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Liu S, Xue R, Qin W, Yang X, Ye Q, Wu Q. Performance and transcriptome analysis of Salmonella enterica serovar Enteritidis PT 30 under persistent desiccation stress: Cultured by lawn and broth methods. Food Microbiol 2023; 115:104323. [PMID: 37567618 DOI: 10.1016/j.fm.2023.104323] [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: 02/13/2023] [Revised: 06/04/2023] [Accepted: 06/13/2023] [Indexed: 08/13/2023]
Abstract
Lawn-harvest method uses a solid medium (e.g., tryptic soy agar, TSA) to produce bacterial lawns and is widely accepted for the culture of microorganisms in microbial studies of low-moisture foods (LMFs, foods with water activity less than 0.85). It produces desiccation-tolerant cells with higher D-values in LMFs; however, little is known about the molecular mechanisms underlying bacterial resistance. Salmonella enterica Enteritidis PT 30 (S. Enteritidis), the most pertinent pathogen in LMFs, was cultured in TSA and tryptic soy broth (TSB). Cells were harvested and inoculated on filter papers to assess their performance under a relative humidity of 32 ± 2%. Transcriptome analysis of cultured cells during long-term desiccation (24, 72, and 168 h) was conducted in TruSeq PE Cluster Kit (Illumina) by paired-end methods. Lawn-cultured S. Enteritidis cells have stronger survivability (only decreased by 0.78 ± 0.12 log after 130 d of storage) and heat tolerance (higher D/β value) than those from the broth method. More desiccation genes of lawn-cultured cells were significantly upregulated from growth to long-term desiccation. Differentially expressed genes were the most enriched in the ribosome and sulfur metabolism pathways in the lawn- and broth-cultured groups. This study tracked the transcriptomic differences between two cultured groups in response to long-term desiccation stress and revealed some molecular mechanisms underlying their different suitability in microbial studies of LMFs.
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Affiliation(s)
- Shuxiang Liu
- College of Food Science, Sichuan Agricultural University, Ya'an, 625014, China; Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070, China.
| | - Ruimin Xue
- College of Food Science, Sichuan Agricultural University, Ya'an, 625014, China
| | - Wen Qin
- College of Food Science, Sichuan Agricultural University, Ya'an, 625014, China
| | - Xiaojuan Yang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070, China
| | - Qinghua Ye
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070, China
| | - Qingping Wu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070, China.
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2
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Mkangara M. Prevention and Control of Human Salmonella enterica Infections: An Implication in Food Safety. INTERNATIONAL JOURNAL OF FOOD SCIENCE 2023; 2023:8899596. [PMID: 37727836 PMCID: PMC10506869 DOI: 10.1155/2023/8899596] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 08/19/2023] [Accepted: 08/26/2023] [Indexed: 09/21/2023]
Abstract
Salmonella is a foodborne zoonotic pathogen causing diarrhoeal disease to humans after consuming contaminated water, animal, and plant products. The bacterium is the third leading cause of human death among diarrhoeal diseases worldwide. Therefore, human salmonellosis is of public health concern demanding integrated interventions against the causative agent, Salmonella enterica. The prevention of salmonellosis in humans is intricate due to several factors, including an immune-stable individual infected with S. enterica continuing to shed live bacteria without showing any clinical signs. Similarly, the asymptomatic Salmonella animals are the source of salmonellosis in humans after consuming contaminated food products. Furthermore, the contaminated products of plant and animal origin are a menace in food industries due to Salmonella biofilms, which enhance colonization, persistence, and survival of bacteria on equipment. The contaminated food products resulting from bacteria on equipment offset the economic competition of food industries and partner institutions in international business. The most worldwide prevalent broad-range Salmonella serovars affecting humans are Salmonella Typhimurium and Salmonella Enteritidis, and poultry products, among others, are the primary source of infection. The broader range of Salmonella serovars creates concern over multiple strategies for preventing and controlling Salmonella contamination in foods to enhance food safety for humans. Among the strategies for preventing and controlling Salmonella spread in animal and plant products include biosecurity measures, isolation and quarantine, epidemiological surveillance, farming systems, herbs and spices, and vaccination. Other measures are the application of phages, probiotics, prebiotics, and nanoparticles reduced and capped with antimicrobial agents. Therefore, Salmonella-free products, such as beef, pork, poultry meat, eggs, milk, and plant foods, such as vegetables and fruits, will prevent humans from Salmonella infection. This review explains Salmonella infection in humans caused by consuming contaminated foods and the interventions against Salmonella contamination in foods to enhance food safety and quality for humans.
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Affiliation(s)
- Mwanaisha Mkangara
- Department of Science and Laboratory Technology, Dar es Salaam Institute of Technology, P.O. Box 2958, Dar es Salaam, Tanzania
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3
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Fay ML, Salazar JK, Ren Y, Wu Z, Mate M, Khouja BA, Lingareddygari P, Liggans G. Growth Kinetics of Listeria monocytogenes and Salmonella enterica on Dehydrated Vegetables during Rehydration and Subsequent Storage. Foods 2023; 12:2561. [PMID: 37444299 DOI: 10.3390/foods12132561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/20/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
Dehydrated vegetables have low water activities and do not support the proliferation of pathogenic bacteria. Once rehydrated, vegetables can be incorporated into other foods or held for later use. The aim of this study was to examine the survival and proliferation of Listeria monocytogenes and Salmonella enterica on dehydrated vegetables during rehydration and subsequent storage. Carrots, corn, onion, bell peppers, and potatoes were heat dehydrated, inoculated at 4 log CFU/g, and rehydrated at either 5 or 25 °C for 24 h. Following rehydration, vegetables were stored at 5, 10, or 25 °C for 7 d. Both L. monocytogenes and S. enterica survived on all vegetables under all conditions examined. After 24 h of rehydration at 5 °C, pathogen populations on the vegetables were generally <1.70 log CFU/g, whereas rehydration at 25 °C resulted in populations of 2.28 to 6.25 log CFU/g. The highest growth rates during storage were observed by L. monocytogenes on potatoes and S. enterica on carrots (2.37 ± 0.61 and 1.63 ± 0.18 log CFU/g/d, respectively) at 25 °C when rehydration occurred at 5 °C. Results indicate that pathogen proliferation on the vegetables is both rehydration temperature and matrix dependent and highlight the importance of holding rehydrated vegetables at refrigeration temperatures to hinder pathogen proliferation. Results from this study inform time and temperature controls for the safety of these food products.
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Affiliation(s)
- Megan L Fay
- Division of Food Processing Science and Technology, U. S. Food and Drug Administration, Bedford Park, IL 60501, USA
| | - Joelle K Salazar
- Division of Food Processing Science and Technology, U. S. Food and Drug Administration, Bedford Park, IL 60501, USA
| | - Yuying Ren
- Department of Food Science and Nutrition, Illinois Institute of Technology, Bedford Park, IL 60501, USA
| | - Zihui Wu
- Department of Food Science and Nutrition, Illinois Institute of Technology, Bedford Park, IL 60501, USA
| | - Madhuri Mate
- Department of Food Science and Nutrition, Illinois Institute of Technology, Bedford Park, IL 60501, USA
| | - Bashayer A Khouja
- Division of Food Processing Science and Technology, U. S. Food and Drug Administration, Bedford Park, IL 60501, USA
| | - Pravalika Lingareddygari
- Division of Food Processing Science and Technology, U. S. Food and Drug Administration, Bedford Park, IL 60501, USA
| | - Girvin Liggans
- Office of Food Safety, U. S. Food and Drug Administration, College Park, MD 20740, USA
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4
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Sun S, Xie Y, Yang R, Zhu MJ, Sablani S, Tang J. The influence of temperature and water activity on thermal resistance of Salmonella in milk chocolate. Food Control 2023. [DOI: 10.1016/j.foodcont.2022.109292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Practice and Progress: Updates on Outbreaks, Advances in Research, and Processing Technologies for Low-moisture Food Safety. J Food Prot 2023; 86:100018. [PMID: 36916598 DOI: 10.1016/j.jfp.2022.11.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 11/03/2022] [Accepted: 11/20/2022] [Indexed: 12/31/2022]
Abstract
Large, renowned outbreaks associated with low-moisture foods (LMFs) bring to light some of the potential, inherent risks that accompany foods with long shelf lives if pathogen contamination occurs. Subsequently, in 2013, Beuchat et al. (2013) noted the increased concern regarding these foods, specifically noting examples of persistence and resistance of pathogens in low-water activity foods (LWAFs), prevalence of pathogens in LWAF processing environments, and sources of and preventive measures for contamination of LWAFs. For the last decade, the body of knowledge related to LMF safety has exponentially expanded. This growing field and interest in LMF safety have led researchers to delve into survival and persistence studies, revealing that some foodborne pathogens can survive in LWAFs for months to years. Research has also uncovered many complications of working with foodborne pathogens in desiccated states, such as inoculation methods and molecular mechanisms that can impact pathogen survival and persistence. Moreover, outbreaks, recalls, and developments in LMF safety research have created a cascading feedback loop of pushing the field forward, which has also led to increased attention on how industry can improve LMF safety and raise safety standards. Scientists across academia, government agencies, and industry have partnered to develop and evaluate innovate thermal and nonthermal technologies to use on LMFs, which are described in the presented review. The objective of this review was to describe aspects of the extensive progress made by researchers and industry members in LMF safety, including lessons-learned about outbreaks and recalls, expansion of knowledge base about pathogens that contaminate LMFs, and mitigation strategies currently employed or in development to reduce food safety risks associated with LMFs.
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Recent development in low-moisture foods: Microbial safety and thermal process. Food Res Int 2022; 155:111072. [DOI: 10.1016/j.foodres.2022.111072] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 11/17/2022]
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Morasi RM, Rall VLM, Dantas STA, Alonso VPP, Silva NCC. Salmonella spp. in low water activity food: Occurrence, survival mechanisms, and thermoresistance. J Food Sci 2022; 87:2310-2323. [PMID: 35478321 DOI: 10.1111/1750-3841.16152] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 03/04/2022] [Accepted: 03/22/2022] [Indexed: 01/17/2023]
Abstract
The occurrence of disease outbreaks involving low-water-activity (aw ) foods has gained increased prominence due in part to the fact that reducing free water in these foods is normally a measure that controls the growth and multiplication of pathogenic microorganisms. Salmonella, one of the main bacteria involved in these outbreaks, represents a major public health problem worldwide and in Brazil, which highlights the importance of good manufacturing and handling practices for food quality. The virulence of this pathogen, associated with its high ability to persist in the environment, makes Salmonella one of the main challenges for the food industry. The objectives of this article are to present the general characteristics, virulence, thermoresistance, control, and relevance of Salmonella in foodborne diseases, and describe the so-called low-water-activity foods and the salmonellosis outbreaks involving them.
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Affiliation(s)
- Rafaela Martins Morasi
- Department of Food Sciences And Nutrition, Faculty of Food Engineering, State University of Campinas (UNICAMP), Monteiro Lobato Street, 80, Campinas, São Paulo, Brazil
| | - Vera Lúcia Mores Rall
- Sector of Microbiology and Immunology, Department of Chemical and Biological Sciences, Institute of Biosciences of Botucatu, São Paulo State University (UNESP), Botucatu, Brazil
| | - Stéfani Thais Alves Dantas
- Sector of Microbiology and Immunology, Department of Chemical and Biological Sciences, Institute of Biosciences of Botucatu, São Paulo State University (UNESP), Botucatu, Brazil
| | - Vanessa Pereira Perez Alonso
- Department of Food Sciences And Nutrition, Faculty of Food Engineering, State University of Campinas (UNICAMP), Monteiro Lobato Street, 80, Campinas, São Paulo, Brazil
| | - Nathália Cristina Cirone Silva
- Department of Food Sciences And Nutrition, Faculty of Food Engineering, State University of Campinas (UNICAMP), Monteiro Lobato Street, 80, Campinas, São Paulo, Brazil
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8
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Larkin L, Pardos de la Gandara M, Hoban A, Pulford C, Jourdan-Da Silva N, de Valk H, Browning L, Falkenhorst G, Simon S, Lachmann R, Dryselius R, Karamehmedovic N, Börjesson S, van Cauteren D, Laisnez V, Mattheus W, Pijnacker R, van den Beld M, Mossong J, Ragimbeau C, Vergison A, Thorstensen Brandal L, Lange H, Garvey P, Nielsen CS, Herrera León S, Varela C, Chattaway M, Weill FX, Brown D, McKeown P. Investigation of an international outbreak of multidrug-resistant monophasic Salmonella Typhimurium associated with chocolate products, EU/EEA and United Kingdom, February to April 2022. Euro Surveill 2022; 27. [PMID: 35426359 PMCID: PMC9012091 DOI: 10.2807/1560-7917.es.2022.27.15.2200314] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
An extensive multi-country outbreak of multidrug-resistant monophasic Salmonella Typhimurium infection in 10 countries with 150 reported cases, predominantly affecting young children, has been linked to chocolate products produced by a large multinational company. Extensive withdrawals and recalls of multiple product lines have been undertaken. With Easter approaching, widespread product distribution and the vulnerability of the affected population, early and effective real-time sharing of microbiological and epidemiological information has been of critical importance in effectively managing this serious food-borne incident.
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Affiliation(s)
- Lesley Larkin
- Gastrointestinal Infections and Food Safety (One Health Unit), UK Health Security Agency, London, United Kingdom
| | - Maria Pardos de la Gandara
- Institut Pasteur, Université Paris Cité, Centre National de Référence des E. coli, Shigella et Salmonella, Unité des Bactéries pathogènes entériques, Paris, France
| | - Ann Hoban
- Gastrointestinal Infections and Food Safety (One Health Unit), UK Health Security Agency, London, United Kingdom
| | - Caisey Pulford
- Gastrointestinal Infections and Food Safety (One Health Unit), UK Health Security Agency, London, United Kingdom
| | | | - Henriette de Valk
- Sante Publique France, Direction des Maladies Infectieuses Unité EAZ, Paris, France
| | - Lynda Browning
- Clinical and Protecting Health Directorate, Public Health Scotland, Glasgow, United Kingdom
| | - Gerhard Falkenhorst
- Robert Koch Institute, Department of Infectious Disease Epidemiology FG 35 - Gastrointestinal Infections, Zoonoses and Tropical Infections, Berlin, Germany
| | - Sandra Simon
- Robert Koch Institute, Department of Infectious Diseases, Unit for Enteropathogenic Bacteria and Legionella / National Reference Centre for Salmonella and other Bacterial Enterics, Wernigerode, Germany
| | - Raskit Lachmann
- Robert Koch Institute, Department of Infectious Disease Epidemiology FG 35 - Gastrointestinal Infections, Zoonoses and Tropical Infections, Berlin, Germany
| | - Rikard Dryselius
- Public Health Agency of Sweden, Unit for Zoonoses and Antibiotic Resistance, Stockholm, Sweden
| | - Nadja Karamehmedovic
- Public Health Agency of Sweden, Unit for laboratory surveillance of bacterial pathogens, Stockholm, Sweden
| | - Stefan Börjesson
- Public Health Agency of Sweden, Unit for Zoonoses and Antibiotic Resistance, Stockholm, Sweden
| | - Dieter van Cauteren
- Epidemiology of infectious diseases, Department of Epidemiology and Public Health, Sciensano, Brussels, Belgium
| | - Valeska Laisnez
- ECDC Fellowship Programme, Field Epidemiology path (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
- Epidemiology of infectious diseases, Department of Epidemiology and Public Health, Sciensano, Brussels, Belgium
| | - Wesley Mattheus
- National Reference Centre for Salmonella and Shigella, Sciensano, Brussels, Belgium
| | - Roan Pijnacker
- National Institute for Public Health and the Environment (RIVM), Centre for Infectious Disease Control, Bilthoven, Netherlands
| | - Maaike van den Beld
- National Institute for Public Health and the Environment (RIVM), Centre for Infectious Disease Control, Bilthoven, Netherlands
| | - Joël Mossong
- Health Inspection, Health Directorate, Luxembourg
| | - Catherine Ragimbeau
- Laboratoire National de Santé, Epidemiology and Microbial Genomics, Dudelange, Luxembourg
| | | | - Lin Thorstensen Brandal
- Department of Infection Control and Preparedness, Norwegian Institute of Public Health, Oslo, Norway
| | - Heidi Lange
- Department of Infection Control and Preparedness, Norwegian Institute of Public Health, Oslo, Norway
| | | | - Charlotte Salgaard Nielsen
- ECDC Fellowship Programme, Field Epidemiology path (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
- HSE -Health Protection Surveillance Centre, Dublin, Ireland
| | - Silvia Herrera León
- Instituto de Salud Carlos III. Centro Nacional de Microbiología, Madrid, Spain
| | - Carmen Varela
- Instituto de Salud Carlos III. CIBER epidemiología y salud pública. Madrid, Spain
| | - Marie Chattaway
- Specialist Scientific Reference Service (Salmonella), Gastrointestinal Bacteria Reference Unit, UK Health Security Agency, London, United Kingdom
| | - François-Xavier Weill
- Institut Pasteur, Université Paris Cité, Centre National de Référence des E. coli, Shigella et Salmonella, Unité des Bactéries pathogènes entériques, Paris, France
| | - Derek Brown
- Scottish Microbiology Reference Laboratories, Glasgow, United Kingdom
| | - Paul McKeown
- HSE -Health Protection Surveillance Centre, Dublin, Ireland
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Salazar JK, Tesfaldet B, Zamperlini M, Streufert R, Fay M, Keller SE. Desiccation Survival of Salmonella enterica,Escherichia coli, and Enterococcus faecium Related to Initial Cell Level and Cellular Components. J Food Prot 2022; 85:398-405. [PMID: 34855937 DOI: 10.4315/jfp-21-320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/01/2021] [Indexed: 11/11/2022]
Abstract
ABSTRACT Salmonella enterica is well known for its ability to survive and persist in low-moisture environments. Previous studies have indicated a link between the initial cell level and the population of Salmonella that survives after desiccation and subsequent storage; however, how the initial cell concentration affects survival is unknown. This study was conducted to examine this phenomenon and to determine whether it occurs in other microorganisms, specifically Shiga toxigenic Escherichia coli (STEC) and Enterococcus faecium. Salmonella, STEC, and E. faecium were grown as sessile cells on Trypticase soy agar with yeast extract (TSAYE) and harvested in buffered peptone water (BPW). To determine recovery at different initial cell levels, cultures were diluted to 9, 7, and 5 log CFU/mL and applied to filters. Filters were dried for 24 h and then stored for 28 days at 25°C and 33% relative humidity. During storage, cells were recovered from filters with BPW and cultivated on TSAYE. Recovery of both Salmonella and E. coli, but not E. faecium, was nonproportional. Lower initial populations were less viable after 24 h of desiccation; ≥10 log CFU/mL was recovered when 11 log CFU/mL was desiccated, but <3 log CFU/mL was recovered when 5 log CFU/mL was desiccated. Once dried, persistence did not appear affected by initial cell concentration. When inactivated (heat-treated) cells were added to the diluent, recovery of Salmonella was proportional with respect to the initial cell level. To further examine the response to desiccation, Salmonella was diluted in BPW containing 1 of 11 test cell components related to quorum sensing or known to affect desiccation resistance to assess recovery and persistence. Of the 11 additions, only cell debris fractions, cell-free extract, and peptidoglycan improved recovery of Salmonella. Desiccation survival appears related to cell wall components; however, the exact mechanism affecting survival remains unknown. HIGHLIGHTS
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Affiliation(s)
- Joelle K Salazar
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 6502 South Archer Road, Bedford Park, Illinois 60501; and
| | - Bereket Tesfaldet
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 5001 Campus Drive, College Park, Maryland 20740, USA
| | - Michelle Zamperlini
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 5001 Campus Drive, College Park, Maryland 20740, USA
| | - Rachel Streufert
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 6502 South Archer Road, Bedford Park, Illinois 60501; and
| | - Megan Fay
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 6502 South Archer Road, Bedford Park, Illinois 60501; and
| | - Susanne E Keller
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 6502 South Archer Road, Bedford Park, Illinois 60501; and
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Jiao S, Zhang H, Liao M, Hayouka Z, Jing P. Investigation of the potential direct and cross protection effects of sublethal injured Salmonella Typhimurium induced by radio frequency heating stress. Food Res Int 2021; 150:110789. [PMID: 34865804 DOI: 10.1016/j.foodres.2021.110789] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 09/22/2021] [Accepted: 10/24/2021] [Indexed: 10/20/2022]
Abstract
Many studies demonstrated that radio frequency (RF) was an effective pasteurization method for low-moisture foods (LMFs), and our previous study confirmed RF heating stress generated sublethal injured cells (SICs) of Salmonella enterica serovar Typhimurium (S. Typhimurium) in red pepper powder with initial aw ≥ 0.53. So this study investigated the potential direct protection and cross protection effects of the SICs of S. Typhimurium to multiple stresses, and analyzed fatty acid composition and cell morphology. Results showed that the SICs were repaired after incubating for 5 h, and there were no obvious direct and cross protection effects by exposing to different external stresses (heat, 15% ethanol, pH 3.0 acid buffer solution, 10% salt). According to the fatty acid composition analysis, no significant difference (p > 0.05) between the ratio of unsaturated to saturated fatty acids (UFA/SFA) was observed for SICs of S. Typhimurium and control cells, indicating the same membrane fluidity which can support the experimental results. This study investigated and confirmed there are no direct and cross protection effects for the SICs of S. Typhimurium induced by RF heating stress, and it would be helpful for deeply understand the response of pathogens under RF heating stress.
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Affiliation(s)
- Shunshan Jiao
- SJTU-OSU Innovation Center for Environmental Sustainability and Food Control, Shanghai Food Safety and Engineering Technology Research Center, Key Laboratory of Urban Agriculture, Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China
| | - Hangjin Zhang
- SJTU-OSU Innovation Center for Environmental Sustainability and Food Control, Shanghai Food Safety and Engineering Technology Research Center, Key Laboratory of Urban Agriculture, Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China
| | - Meiji Liao
- SJTU-OSU Innovation Center for Environmental Sustainability and Food Control, Shanghai Food Safety and Engineering Technology Research Center, Key Laboratory of Urban Agriculture, Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China
| | - Zvi Hayouka
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Pu Jing
- SJTU-OSU Innovation Center for Environmental Sustainability and Food Control, Shanghai Food Safety and Engineering Technology Research Center, Key Laboratory of Urban Agriculture, Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China.
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11
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Onarinde BA. Survival of Salmonella Enteritidis Phage Type 30 on Brazil Nut Kernels and Pumpkin Seeds Stored at 8, 23, and 37°C. J Food Prot 2021; 84:2044-2052. [PMID: 34129662 DOI: 10.4315/jfp-20-213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 06/11/2021] [Indexed: 11/11/2022]
Abstract
ABSTRACT Experiments were performed to assess the survival of Salmonella on whole Brazil nut kernels and pumpkin seeds stored at 8, 23, and 37°C. Brazil nut kernels and pumpkin seeds were inoculated with bacterial inoculum containing 10.4 log CFU/mL Salmonella Enteritidis phage type 30 and aseptically dried at room temperature for 24 h. After the drying step, levels of Salmonella recovered from Brazil nut kernels and pumpkin seeds were 8.67 ± 0.01 and 9.27 ± 0.03 log CFU/g, respectively. The survival of Salmonella and change in water activity was assessed over 413 days. Although Salmonella survived throughout the storage period, significant differences were recorded between the storage temperatures. Results showed that the survival of Salmonella Enteritidis phage type 30 was more enhanced at 8°C compared with storage at 23 and 37°C. Comparing the survival of Salmonella on the two products at different storage temperatures, there was no significant difference between the means of Salmonella counts for the two products. Results show that Salmonella survived longer on pumpkin seeds stored at 8°C (P = 0.53, compared with Brazil nut kernels), and at 23 and 37°C, Salmonella survived longer on Brazil nut kernels (P = 0.12, compared with pumpkin seeds). The highest and lowest survival of Salmonella was observed on pumpkin seeds with decay rates of -0.003 ± 0.001 and -0.015 ± 0.001 log CFU/g/day for pumpkin seeds stored at 8 and 37°C, respectively. The water activity values recorded on days 2 and 413 for Brazil nut kernels stored at 8, 23, and 37°C were 0.424 and 0.434, 0.383 and 0.385, and 0.372 and 0.256, respectively. For pumpkin seeds stored at 8, 23, and 37°C, water activity values recorded on days 2 and 413 were 0.754 and 0.412, 0.627 and 0.350, and 0.787 and 0.205, respectively. The data obtained in this study provide useful insight on the influence of temperature on the survival of Salmonella on the surface of Brazil nut kernels and pumpkin seeds. HIGHLIGHTS
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Affiliation(s)
- Bukola A Onarinde
- National Centre for Food Manufacturing, University of Lincoln, Minerva House, Park Road, Holbeach, Spalding PE12 7PT, UK
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13
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Streufert RK, Keller SE, Salazar JK. Relationship of Growth Conditions to Desiccation Tolerance of Salmonella enterica, Escherichia coli, and Listeria monocytogenes. J Food Prot 2021; 84:1380-1384. [PMID: 33852728 DOI: 10.4315/jfp-21-077] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/12/2021] [Indexed: 11/11/2022]
Abstract
ABSTRACT Growth on solid media as sessile cells is believed to increase the desiccation tolerance of Salmonella enterica. However, the reasons behind increased resistance have not been well explored. In addition, the same effect has not been examined for other foodborne pathogens such as pathogenic Escherichia coli or Listeria monocytogenes. The purpose of this research was twofold: first, to determine the role of oxygenation during growth on the desiccation resistance of S. enterica, E. coli, and L. monocytogenes, and second, to determine the effect of sessile versus planktonic growth on the desiccation resistance of these pathogens. Three different serotypes each of Salmonella, E. coli, and L. monocytogenes were cultured in Trypticase soy broth with 0.6% yeast extract (TSBYE), with (aerobic) shaking or on TSBYE with agar under either aerobic or anaerobic conditions and harvested in the stationary phase. After adding cell suspensions to cellulose filter disks, pathogen survival was determined by enumeration before drying (0 h) and after drying for 24 h. Results showed statistical differences in harvested initial populations before drying. For Salmonella, a correlation was found between high initial population and greater survival on desiccation (P = 0.05). In addition, statistical differences (P ≤ 0.05) between survival based on growth type were identified. However, differences found were not the same for the three pathogens, or between their serotypes. In general, Salmonella and E. coli desiccation resistance followed the pattern of aerobic agar media ≥ liquid media ≥ anaerobic agar media. For L. monocytogenes serotypes, resistance to desiccation was not statistically different based on mode of growth. These results indicate growth on solid media under aerobic conditions is not always necessary for optimal desiccation survival, but may be beneficial when the desiccation resistance of the test serotype is unknown. HIGHLIGHTS
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Affiliation(s)
- Rachel K Streufert
- Division of Food Processing Science and Technology, U.S. Food and Drug Administration, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
| | - Susanne E Keller
- Division of Food Processing Science and Technology, U.S. Food and Drug Administration, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
| | - Joelle K Salazar
- Division of Food Processing Science and Technology, U.S. Food and Drug Administration, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
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14
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Yan R, Pinto G, Taylor-Roseman R, Cogan K, D'Alesandre G, Kovac J. Evaluation of the Thermal Inactivation of a Salmonella Serotype Oranienburg Strain During Cocoa Roasting at Conditions Relevant to the Fine Chocolate Industry. Front Microbiol 2021; 12:576337. [PMID: 33763036 PMCID: PMC7982832 DOI: 10.3389/fmicb.2021.576337] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 02/04/2021] [Indexed: 12/31/2022] Open
Abstract
Cocoa roasting produces and enhances distinct flavor of chocolate and acts as a critical control point for inactivation of foodborne pathogens in chocolate production. In this study, the inactivation kinetics of Salmonella enterica subsp. enterica serotype Oranienburg strain was assessed on whole cocoa beans using roasting protocols relevant to the fine chocolate industry. Beans were inoculated with 107-108 log10 CFU/bean of Salmonella Oranienburg and roasted at 100-150°C for 2-100 min. A greater than 5 log10 reduction of S. Oranienburg was experimentally achieved after 10-min roasting at 150°C. Data were fitted using log-linear and Weibull models. The log-linear models indicated that the roasting times (D) needed to achieve a decimal reduction of Salmonella at 100, 110, 115, 120, 130, and 140°C were 33.34, 18.57, 12.92, 10.50, 4.20, and 1.90 min, respectively. A Weibull model indicated a decrease in the Salmonella inactivation rate over time (β < 1). Statistical analysis indicated that the Weibull model fitted the data better compared to a log-linear model. These data demonstrate the efficacy of cocoa roasting in inactivation of Salmonella and may be used to guide food safety decision-making.
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Affiliation(s)
- Runan Yan
- Department of Food Science, The Pennsylvania State University, University Park, PA, United States
| | - Gabriella Pinto
- Department of Food Science, The Pennsylvania State University, University Park, PA, United States
| | | | - Karen Cogan
- Dandelion Chocolate Inc., San Francisco, CA, United States
| | | | - Jasna Kovac
- Department of Food Science, The Pennsylvania State University, University Park, PA, United States
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15
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Igo MJ, Schaffner DW. Models for factors influencing pathogen survival in low water activity foods from literature data are highly significant but show large unexplained variance. Food Microbiol 2021; 98:103783. [PMID: 33875211 DOI: 10.1016/j.fm.2021.103783] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 11/19/2022]
Abstract
Factors that control pathogen survival in low water activity foods are not well understood and vary greatly from food to food. A literature search was performed to locate data on the survival of foodborne pathogens in low-water activity (<0.70) foods held at temperatures <37 °C. Data were extracted from 67 publications and simple linear regression models were fit to each data set to estimate log linear rates of change. Multiple linear stepwise regression models for factors influencing survival rate were developed. Subset regression modeling gave relatively low adjusted R2 values of 0.33, 0.37, and 0.48 for Salmonella, E. coli and L. monocytogenes respectively, but all subset models were highly significant (p < 1.0e-9). Subset regression models showed that Salmonella survival was significantly (p < 0.05) influenced by temperature, serovar and strain type, water activity, inoculum preparation method, and inoculation method. E. coli survival was significantly influenced by temperature, water activity, and inoculum preparation. L. monocytogenes survival was significantly influenced by temperature, serovar and strain type, and inoculum preparation method. While many factors were highly significant (p < 0.001), the high degrees of variability show that there is still much to learn about the factors which govern pathogen survival in low water activity foods.
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Affiliation(s)
- Matthew J Igo
- Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, NJ, 08901, USA
| | - Donald W Schaffner
- Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, NJ, 08901, USA.
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16
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Liu Z, Liao C, Golson K, Phillips S, Wang L. Survival of common foodborne pathogens on dried apricots made with and without sulfur dioxide treatment. Food Control 2021. [DOI: 10.1016/j.foodcont.2020.107569] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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17
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Dhakal J, Aldrich CG. A Comparison of Salmonella Survival and Detection Using an Enrichment Technique in Dry- and Wet-Inoculated Rendered Chicken Fat Treated with Sodium Bisulfate. J Food Prot 2021; 84:249-254. [PMID: 32916702 DOI: 10.4315/jfp-20-183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 09/09/2020] [Indexed: 01/29/2023]
Abstract
ABSTRACT The differences in the recovery of Salmonella from rendered chicken fat treated with sodium bisulfate (SBS) when inoculated with a dry versus wet inoculum were evaluated. Food-grade rendered chicken fat was inoculated with a dry inoculum and a wet inoculum containing a cocktail of Salmonella serovars (Enteritidis, Heidelberg, and Typhimurium). In addition, the effect of an antimicrobial treatment (SBS) against Salmonella in both the aqueous phase and fat phase of the chicken fat was evaluated. The untreated control samples in the aqueous phase had a consistent level of Salmonella (∼7 log) when both the dry and wet inocula were used. In the SBS-treated aqueous phase, Salmonella pathogens were not detectable after 6 h when the wet inoculum was used; when the dry inoculum was used, Salmonella pathogens were not detectable at 24 h. Salmonella pathogens were detected for up to 6 h in the SBS-treated fat phase when the dry inoculum was used compared with 2 h with the wet inoculum. The 24-h fat samples that failed to show growth on Trypticase soy agar were enriched for Salmonella isolation, followed by confirmation by PCR using primers for the invA gene. SBS-treated and control samples from the dry-inoculated rendered chicken fat and the inoculated control from the wet-inoculated rendered chicken fat tested positive for Salmonella. However, the SBS-treated sample from the wet-inoculated fat was negative for Salmonella. The use of dry SBS powder against dry Salmonella inoculum in the fat matrix caused only ∼2.8-log reduction after 24 h compared with ∼2.2-log reduction in the positive control. However, the recovery of Salmonella from untreated control fat was lower and was not different (P > 0.05) from that recovered from the SBS-treated fat. The results suggest that viable but nonculturable states of Salmonella may develop in rendered chicken fat or that injured cells may be present, which indicates that testing should include an enrichment and appropriate molecular confirmation instead of agar plating alone. HIGHLIGHTS
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Affiliation(s)
- Janak Dhakal
- Department of Grain Science and Industry, Kansas State University, Manhattan, Kansas 66506, USA
| | - Charles G Aldrich
- Department of Grain Science and Industry, Kansas State University, Manhattan, Kansas 66506, USA
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18
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JuÁrez Arana CD, MartÍnez Peniche RA, MartÍnez MG, Iturriaga MH. Microbiological Profile, Incidence, and Behavior of Salmonella on Seeds Traded in Mexican Markets. J Food Prot 2021; 84:99-105. [PMID: 32882022 DOI: 10.4315/jfp-19-595] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 08/30/2020] [Indexed: 11/11/2022]
Abstract
ABSTRACT Consumption of seeds has increased in recent years due to their high nutrient content. However, Salmonella outbreaks associated with the consumption of low-water-activity food items have also increased, although these food items do not support microbial growth. The main goal of this study was to quantify microbial indicators and to determine the prevalence and content of Salmonella in chia, amaranth, and sesame seeds obtained from Mexican retail outlets. In addition, the behavior of this pathogen on seeds was evaluated. One hundred samples of each product (chia, amaranth, and sesame seeds) were collected from Queretaro City markets. Aerobic plate count, coliforms, and Escherichia coli bacteria were quantified, and the presence and number of Salmonella pathogens were also determined. Chia, amaranth, and sesame seeds (1 kg each) were inoculated with a cocktail of five Salmonella strains (∼6 log CFU mL-1) and stored at ambient temperature, and then populations of Salmonella were quantified. The median aerobic plate count contents in chia, amaranth, and sesame seeds were 2.1, 2.4, and 3.8 log CFU g-1, respectively, and the content of coliforms on the seeds ranged from 0.48 to 0.56 log most probable number (MPN) per g. E. coli was present at low concentrations in the three types of seeds. Salmonella was detected in chia (31%), amaranth (15%), and sesame (12%) seeds, and the population ranged from 0.48 to 0.56 log MPN g-1. Salmonella levels decreased through 240 days of storage, showing inactivation rates of 0.017, 0.011, and 0.016 log CFU h-1 in chia, amaranth, and sesame seeds, respectively. The high prevalence of Salmonella in the seeds highlights potential risks for consumers, particularly given that seeds are generally consumed without treatments guaranteeing pathogen inactivation. HIGHLIGHTS
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Affiliation(s)
- Cristian D JuÁrez Arana
- Departamento de Investigación y Posgrado en Alimentos, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas s/n. Col. Las Campanas 76010, Querétaro, Querétaro, México
| | - RamÓn A MartÍnez Peniche
- Departamento de Investigación y Posgrado en Alimentos, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas s/n. Col. Las Campanas 76010, Querétaro, Querétaro, México
| | - Marcela GaytÁn MartÍnez
- Departamento de Investigación y Posgrado en Alimentos, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas s/n. Col. Las Campanas 76010, Querétaro, Querétaro, México
| | - Montserrat HernÁndez Iturriaga
- Departamento de Investigación y Posgrado en Alimentos, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas s/n. Col. Las Campanas 76010, Querétaro, Querétaro, México.,(ORCID: https://orcid.org/0000-0002-3313-5433 [M.H.I.])
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19
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Olaimat AN, Osaili TM, Al-Holy MA, Al-Nabulsi AA, Obaid RS, Alaboudi AR, Ayyash M, Holley R. Microbial safety of oily, low water activity food products: A review. Food Microbiol 2020; 92:103571. [PMID: 32950156 DOI: 10.1016/j.fm.2020.103571] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 05/17/2020] [Accepted: 06/13/2020] [Indexed: 12/25/2022]
Abstract
Oily, low water activity (OL aw) products including tahini (sesame seed paste), halva (tahini halva), peanut butter, and chocolate, have been recently linked to numerous foodborne illness outbreaks and recalls. This review discusses the ingredients used and processing of OL aw products with a view to provide greater understanding of the routes of their contamination with foodborne pathogens and factors influencing pathogen persistence in these foods. Adequate heat treatment during processing may eliminate bacterial pathogens from OL aw foods; however, post-processing contamination commonly occurs. Once these products are contaminated, their high fat and sugar content can enhance pathogen survival for long periods. The physiological basis and survival mechanisms used by pathogens in these products are comprehensively discussed here. Foodborne outbreaks and recalls linked to OL aw foods are summarized and it was observed that serotypes of Salmonella enterica were the predominant pathogens causing illnesses. Further, intervention strategies available to control foodborne pathogens such as thermal inactivation, use of natural antimicrobials, irradiation and hydrostatic pressure are assessed for their usefulness to achieve pathogen control and enhance the safety of OL aw foods. Sanitation, hygienic design of manufacturing facilities, good hygienic practices, and environmental monitoring of OL aw food industries were also discussed.
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Affiliation(s)
- Amin N Olaimat
- Department of Clinical Nutrition and Dietetics, Faculty of Applied Medical Sciences, The Hashemite University, P.O. Box 150459, Zarqa, 13115, Jordan.
| | - Tareq M Osaili
- Department of Clinical Nutrition and Dietetics, College of Health Science, University of Sharjah, Sharjah, United Arab Emirates; Department of Nutrition and Food Technology, Jordan University of Science and Technology, P.O. Box 3030, Irbid, 22110, Jordan.
| | - Murad A Al-Holy
- Department of Clinical Nutrition and Dietetics, Faculty of Applied Medical Sciences, The Hashemite University, P.O. Box 150459, Zarqa, 13115, Jordan
| | - Anas A Al-Nabulsi
- Department of Nutrition and Food Technology, Jordan University of Science and Technology, P.O. Box 3030, Irbid, 22110, Jordan
| | - Reyad S Obaid
- Department of Clinical Nutrition and Dietetics, College of Health Science, University of Sharjah, Sharjah, United Arab Emirates
| | - Akram R Alaboudi
- Department of Pathology and Public Health, Faculty of Veterinary Medicine, Jordan University of Science and Technology, P.O. Box 3030, Irbid, 22110, Jordan
| | - Mutamed Ayyash
- Department of Food, Nutrition and Health, College of Food and Agriculture, United Arab Emirates University (UAEU), Al Ain, UAE
| | - Richard Holley
- Department of Food Science and Human Nutrition, University of Manitoba, Winnipeg, Manitoba, R2J 3L8, Canada
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20
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Dag D, Singh RK, Kong F. Developments in Radio Frequency Pasteurization of Food Powders. FOOD REVIEWS INTERNATIONAL 2020. [DOI: 10.1080/87559129.2020.1775641] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Damla Dag
- Department of Food Science and Technology, The University of Georgia, Athens, GA, USA
| | - Rakesh K. Singh
- Department of Food Science and Technology, The University of Georgia, Athens, GA, USA
| | - Fanbin Kong
- Department of Food Science and Technology, The University of Georgia, Athens, GA, USA
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21
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Barrere V, Tompkins E, Armstrong M, Bird P, Bastin B, Goodridge L. Optimization of Salmonella detection in garlic, onion, cinnamon, red chili pepper powders and green tea. Int J Food Microbiol 2020; 316:108440. [DOI: 10.1016/j.ijfoodmicro.2019.108440] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 10/25/2022]
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22
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Suehr QJ, Chen F, Anderson NM, Keller SE. Effect of Ph On Survival of Escherichia coli O157, Escherichia coli O121, and Salmonella enterica During Desiccation and Short-term Storage. J Food Prot 2020; 83:211-220. [PMID: 31928357 DOI: 10.4315/0362-028x.jfp-19-195] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 10/09/2019] [Indexed: 11/11/2022]
Abstract
ABSTRACT One intrinsic characteristic of low-moisture foods that is frequently overlooked is pH. Although pH affects the survival of microorganisms in high-moisture foods, its influence in low-moisture foods with less available moisture has not been examined. Escherichia coli O157:H7, E. coli O121, Salmonella enterica Anatum, and S. enterica Agona were grown on solid media with and without added glucose, harvested, and then suspended in buffer at pH 4, 5, and 7 for 10 min. All cultures were spotted individually onto cellulose filters and dried in a biohazard cabinet (23 ± 2°C) overnight (24 ± 2 h) and then stored in a 25°C incubator at 33% relative humidity. Populations were examined at regular intervals up to 26 (E. coli) or 29 (Salmonella) days. Additional controls for pH consisted of cultures held in buffer at pH 4, 5, and 7 at 25°C for the same time periods as the desiccated cells. For all strains tested, pH had an effect on survival whether stored dried or in liquid buffer (P < 0.05). However, when grown on solid media, acid adaptation (grown with glucose) before acid treatment did not appear beneficial to Salmonella during desiccation. Instead, both acid-adapted Salmonella serovars appeared less resistant during drying than did non-acid-adapted cells. Once dried, the rates of decline for Salmonella were not significantly different for acid-adapted and nonadapted cells (P > 0.05), indicating similar persistence following desiccation. A reverse trend was observed for E. coli O121; acid adaptation on solid media improved survival during desiccation and subsequent storage at low pH (P < 0.05). E. coli O157:H7 survival was significantly lower than that of either Salmonella or E. coli O121 under all conditions tested. Results indicate that the response to desiccation and pH stress differs between the microorganisms and under different growth conditions. HIGHLIGHTS
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Affiliation(s)
- Quincy J Suehr
- U.S. Food and Drug Administration, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
| | - Fangyu Chen
- Illinois Institute of Technology, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
| | - Nathan M Anderson
- U.S. Food and Drug Administration, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
| | - Susanne E Keller
- U.S. Food and Drug Administration, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
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23
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Campagnollo FB, Furtado MM, Silva BS, Margalho LP, Carminati JA, Sant’Ana AS, Nascimento MS. A quantitative risk assessment model for salmonellosis due to milk chocolate consumption in Brazil. Food Control 2020. [DOI: 10.1016/j.foodcont.2019.106804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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24
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Tsai HC, Ballom KF, Xia S, Tang J, Marks BP, Zhu MJ. Evaluation of Enterococcus faecium NRRL B-2354 as a surrogate for Salmonella during cocoa powder thermal processing. Food Microbiol 2019; 82:135-141. [DOI: 10.1016/j.fm.2019.01.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 01/07/2019] [Accepted: 01/11/2019] [Indexed: 10/27/2022]
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25
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Wiertzema JR, Borchardt C, Beckstrom AK, Dev K, Chen P, Chen C, Vickers Z, Feirtag J, Lee L, Ruan R, Baumler DJ. Evaluation of Methods for Inoculating Dry Powder Foods with Salmonella enterica, Enterococcus faecium, or Cronobacter sakazakii. J Food Prot 2019; 82:1082-1088. [PMID: 31135183 DOI: 10.4315/0362-028x.jfp-18-284] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 02/11/2019] [Indexed: 11/11/2022]
Abstract
Salmonella and Cronobacter are two bacteria of concern in powdered food ingredients with low water activity, due to their ability to remain viable for long periods of time. There is great interest in studying the survival of these bacteria in powdered foods, but discrepancies have been reported between broth-grown and lawn-grown bacterial cells and their thermal resistance and desiccation tolerance once inoculated onto powdered foods. The purpose of this study was to evaluate three different powdered food inoculation methods, two broth-grown and one lawn-grown. To evaluate these methods on three types of powdered food matrices, Salmonella enterica serovar Typhimurium LT2 (ATCC 700720), Salmonella surrogate Enterococcus faecium (NRRL B-2354), and Cronobacter sakazakii (ATCC 29544) were inoculated onto nonfat dry milk powder, organic soy flour, and all-purpose flour using one of the three previously developed inoculation methods. In the first broth-grown method, labeled broth-grown pelletized inoculation, a bacterial cell pellet was added to powdered foods directly and mixed with a sterile wooden stick. The second broth-grown method, labeled broth-grown spray inoculation, used a chromatography reagent sprayer to spray the bacterial cell suspension onto the powdered foods. The third inoculation method, lawn-grown liquid inoculation, made use of a spot inoculation and a stomacher to incorporate each bacterium into the powdered foods. Results indicated that the method of inoculation of each powder impacted repeatability and bacteria survivability postequilibration (4 to 6 days). Broth-grown spray inoculation, regardless of the powder and bacterium, resulted in the highest log reduction, with an average ∼1-log CFU/g reduction following equilibration. Broth-grown pelletized inoculation resulted in the second-highest log reduction (∼0.79 log CFU/g), and finally, lawn-grown liquid inoculation was the most stable inoculation method of the three, with ∼0.52-log CFU/g reduction. Overall, the results from this inoculation study demonstrate that inoculation methodologies impact the desiccation tolerance and homogeneity of C. sakazakii, E. faecium, and Salmonella Typhimurium LT2.
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Affiliation(s)
- Justin R Wiertzema
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota 55108
| | - Christian Borchardt
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota 55108
| | - Anna K Beckstrom
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota 55108
| | - Kamal Dev
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota 55108
| | - Paul Chen
- Center for Biorefining, and Department of Bioproducts and Biosystems Engineering, University of Minnesota, St. Paul, Minnesota 55108
| | - Chi Chen
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota 55108
| | - Zata Vickers
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota 55108
| | - Joellen Feirtag
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota 55108
| | - Laurence Lee
- Biotechnology Institute, University of Minnesota, St. Paul, Minnesota 55108
| | - Roger Ruan
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota 55108.,Center for Biorefining, and Department of Bioproducts and Biosystems Engineering, University of Minnesota, St. Paul, Minnesota 55108
| | - David J Baumler
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota 55108.,Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota 55108.,LZL Engineering, Inc., 760 Crestview Lane, Owatonna, Minnesota 55060, USA
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26
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Abstract
Spices in the desiccated state provide an environment that allows the survival of many foodborne pathogens. Currently, the incidence of pathogen-positive spices imported into the United States is 1.9 times higher than for any other imported food. Correspondingly, imported spices have been associated with numerous foodborne outbreaks and multiple product recalls. Despite the association with recalls and outbreaks, the actual pathogen populations in spices, when found, are frequently extremely small. In addition to pathogenic bacterial species, toxigenic molds have been frequently recovered from spices, and aflatoxins have been found in as many as 58% of the spices sampled. The presence of toxigenic molds is especially problematic to the immunocompromised or those on immunosuppressive therapy and has been linked to gut aspergillosis. Numerous detection methods, including both traditional and advanced DNA regimes, are being tested to optimize recovery of pathogens from spices. Further, a number of new inactivation intervention methods to decontaminate spices are examined and discussed.
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Affiliation(s)
- Joshua B. Gurtler
- Eastern Regional Research Center, United States Department of Agriculture, Wyndmoor, Pennsylvania 10460, USA
| | - Susanne E. Keller
- United States Food and Drug Administration, Bedford Park, Illinois 60501, USA
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27
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Crucello A, Furtado MM, Chaves MDR, Sant'Ana AS. Transcriptome sequencing reveals genes and adaptation pathways in Salmonella Typhimurium inoculated in four low water activity foods. Food Microbiol 2019; 82:426-435. [PMID: 31027802 DOI: 10.1016/j.fm.2019.03.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 03/09/2019] [Accepted: 03/14/2019] [Indexed: 11/25/2022]
Abstract
Salmonella enterica serotypes have been reported as the agent of various outbreaks occurred after the consumption of low water activity (aw) foods. When the pathogen encounters harsh conditions, several regulatory networks are activated through dynamic differential gene expression that lead to cell survival for prolonged periods. In this work, the transcriptome of S. enterica serovar Typhimurium using RNA-Seq, after cells' inoculation in four distinct types of low aw foods (milk chocolate, powdered milk, black pepper, and dried pet food), following storage at 25 °C per 24 and 72 h was studied. The findings of this study suggest that gene regulation is influenced by the food composition mainly in the first 24 h post-inoculum, proceeded by the induction of similar genes shared among all samples. It was possible to evaluate the differences on each type of food matrix regarding the bacteria adaptation, as well as the similarities provoked by low aw. The results reveal genes that may play key roles in response to desiccation in Salmonella, as well as the pathways in which they are involved.
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Affiliation(s)
- Aline Crucello
- Department of Food Science, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - Marianna M Furtado
- Department of Food Science, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - Monyca D R Chaves
- Department of Food Science, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - Anderson S Sant'Ana
- Department of Food Science, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil.
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28
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Kharel K, Yemmireddy VK, Graham CJ, Prinyawiwatkul W, Adhikari A. Hot water treatment as a kill-step to inactivate Escherichia coli O157:H7, Salmonella enterica, Listeria monocytogenes and Enterococcus faecium on in-shell pecans. Lebensm Wiss Technol 2018. [DOI: 10.1016/j.lwt.2018.07.048] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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29
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Jin Y, Pickens SR, Hildebrandt IM, Burbick SJ, Grasso-Kelley EM, Keller SE, Anderson NM. Thermal Inactivation of Salmonella Agona in Low-Water Activity Foods: Predictive Models for the Combined Effect of Temperature, Water Activity, and Food Component. J Food Prot 2018; 81:1411-1417. [PMID: 30059253 DOI: 10.4315/0362-028x.jfp-18-041] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Salmonella can survive in low-moisture, high-protein, and high-fat foods for several years. Despite nationwide outbreaks and recalls due to the presence of Salmonella in low-moisture foods, information on thermal inactivation of Salmonella in these products is limited. This project evaluated the impact of water activity (aw), temperature, and food composition on thermal inactivation of Salmonella enterica serovar Agona in defined high-protein and high-fat model food matrices. Each matrix was inoculated with Salmonella Agona and adjusted to obtain a target aw, ranging from 0.50 to 0.98. Samples were packed into aluminum test cells and heated (52 to 90°C) under isothermal conditions. Survival of Salmonella Agona was detected on tryptic soy agar with 0.6% yeast extract. Complex influences by food composition, aw, and temperature resulted in significantly different ( P < 0.05) thermal resistance of Salmonella for the conditions tested. It was estimated that the same point temperatures at which the D-values of the two matrices at each aw (0.63, 0.73, 0.81, and 0.90) were identical were 79.48, 71.28, 69.62, and 38.42°C, respectively. Above these temperatures, the D-values in high-protein matrices were larger than the D-values in high-fat matrices at each aw. Below these temperatures, the inverse relationship was observed. A correlation between temperature and aw existed on the basis of the level of fat or protein in the food, showing that these compositional factors must be accounted for when predicating thermal inactivation of Salmonella in foods.
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Affiliation(s)
- Yuqiao Jin
- 1 Illinois Institute of Technology, Institute of Food Safety and Health, and
| | - Shannon R Pickens
- 1 Illinois Institute of Technology, Institute of Food Safety and Health, and
| | - Ian M Hildebrandt
- 2 U.S. Food and Drug Administration, Division of Food Processing Science and Technology, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
| | - Stephen J Burbick
- 2 U.S. Food and Drug Administration, Division of Food Processing Science and Technology, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
| | | | - Susanne E Keller
- 2 U.S. Food and Drug Administration, Division of Food Processing Science and Technology, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
| | - Nathan M Anderson
- 2 U.S. Food and Drug Administration, Division of Food Processing Science and Technology, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
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30
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Moraes JO, Cruz EA, Souza EGF, Oliveira TCM, Alvarenga VO, Peña WEL, Sant'Ana AS, Magnani M. Predicting adhesion and biofilm formation boundaries on stainless steel surfaces by five Salmonella enterica strains belonging to different serovars as a function of pH, temperature and NaCl concentration. Int J Food Microbiol 2018; 281:90-100. [PMID: 29843904 DOI: 10.1016/j.ijfoodmicro.2018.05.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 04/06/2018] [Accepted: 05/10/2018] [Indexed: 12/20/2022]
Abstract
This study aimed to assess the capability of 97 epidemic S. enterica strains belonging to 18 serovars to form biofilm. Five strains characterized as strong biofilm-producers, belonging to distinct serovars (S. Enteritidis 132, S. Infantis 176, S. Typhimurium 177, S. Heidelberg 281 and S. Corvallis 297) were assayed for adhesion/biofilm formation on stainless steel surfaces. The experiments were conducted in different combinations of NaCl (0, 2, 4, 5, 6, 8 and 10% w/v), pH (4, 5, 6 and 7) and temperatures (8 °C, 12 °C, 20 °C and 35 °C). Only adhesion was assumed to occur when S. enterica counts were ≥3 and <5 log CFU/cm2, whereas biofilm formation was defined as when the counts were ≥5 log CFU/cm2. The binary responses were used to develop models to predict the probability of adhesion/biofilm formation on stainless steel surfaces by five strains belonging to different S. enterica serovars. A total of 99% (96/97) of the tested S. enterica strains were characterized as biofilm-producers in the microtiter plate assays. The ability to form biofilm varied (P < 0.05) within and among the different serovars. Among the biofilm-producers, 21% (20/96), 45% (43/96), and 35% (34/96) were weak, moderate and strong biofilm-producers, respectively. The capability for adhesion/biofilm formation on stainless steel surfaces under the experimental conditions studied varied among the strains studied, and distinct secondary models were obtained to describe the behavior of the five S. enterica tested. All strains showed adhesion at pH 4 up to 4% of NaCl and at 20 °C and 35 °C. The probability of adhesion decreased when NaCl concentrations were >8% and at 8 °C, as well as in pH values ≤ 5 and NaCl concentrations > 6%, for all tested strains. At pH 7 and 6, biofilm formation for S. Enteritidis, S. Infantis, S. Typhimurium, S. Heidelberg was observed up to 6% of NaCl at 35 °C and 20 °C. The predicted boundaries for adhesion were pH values < 5 and NaCl ≥ 4% and at temperatures <20 °C. For biofilm formation, the predicted boundaries were pH values < 5 and NaCl concentrations ≥ 2% and at temperatures <20 °C for all strains. The secondary models obtained describe the variability in boundaries of adhesion and biofilm formation on stainless steel by five strains belonging to different S. enterica serovars. The boundary models can be used to predict adhesion and biofilm formation ability on stainless steel by S. enterica as affected by pH, NaCl and temperature.
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Affiliation(s)
- Juliana O Moraes
- Department of Agroindustry, Federal Institute of Alagoas, Piranhas, State of Alagoas, Brazil
| | - Ellen A Cruz
- Department of Agroindustry, Federal Institute of Alagoas, Piranhas, State of Alagoas, Brazil
| | - Enio G F Souza
- Department of Agroecology, Federal Institute of Alagoas, Piranhas, State of Alagoas, Brazil
| | - Tereza C M Oliveira
- Department of Food Science and Technology, State University of Londrina, Paraná, Brazil
| | - Verônica O Alvarenga
- Department of Food Science, Faculty of Food Engineering, University of Campinas, Campinas, State of São Paulo, Brazil
| | - Wilmer E L Peña
- Department of Food Technology, Federal University of Viçosa, Minas Gerais, Brazil
| | - Anderson S Sant'Ana
- Department of Food Science, Faculty of Food Engineering, University of Campinas, Campinas, State of São Paulo, Brazil
| | - Marciane Magnani
- Laboratory of Microbial Processes in Foods, Department of Food Engineering, Technology Center, Federal University of Paraíba, João Pessoa, Paraíba, Brazil.
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31
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Nascimento M, Carminati J, Silva I, Silva D, Bernardi A, Copetti M. Salmonella , Escherichia coli and Enterobacteriaceae in the peanut supply chain: From farm to table. Food Res Int 2018; 105:930-935. [DOI: 10.1016/j.foodres.2017.12.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/05/2017] [Accepted: 12/08/2017] [Indexed: 11/29/2022]
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32
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Mandal RK, Kwon YM. Global Screening of Salmonella enterica Serovar Typhimurium Genes for Desiccation Survival. Front Microbiol 2017; 8:1723. [PMID: 28943871 PMCID: PMC5596212 DOI: 10.3389/fmicb.2017.01723] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 08/24/2017] [Indexed: 01/13/2023] Open
Abstract
Salmonella spp., one of the most common foodborne bacterial pathogens, has the ability to survive under desiccation conditions in foods and food processing facilities for years. This raises the concerns of Salmonella infection in humans associated with low water activity foods. Salmonella responds to desiccation stress via complex pathways involving immediate physiological actions as well as coordinated genetic responses. However, the exact mechanisms of Salmonella to resist desiccation stress remain to be fully elucidated. In this study, we screened a genome-saturating transposon (Tn5) library of Salmonella Typhimurium (S. Typhimurium) 14028s under the in vitro desiccation stress using transposon sequencing (Tn-seq). We identified 61 genes and 6 intergenic regions required to overcome desiccation stress. Salmonella desiccation resistance genes were mostly related to energy production and conversion; cell wall/membrane/envelope biogenesis; inorganic ion transport and metabolism; regulation of biological process; DNA metabolic process; ABC transporters; and two component system. More than 20% of the Salmonella desiccation resistance genes encode either putative or hypothetical proteins. Phenotypic evaluation of 12 single gene knockout mutants showed 3 mutants (atpH, atpG, and corA) had significantly (p < 0.02) reduced survival as compared to the wild type during desiccation survival. Thus, our study provided new insights into the molecular mechanisms utilized by Salmonella for survival against desiccation stress. The findings might be further exploited to develop effective control strategies against Salmonella contamination in low water activity foods and food processing facilities.
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Affiliation(s)
- Rabindra K Mandal
- Department of Poultry Science, University of ArkansasFayetteville, AR, United States
| | - Young M Kwon
- Department of Poultry Science, University of ArkansasFayetteville, AR, United States.,Cell and Molecular Biology Program, University of ArkansasFayetteville, AR, United States
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33
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Tadapaneni RK, Syamaladevi RM, Villa-Rojas R, Tang J. Design of a novel test cell to study the influence of water activity on the thermal resistance of Salmonella in low-moisture foods. J FOOD ENG 2017. [DOI: 10.1016/j.jfoodeng.2017.03.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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34
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Zhang Y, Keller SE, Grasso-Kelley EM. Fate of Salmonella throughout Production and Refrigerated Storage of Tahini. J Food Prot 2017; 80:940-946. [PMID: 28463084 DOI: 10.4315/0362-028x.jfp-16-507] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Tahini, a low-moisture food that is made from sesame seeds, has been implicated in outbreaks of salmonellosis. In this study, the fate of Salmonella was determined through an entire process for the manufacture of tahini, including a 24-h seed soaking period before roasting, subsequent grinding, and storage at refrigeration temperature. Salmonella populations increased by more than 3 log CFU/g during a 24-h soaking period, reaching more than 7 log CFU/g. Survival of Salmonella during roasting at three temperatures, 95, 110, and 130°C, was assessed using seeds on which Salmonella was grown. Salmonella survival was impacted both by temperature and the water activity (aw) at the beginning of the roasting period. When roasted at 130°C with a high initial aw (≥0.90) and starting Salmonella populations of ∼8.5 log CFU/g, populations quickly decreased below detection limits within the first 10 min. However, when the seeds were reduced to an aw of 0.45 before roasting at the same temperature, 3.5 log CFU/g remained on the seeds after 60 min. In subsequent storage studies, seeds were roasted at 130°C for 15 min before processing into tahini. For the storage studies, tahini was inoculated using two methods. The first method used seeds on which Salmonella was first grown before roasting. In the second method, Salmonella was inoculated into the tahini after manufacture. All tahini was stored for 119 days at 4°C. No change in Salmonella populations was recorded for tahini throughout the entire 119 days regardless of the inoculation method used. These combined results indicate the critical importance of aw during a roasting step during tahini manufacture. Salmonella that survive roasting will likely remain viable throughout the normal shelf life of tahini.
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Affiliation(s)
- Yangjunna Zhang
- 1 Illinois Institute of Technology, Institute for Food Safety and Health, 6502 South Archer Road, Bedford Park, Illinois 60501
| | - Susanne E Keller
- 2 U.S. Food and Drug Administration, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
| | - Elizabeth M Grasso-Kelley
- 1 Illinois Institute of Technology, Institute for Food Safety and Health, 6502 South Archer Road, Bedford Park, Illinois 60501
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35
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Wu S, Ricke SC, Schneider KR, Ahn S. Food safety hazards associated with ready-to-bake cookie dough and its ingredients. Food Control 2017. [DOI: 10.1016/j.foodcont.2016.10.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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36
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Hildebrandt IM, Hu C, Grasso-Kelley EM, Ye P, Anderson NM, Keller SE. Dry Transfer Inoculation of Low-Moisture Spices Containing Antimicrobial Compounds. J Food Prot 2017; 80:338-344. [PMID: 28221981 DOI: 10.4315/0362-028x.jfp-16-279] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Inoculation of a food product for use in subsequent validation studies typically makes use of a high concentration cocktail of microorganisms suspended in aqueous media. However, this inoculation method may prove difficult particularly when the food product is a low-moisture food containing antimicrobial compounds, such as some dried spices. In this study, a dry transfer method for inoculation of clove powder, oregano leaves, ginger powder, and ground black pepper with a five-serovar cocktail of Salmonella was developed and compared with a traditional aqueous inoculation procedure. Spices were inoculated at three levels, 10, 8, and 6 log CFU/g, by using both an aqueous suspension of Salmonella and a dry transfer of Salmonella from previously inoculated silica beads. At the highest inoculation level, the dry transfer method resulted in a significantly higher microbial load (P < 0.05) for ground cloves and oregano, but not for ginger and ground black pepper. At the intermediate inoculation level, differences were apparent only for ginger and black pepper. Inoculation levels of 6 log CFU/g resulted in recoveries below detection limits for both methods of inoculation. Additional examination on the survival of Salmonella on silica beads after inoculation and in clove powder after dry transfer from silica beads showed linear rates of decline, with a rate of -0.011 log CFU/g/day for beads and -0.015 log CFU/g/day for clove powder. The results suggest that dry transfer of Salmonella via inoculated silica beads is a viable alternative when traditional aqueous inoculation is not feasible.
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Affiliation(s)
- Ian M Hildebrandt
- U.S. Food and Drug Administration, 6502 South Archer Road, Bedford Park, Illinois 60501
| | - Chuxuan Hu
- Illinois Institute of Technology, Institute for Food Safety and Health, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
| | - Elizabeth M Grasso-Kelley
- Illinois Institute of Technology, Institute for Food Safety and Health, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
| | - Peiran Ye
- Illinois Institute of Technology, Institute for Food Safety and Health, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
| | - Nathan M Anderson
- U.S. Food and Drug Administration, 6502 South Archer Road, Bedford Park, Illinois 60501
| | - Susanne E Keller
- U.S. Food and Drug Administration, 6502 South Archer Road, Bedford Park, Illinois 60501
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37
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Hildebrandt IM, Marks BP, Ryser ET, Villa-Rojas R, Tang J, Garces-Vega FJ, Buchholz SE. Effects of Inoculation Procedures on Variability and Repeatability of Salmonella Thermal Resistance in Wheat Flour. J Food Prot 2016; 79:1833-1839. [PMID: 28221914 DOI: 10.4315/0362-028x.jfp-16-057] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Limited prior research has shown that inoculation methods affect thermal resistance of Salmonella in low-moisture foods; however, these effects and their repeatability have not been systematically quantified. Consequently, method variability across studies limits utility of individual data sets and cross-study comparisons. Therefore, the objective was to evaluate the effects of inoculation methodologies on stability and thermal resistance of Salmonella in a low-moisture food (wheat flour), and the repeatability of those results, based on data generated by two independent laboratories. The experimental design consisted of a cross-laboratory comparison, both conducting isothermal Salmonella inactivation studies in wheat flour (~0.45 water activity, 80°C), utilizing five different inoculation methods: (i) broth-based liquid inoculum, (ii) lawn-based liquid inoculum, (iii) lawn-based pelletized inoculum, (iv) direct harvest of lawn culture with wheat flour, and (v) fomite transfer of a lawn culture. Inoculated wheat flour was equilibrated ~5 days to ~0.45 water activity and then was subjected to isothermal treatment (80°C) in aluminum test cells. Results indicated that inoculation method impacted repeatability, population stability, and inactivation kinetics (α = 0.05), regardless of laboratory. Salmonella inoculated with the broth-based liquid inoculum method and the fomite transfer of a lawn culture method exhibited instability during equilibration. Lawn-based cultures resulted in stable populations prior to thermal treatment; however, the method using direct harvest of lawn culture with wheat flour yielded different D-values across the laboratories (α = 0.05), which was attributed to larger potential impact of operator variability. The lawn-based liquid inoculum and the lawn-based pelletized inoculum methods yielded stable inoculation levels and repeatable D-values (~250 and ~285 s, respectively). Also, inoculation level (3 to 8 log CFU/g) did not affect D-values (using the lawn-based liquid inoculum method). Overall, the results demonstrate that inoculation methods significantly affect Salmonella population kinetics and subsequent interpretation of thermal inactivation data for low-moisture foods.
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Affiliation(s)
- Ian M Hildebrandt
- Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan 48824
| | - Bradley P Marks
- Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan 48824
| | - Elliot T Ryser
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824
| | - Rossana Villa-Rojas
- Department of Biological Systems Engineering, Washington State University, Pullman, Washington 99164, USA
| | - Juming Tang
- Department of Biological Systems Engineering, Washington State University, Pullman, Washington 99164, USA
| | - Francisco J Garces-Vega
- Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan 48824
| | - Sarah E Buchholz
- Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan 48824
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38
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Inactivation of Salmonella, Listeria monocytogenes and Enterococcus faecium NRRL B-2354 in a selection of low moisture foods. Int J Food Microbiol 2016; 231:16-25. [DOI: 10.1016/j.ijfoodmicro.2016.04.022] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 04/12/2016] [Accepted: 04/16/2016] [Indexed: 11/21/2022]
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39
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Carminati JDA, Amorim Neto DP, Morishita KN, Takano LV, Olivier Bernardi A, Copetti MV, do Nascimento MDS. Microbiological contamination in peanut confectionery processing plants. J Appl Microbiol 2016; 121:1071-8. [PMID: 27427217 DOI: 10.1111/jam.13235] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 07/06/2016] [Accepted: 07/14/2016] [Indexed: 10/21/2022]
Abstract
AIMS In order to investigate Enterobacteriaceae, coliforms, Escherichia coli and Salmonella contamination, a survey was conducted at three peanut confectionery processing companies (A, B and C) in Brazil. METHODS AND RESULTS Samples of different peanut confectionery products (n = 59), peanut raw material (n = 30), manufacturing environment (n = 116) and workers' hand surfaces (n = 12) were analysed. Salmonella and E. coli were not detected in any final product or raw material analysed. Enterobacteriaceae was isolated from 15% of final products. Coliforms were detected in only one sample. Referring to the raw material, six samples showed contamination by Enterobacteriaceae and three samples by coliforms. For the process environment, 19% and 11% of samples presented Enterobacteriaceae and coliforms. Escherichia coli was detected in 5% of samples, and one of these samples tested positive for Salmonella; this strain was serotyping as S. Heidelberg. All food handlers surveyed in Company C showed Enterobacteriaceae and coliforms on their hands. Escherichia coli was isolated from one food worker's hand. CONCLUSION The results showed that the manufacturing environment, including food handlers were considered the main sources for possible contamination of peanut confectionery products. SIGNIFICANCE AND IMPACT OF THE STUDY This has been the first study to investigate the occurrence of Salmonella and other Enterobacteriaceae throughout peanut confectionery processing lines. The results might be used to assist risk assessment studies and to establish more effective control measures.
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Affiliation(s)
- J de A Carminati
- Department of Food Technology, School of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - D P Amorim Neto
- Department of Food Technology, School of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - K N Morishita
- Department of Food Technology, School of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - L V Takano
- Department of Food Technology, School of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - A Olivier Bernardi
- Department of Food Technology and Science, Federal University of Santa Maria, Santa Maria, RS, Brazil
| | - M V Copetti
- Department of Food Technology and Science, Federal University of Santa Maria, Santa Maria, RS, Brazil
| | - M da S do Nascimento
- Department of Food Technology, School of Food Engineering, University of Campinas, Campinas, SP, Brazil.
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40
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Water activity change at elevated temperatures and thermal resistance of Salmonella in all purpose wheat flour and peanut butter. Food Res Int 2016. [DOI: 10.1016/j.foodres.2016.01.008] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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41
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Lambertini E, Mishra A, Guo M, Cao H, Buchanan RL, Pradhan AK. Modeling the long-term kinetics of Salmonella survival on dry pet food. Food Microbiol 2016; 58:1-6. [PMID: 27217351 DOI: 10.1016/j.fm.2016.02.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 01/29/2016] [Accepted: 02/05/2016] [Indexed: 10/22/2022]
Abstract
Due to multiple outbreaks and large-scale product recalls, Salmonella has emerged as a priority pathogen in dry pet food and treats. However, little data are available to quantify risks posed by these classes of products to both pets and their owners. Specifically, the kinetics of Salmonella survival on complex pet food matrices are not available. This study measured the long-term kinetics of Salmonella survival on a dry pet food under storage conditions commonly encountered during production, retail, and in households (aw < 0.60, 23 °C). A Salmonella enterica cocktail of 12 strains isolated from dry pet foods and treats was used to inoculate commercial dry dog food. Salmonella was enumerated on non-selective (BHI) and selective (XLD and BS) media. Results at 570 days indicated an initial relatively rapid decline (up to 54 days), followed by a much slower extended decline phase. The Weibull model provided a satisfactory fit for time series of Log-transformed Salmonella counts from all three media (δ: mean 4.65 day/Log (CFU/g); p: mean 0.364 on BHI). This study provides a survival model that can be applied in quantitative risk assessment models.
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Affiliation(s)
- Elisabetta Lambertini
- Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA; Center for Food Safety and Security Systems, University of Maryland, College Park, MD 20742, USA
| | - Abhinav Mishra
- Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA
| | - Miao Guo
- Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA
| | - Huilin Cao
- Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA
| | - Robert L Buchanan
- Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA; Center for Food Safety and Security Systems, University of Maryland, College Park, MD 20742, USA
| | - Abani K Pradhan
- Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA; Center for Food Safety and Security Systems, University of Maryland, College Park, MD 20742, USA.
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42
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43
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Fudge J, Dunn M, Pike O, Robison R, Steele F. The isolation and identification of Pantoea dispersa strain JFS as a non-pathogenic surrogate for Salmonella Typhimurium phage type 42 in flour. Int J Food Microbiol 2016; 219:1-6. [DOI: 10.1016/j.ijfoodmicro.2015.11.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Revised: 11/04/2015] [Accepted: 11/21/2015] [Indexed: 01/11/2023]
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44
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The response of foodborne pathogens to osmotic and desiccation stresses in the food chain. Int J Food Microbiol 2016; 221:37-53. [PMID: 26803272 DOI: 10.1016/j.ijfoodmicro.2015.12.014] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 12/22/2015] [Accepted: 12/30/2015] [Indexed: 12/24/2022]
Abstract
In combination with other strategies, hyperosmolarity and desiccation are frequently used by the food processing industry as a means to prevent bacterial proliferation, and particularly that of foodborne pathogens, in food products. However, it is increasingly observed that bacteria, including human pathogens, encode mechanisms to survive and withstand these stresses. This review provides an overview of the mechanisms employed by Salmonella spp., Shiga toxin producing E. coli, Cronobacter spp., Listeria monocytogenes and Campylobacter spp. to tolerate osmotic and desiccation stresses and identifies gaps in knowledge which need to be addressed to ensure the safety of low water activity and desiccated food products.
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45
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Survival of Salmonella spp. in low water activity chicken base paste and powder formulated at different salt levels. Food Control 2016. [DOI: 10.1016/j.foodcont.2015.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Ryan G, Roof S, Post L, Wiedmann M. Evaluation of Rapid Molecular Detection Assays for Salmonella in Challenging Food Matrices at Low Inoculation Levels and Using Difficult-to-Detect Strains. J Food Prot 2015; 78:1632-41. [PMID: 26319716 DOI: 10.4315/0362-028x.jfp-15-098] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Assays for detection of foodborne pathogens are generally initially evaluated for performance in validation studies carried out according to guidelines provided by validation schemes (e.g., AOAC International or the International Organization for Standardization). End users often perform additional validation studies to evaluate the performance of assays in specific matrices (e.g., specific foods or raw material streams of interest) and with specific pathogen strains. However, these types of end-user validations are typically not well defined. This study was conducted to evaluate a secondary end user validation of four AOAC-validated commercial rapid detection assays (an isothermal nucleic acid amplification, an immunoassay, and two PCR-based assays) for their ability to detect Salmonella in two challenging matrices (dry pet food and dark chocolate). Inclusivity was evaluated with 68 diverse Salmonella strains at low population levels representing the limit of detection (LOD) for each assay. One assay detected all strains at the LOD, two assays detected multiple strains only at 10 times the LOD, and the fourth assay failed to detect two strains (Salmonella bongori and S. enterica subsp. houtenae) even at 1,000 times the LOD; this assay was not further evaluated. The three remaining assays were subsequently evaluated for their ability to detect five selected Salmonella strains in food samples contaminated at fractional levels. Unpaired comparisons revealed no significant difference between the results for each given assay and the results obtained with the reference assay. However, analysis of paired culture-confirmed results revealed assay false-negative rates of 4 to 26% for dry pet food and 12 to 16% for dark chocolate. Overall, our data indicate that rapid assays may have high false-negative rates when performance is evaluated under challenging conditions, including low-moisture matrices, strains that are difficult to detect, injured cells, and low inoculum levels.
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Affiliation(s)
- Gina Ryan
- Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853, USA, U.S. Food and Drug Administration, College Park, MD 20740, USA
| | - Sherry Roof
- Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853, USA
| | - Laurie Post
- Mars Global Food Safety Center, Huairou, Beijing, People's Republic of China
| | - Martin Wiedmann
- Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853, USA.
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McEgan R, Danyluk MD. Evaluation of aqueous and alcohol-based quaternary ammonium sanitizers for inactivating Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes on peanut and pistachio shells. Food Microbiol 2015; 47:93-8. [DOI: 10.1016/j.fm.2014.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 11/20/2014] [Accepted: 11/21/2014] [Indexed: 10/24/2022]
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Lambertini E, Buchanan RL, Narrod C, Pradhan AK. Transmission of Bacterial Zoonotic Pathogens between Pets and Humans: The Role of Pet Food. Crit Rev Food Sci Nutr 2015; 56:364-418. [DOI: 10.1080/10408398.2014.902356] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Santillana Farakos SM, Schaffner DW, Frank JF. Predicting survival of Salmonella in low-water activity foods: an analysis of literature data. J Food Prot 2014; 77:1448-61. [PMID: 25198835 DOI: 10.4315/0362-028x.jfp-14-013] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Factors such as temperature, water activity (aw), substrate, culture media, serotype, and strain influence the survival of Salmonella in low-aw foods. Predictive models for Salmonella survival in low-aw foods at temperatures ranging from 21 to 80(u) C and water activities below 0.6 were previously developed. Literature data on survival of Salmonella in low-aw foods were analyzed in the present study to validate these predictive models and to determine global influencing factors. The results showed the Weibull model provided suitable fits to the data in 75% of the curves as compared with the log-linear model. The secondary models predicting the time required for log-decimal reduction (log δ) and shape factor (log β) values were useful in predicting the survival of Salmonella in low-aw foods. Statistical analysis indicated overall fail-safe secondary models, with 88% of the residuals in the acceptable and safe zones (<0.5 log CFU) and a 59% correlation coefficient (R(2) = 0.35). A high variability in log δ-values and log β-values was observed, emphasizing the importance of experimental design. Factors of significant influence on the times required for first log-decimal reduction included temperature, aw, product, and serotype. Log β-values were significantly influenced by serotype, the type of inoculum (wet or dry), and whether the recovery media was selective or not. The results of this analysis provide a general overview of survival kinetics of Salmonella in low-aw foods and its influencing factors.
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Affiliation(s)
- Sofia M Santillana Farakos
- Department of Food Science and Technology, The University of Georgia, Athens, Georgia 30602-2610, USA; Office of Foods and Veterinary Medicine, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Donald W Schaffner
- Department of Food Science, Rutgers University, New Brunswick, New Jersey 08901-8520, USA
| | - Joseph F Frank
- Department of Food Science and Technology, The University of Georgia, Athens, Georgia 30602-2610, USA.
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Beuchat LR, Mann DA. Survival of salmonella on dried fruits and in aqueous dried fruit homogenates as affected by temperature. J Food Prot 2014; 77:1102-9. [PMID: 24988015 DOI: 10.4315/0362-028x.jfp-13-549] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A study was done to determine the ability of Salmonella to survive on dried cranberries, raisins, and strawberries and in date paste, as affected by storage temperature. Acid-adapted Salmonella, initially at 6.57 to 7.01 log CFU/g, was recovered from mist-inoculated cranberries (water activity [aw] 0.47) and raisins (aw 0.46) stored at 25°C for 21 days but not 42 days, strawberries (aw 0.21) for 42 days but not 84 days, and date paste (aw 0.69) for 84 days but not 126 days. In contrast, the pathogen was detected in strawberries stored at 4°C for 182 days (6 months) but not 242 days (8 months) and in cranberries, date paste, and raisins stored for 242 days. Surface-grown cells survived longer than broth-grown cells in date paste. The order of rate of inactivation at 4°C was cranberry > strawberry > raisin > date paste. Initially at 2.18 to 3.35 log CFU/g, inactivation of Salmonella on dry (sand)&ndash inoculated fruits followed trends similar to those for mist-inoculated fruits. Survival of Salmonella in aqueous homogenates of dried fruits as affected by fruit concentration and temperature was also studied. Growth was not observed in 10% (aw 0.995 to 0.999) and 50% (aw 0.955 to 0.962) homogenates of the four fruits held at 4°C, 50% homogenates at 25°C, and 10% cranberry and strawberry homogenates at 25°C. Growth of the pathogen in 10% date paste and raisin homogenates stored at 25°C was followed by rapid inactivation. Results of these studies suggest the need to subject dried fruits that may be contaminated with Salmonella to a lethal process and prevent postprocess contamination before they are eaten out-of-hand or used as ingredients in ready-to-eat foods. Observations showing that Salmonella can grow in aqueous homogenates of date paste and raisins emphasize the importance of minimizing contact of these fruits with high-moisture environments during handling and storage.
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Affiliation(s)
- Larry R Beuchat
- Center for Food Safety and Department of Food Science and Technology, University of Georgia, 1109 Experiment Street, Griffin, Georgia 30223-1797, USA.
| | - David A Mann
- Center for Food Safety and Department of Food Science and Technology, University of Georgia, 1109 Experiment Street, Griffin, Georgia 30223-1797, USA
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