef. The objective of the current study was to determine the prevalence and multidrug-resistance status of Salmonella in bovine lymph nodes associated with lean and fat trimmings that might be utilized in ground beef production. Bovine lymph nodes (n = 1,140) were collected from commercial beef processing plants. Half of the lymph nodes sampled were obtained from cull cow and bull processing plants, and the remainder were obtained from fed beef processing plants. Lymph nodes located in chuck and flank adipose tissue were collected for this study. Salmonella prevalence in the lymph node samples was low, with an overall prevalence of 1.6% and a 95% confidence interval of 0.85 to 2.3%. Lymph nodes from cull cattle carcasses had a higher prevalence of Salmonella than did those from fed cattle carcasses. Lymph nodes from the flanks of cow and bull carcasses had the highest prevalence at 3.86%, whereas lymph nodes from the chuck region of fed cattle carcasses had the lowest prevalence at 0.35%. Three of the 18 Salmonella-positive lymph node samples contained multidrug-resistant Salmonella, and all 3 samples were from cull cattle.
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Affiliation(s)
- Terrance M Arthur
- U.S. Department of Agriculture, Agricultural Research Service, Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, Nebraska 68933-0166, USA.
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Cuesta Alonso EP, Gilliland SE, Krehbiel CR. Incidence and toxin production ability of Escherichia coli O157:H7 isolated from cattle trucks. J Food Prot 2007; 70:2383-5. [PMID: 17969622 DOI: 10.4315/0362-028x-70.10.2383] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Twelve cattle trucks were analyzed for the presence of Escherichia coli O157:H7. Three of them had been washed prior to arrival, and the others had not. Seventy-five percent of the trailers were positive for the presence of this foodborne pathogen. A total of 54 cultures were isolated and identified as E. coli O157:H7, all from the trucks that had not been cleaned. Most of the cultures (96.4%) produced Shiga-like toxin (verotoxin). No E. coli O157:H7 was detected in cattle trucks that were cleaned before arrival at the cattle pens. The incidence of E. coli O157:H7 in transport trailers increases the potential risk of contamination of cattle and transmission from farms to feedlots and to packing plants. This contamination increases the potential of contamination of meat during harvest and the risk of foodborne illnesses.
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Affiliation(s)
- E P Cuesta Alonso
- Department of Animal Science, Food and Agricultural Products Center, Oklahoma State University, Stillwater, Oklahoma 74078-6055, USA
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