1
|
Bozatli SB, Dikici A, Ergönül B. Determination of the changes in the gastric fluid endurance of O157 and non-O157 Shiga toxin-producing Escherichia coli during storage of experimentally produced beef frankfurter. JOURNAL OF FOOD SCIENCE AND TECHNOLOGY 2021; 58:3086-3093. [PMID: 34294971 DOI: 10.1007/s13197-020-04812-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 09/08/2020] [Accepted: 09/17/2020] [Indexed: 11/24/2022]
Abstract
Resistance of Shiga toxin-producing Escherichia coli (STEC) O157:H7 and serogroups O103, O26 and O145 to synthetic gastric fluid (SGF, pH 1.5) were investigated during frankfurter storage. Pathogens were inoculated (5 ± 1 log10 cfu g-1) on frankfurters and frankfurters were stored at 4 °C for 75 days in vacuum packages. Population changes of the competitive flora and STEC, changes in the pH of the frankfurters and resistance of STEC to SGF were monitored on days 0, 15, 30, 45, 60 and 75 of frankfurter storage. Direct synthetic gastric fluid (DSGF) challenges were also conducted to assess pathogen resistance without being effected by frankfurters, by inoculating pathogen cultures directly into SGF. Results showed that acid resistance of O145 and O26 was stronger than that of O103 and O157 during frankfurter storage. Resistance of O103 to SGF was better than that of O157 during frankfurter storage but, was similar to that of O157 during DSGF challenges. Results indicate that acid resistance of some strains of STEC pathogens might differentiate during storage of frankfurters. Different resistance capabilities to SGF were observed in the STEC strains when inoculated and stored on frankfurters than directly inoculated in the SGF.
Collapse
Affiliation(s)
- Sümeyye Betül Bozatli
- Department of Food Engineering, Faculty of Engineering, Manisa Celal Bayar University, Manisa, Turkey
| | - Abdullah Dikici
- Department of Food Engineering, Faculty of Engineering, Uşak University, Uşak, Turkey
| | - Bülent Ergönül
- Department of Food Engineering, Faculty of Engineering, Manisa Celal Bayar University, Manisa, Turkey
| |
Collapse
|
2
|
Yu L, Zhang S, Xu Y, Mi X, Xing T, Li J, Zhang L, Gao F, Jiang Y. Acid resistance of E. coli O157:H7 and O26:H11 exposure to lactic acid revealed by transcriptomic analysis. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2020.110352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
3
|
Acuff JC, Waterman K, Ramakrishnan J, Ponder MA. Thermal Resistance of Single Strains of Shiga Toxin-Producing Escherichia coli O121:H19 and O157:H7 Based on Culture Preparation Method and Osmolyte-Reduced Water Activity. J Food Prot 2021; 84:122-127. [PMID: 32916717 DOI: 10.4315/jfp-20-122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 09/05/2020] [Indexed: 11/11/2022]
Abstract
ABSTRACT Bacterial exposure to stress, such as reduced water activity (aw), can increase thermal resistance. Pathogen thermal resistance studies on low-aw foods use a variety of methods to inoculate food, as well as strategies to reduce aw, which can influence observations. This study investigated effects of culture preparation method and osmolyte-induced aw on thermal resistance of two Shiga toxin-producing Escherichia coli (STEC) strains (O121:H19 and O157:H7) challenged with isothermal conditions, determining D- and z-values for each isolate (56, 59, and 62°C). Tryptic soy broth (TSB) and agar (lawn cultures) were compared. D-values of broth cultures were significantly and consistently larger than those of lawn cultures, and O121 was significantly more resistant than O157, but only at 56°C (P < 0.05). To compare potential effects of aw on STEC thermal resistance, cells were suspended in osmolyte solutions with varying aw: high (TSB, aw 0.99), intermediate (61% glycerol or 26% NaCl, aw 0.75), and low (82% glycerol, aw 0.5). In most instances, STEC strains in high-aw broth exhibited greater heat resistance compared to reduced-aw solutions, with the exception of the glycerol intermediate-aw solution (aw 0.75). Magnitudes varied with strain and temperature. The z-values of lawn cultures were significantly lower than those of broth cultures (P < 0.05), but there were few differences between high-aw and reduced-aw samples. There were no significant differences of z-values based on strain type. These results highlight that thermal resistance can be affected by culture preparation and that osmolyte-induced changes to aw influence thermal inactivation of STEC by varying magnitudes. These results emphasize the challenges of extrapolating results from laboratory inactivation kinetic experiments to determine the inactivation of low-aw foods, especially those considered dry in nature. HIGHLIGHTS
Collapse
Affiliation(s)
- Jennifer C Acuff
- Department of Food Science and Technology, Virginia Tech, 1230 Washington Street, Blacksburg, Virginia 24061, USA
| | - Kim Waterman
- Department of Food Science and Technology, Virginia Tech, 1230 Washington Street, Blacksburg, Virginia 24061, USA
| | - Jahnavi Ramakrishnan
- Department of Food Science and Technology, Virginia Tech, 1230 Washington Street, Blacksburg, Virginia 24061, USA
| | - Monica A Ponder
- Department of Food Science and Technology, Virginia Tech, 1230 Washington Street, Blacksburg, Virginia 24061, USA.,(ORCID: https://orcid.org/0000-0001-7047-3127 [M.A.P.])
| |
Collapse
|
4
|
Howard-Varona C, Vik DR, Solonenko NE, Gazitua MC, Hobbs Z, Honaker RW, Kinkhabwala AA, Sullivan MB. Whole-Genome Sequences of Phages p000v and p000y, Which Infect the Bacterial Pathogen Shiga-Toxigenic Escherichia coli. Microbiol Resour Announc 2018; 7:e01400-18. [PMID: 30533810 PMCID: PMC6256609 DOI: 10.1128/mra.01400-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 10/22/2018] [Indexed: 01/17/2023] Open
Abstract
We report here the genome sequences and morphological characterizations of phages p000v and p000y, which infect the bacterial pathogen Shiga-toxigenic Escherichia coli O157:H7 and which are potential candidates for phage therapy against such pathogens.
Collapse
Affiliation(s)
| | - Dean R. Vik
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | | | | | - Zack Hobbs
- EpiBiome, Inc., Union City, California, USA
| | | | | | - Matthew B. Sullivan
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, Columbus, Ohio, USA
| |
Collapse
|
5
|
Hu S, Xiao X, Wu X, Xia X, Yu Y, Wu H. Comparative transcriptomic analysis by RNA-seq of Acid Tolerance Response (ATR) in EHEC O157:H7. Lebensm Wiss Technol 2017. [DOI: 10.1016/j.lwt.2017.01.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
6
|
Nirujogi RS, Muthusamy B, Kim MS, Sathe GJ, Lakshmi PTV, Kovbasnjuk ON, Prasad TSK, Wade M, Jabbour RE. Secretome analysis of diarrhea-inducing strains of Escherichia coli. Proteomics 2017; 17. [PMID: 28070933 DOI: 10.1002/pmic.201600299] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 12/19/2016] [Accepted: 01/05/2017] [Indexed: 01/05/2023]
Abstract
Secreted proteins constitute a major part of virulence factors that are responsible for pathogenesis caused by Gram-negative bacteria. Enterohemorrhagic Escherichia coli, O157:H7, is the major pathogen often causing outbreaks. However, studies have reported that the significant outbreaks caused by non-O157:H7 E. coli strains, also known as "Big-Six" serogroup strains, are increasing. There is no systematic study describing differential secreted proteins from these non-O157:H7 E. coli strains. In this study, we carried out MS-based differential secretome analysis using tandem mass tags labeling strategy of non-O157:H7 E. coli strains, O103, O111, O121, O145, O26, and O45. We identified 1241 proteins, of which 565 proteins were predicted to be secreted. We also found that 68 proteins were enriched in type III secretion system and several of them were differentially expressed across the strains. Additionally, we identified several strain-specific secreted proteins that could be used for developing potential markers for the identification and strain-level differentiation. To our knowledge, this study is the first comparative proteomic study on secretome of E. coli Big-Six serogroup and the several of these strain-specific secreted proteins can be further studied to develop potential markers for identification and strain-level differentiation. Moreover, the results of this study can be utilized in several applications, including food safety, diagnostics of E. coli outbreaks, and detection and identification of bio threats in biodefense.
Collapse
Affiliation(s)
- Raja Sekhar Nirujogi
- Institute of Bioinformatics, International Technology Park, Bangalore, India.,Centre for Bioinformatics, Pondicherry University, Puducherry, India.,McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Min-Sik Kim
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Applied Chemistry, Kyung Hee University, Yongin, Gyeonggi, South Korea
| | - Gajanan J Sathe
- Institute of Bioinformatics, International Technology Park, Bangalore, India.,Manipal University, Madhav Nagar, Manipal, India
| | - P T V Lakshmi
- Centre for Bioinformatics, Pondicherry University, Puducherry, India
| | - Olga N Kovbasnjuk
- Division of Gastroenterology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - T S Keshava Prasad
- Institute of Bioinformatics, International Technology Park, Bangalore, India.,Centre for Bioinformatics, Pondicherry University, Puducherry, India.,Manipal University, Madhav Nagar, Manipal, India.,NIMHANS-IOB Proteomics and Bioinformatics Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neuro Sciences, Bangalore, India.,YU-IOB Center for Systems Biology and Molecular Medicine, Yenepoya University, Mangalore, India
| | - Mary Wade
- Research and Technology Directorate, US Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, MD, USA
| | - Rabih E Jabbour
- Research and Technology Directorate, US Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, MD, USA
| |
Collapse
|
7
|
Fayemi OE, Buys EM. Effect ofLactobacillus plantarumon the survival of acid-tolerant non-O157 Shiga toxin-producingE. coli(STEC) strains in fermented goat's milk. INT J DAIRY TECHNOL 2016. [DOI: 10.1111/1471-0307.12340] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Olanrewaju E Fayemi
- Department of Food Science; University of Pretoria; Private Bag X 20 Hatfield 0028 Pretoria South Africa
| | - Elna M Buys
- Department of Food Science; University of Pretoria; Private Bag X 20 Hatfield 0028 Pretoria South Africa
| |
Collapse
|
8
|
Kim GH, Fratamico P, Breidt F, Oh DH. Survival and expression of acid resistance genes in Shiga toxin-producing Escherichia coli
acid adapted in pineapple juice and exposed to synthetic gastric fluid. J Appl Microbiol 2016; 121:1416-1426. [DOI: 10.1111/jam.13223] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 06/24/2016] [Accepted: 06/30/2016] [Indexed: 01/19/2023]
Affiliation(s)
- G.-H. Kim
- Department of Food Science and Biotechnology; Kangwon National University; Chuncheon Gangwon South Korea
- USDA-ARS Eastern Regional Research Center; Wyndmoor PA USA
| | - P. Fratamico
- USDA-ARS Eastern Regional Research Center; Wyndmoor PA USA
| | - F. Breidt
- USDA-ARS Food Science Research Unit; Department of Food; Bioprocessing and Nutrition Sciences; North Carolina State University; Raleigh NC USA
| | - D.-H. Oh
- Department of Food Science and Biotechnology; Kangwon National University; Chuncheon Gangwon South Korea
| |
Collapse
|
9
|
Hatab S, Athanasio R, Holley R, Rodas-Gonzalez A, Narvaez-Bravo C. Survival and Reduction of Shiga Toxin-Producing Escherichia coli
in a Fresh Cold-Pressed Juice Treated with Antimicrobial Plant Extracts. J Food Sci 2016; 81:M1987-95. [DOI: 10.1111/1750-3841.13382] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 06/01/2016] [Accepted: 06/06/2016] [Indexed: 12/11/2022]
Affiliation(s)
- Shaimaa Hatab
- College of Environmental Agricultural Sciences; Suez Canal Univ; Al-Arish, North Sinai 45516 Egypt
- College of Food Science and Pharmaceutics; Zhejiang Ocean Univ; Zhoushan 316022 China
| | - Renata Athanasio
- Food Science Dept; Univ. of Manitoba; Winnipeg MB R3T 2N2 Canada
| | - Richard Holley
- Food Science Dept; Univ. of Manitoba; Winnipeg MB R3T 2N2 Canada
| | | | | |
Collapse
|
10
|
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: 121] [Impact Index Per Article: 15.1] [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.
Collapse
|
11
|
Mei GY, Tang J, Carey C, Bach S, Kostrzynska M. The effect of oxidative stress on gene expression of Shiga toxin-producing Escherichia coli (STEC) O157:H7 and non-O157 serotypes. Int J Food Microbiol 2015; 215:7-15. [DOI: 10.1016/j.ijfoodmicro.2015.07.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 07/22/2015] [Accepted: 07/24/2015] [Indexed: 01/05/2023]
|
12
|
Verhaegen B, De Reu K, Heyndrickx M, Van Damme I, De Zutter L. Growth of Stressed Strains of Four Non-O157 Shiga Toxin-Producing Escherichia coli Serogroups in Five Enrichment Broths. J Food Prot 2015; 78:1960-6. [PMID: 26555518 DOI: 10.4315/0362-028x.jfp-15-019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The purpose of this study was to evaluate (i) the behavior of several strains of non-O157 Shiga toxin-producing Escherichia coli (STEC) serogroups (O26, O103, O111, and O145) exposed to different stress conditions and (ii) the growth dynamics of stressed and nonstressed non-O157 STEC cells in five enrichment media. STEC strains were exposed to acid, cold, and freeze stresses. Lethal and sublethal injuries were determined by plating in parallel on selective and nonselective agar media. Freeze stress (8 days, 20°C) caused the most lethal (95.3% ± 2.5%) injury, as well as the most sublethal (89.1% ± 8.8%) injury in the surviving population. Growth of stressed and nonstressed pure cultures of non-O157 STEC on modified tryptic soy broth, buffered peptone water (BPW), BPW with sodium pyruvate, Brila, and STEC enrichment broth (SEB) was determined using total viable counts. To compare growth capacities, growth after 7 and 24 h of enrichment was measured; lag phases and maximum growth rates were also calculated. In general, growth on BPW resulted in a short lag phase followed by a high maximum growth rate during the enrichment of all tested strains when using all three stress types. Furthermore, BPW ensured the highest STEC count after 7 h of growth. Supplementing the medium with sodium pyruvate did not improve the growth dynamics. The two selective media, Brila and SEB, were less efficient than BPW, but Brila's enrichment performance was remarkably better than that of SEB. This study shows that irrespective of the effect of background flora, BPW is still recommended for resuscitation of non-O157 STEC.
Collapse
Affiliation(s)
- Bavo Verhaegen
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium; Institute for Agricultural and Fisheries Research (ILVO), Technology and Science Food Unit, Brusselsesteenweg 370, 9090 Melle, Belgium
| | - Koen De Reu
- Institute for Agricultural and Fisheries Research (ILVO), Technology and Science Food Unit, Brusselsesteenweg 370, 9090 Melle, Belgium.
| | - Marc Heyndrickx
- Institute for Agricultural and Fisheries Research (ILVO), Technology and Science Food Unit, Brusselsesteenweg 370, 9090 Melle, Belgium. Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Inge Van Damme
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Lieven De Zutter
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
| |
Collapse
|
13
|
Iversen H, Lindbäck T, L’Abée-Lund TM, Roos N, Aspholm M, Stenfors Arnesen L. The gut bacterium Bacteroides thetaiotaomicron influences the virulence potential of the enterohemorrhagic Escherichia coli O103:H25. PLoS One 2015; 10:e0118140. [PMID: 25719195 PMCID: PMC4342160 DOI: 10.1371/journal.pone.0118140] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 12/17/2014] [Indexed: 11/18/2022] Open
Abstract
Enterohemorrhagic E. coli (EHEC) is associated with severe gastrointestinal disease. Upon entering the gastrointestinal tract, EHEC is exposed to a fluctuating environment and a myriad of other bacterial species. To establish an infection, EHEC strains have to modulate their gene expression according to the GI tract environment. In order to explore the interspecies interactions between EHEC and an human intestinal commensal, the global gene expression profile was determined of EHEC O103:H25 (EHEC NIPH-11060424) co-cultured with B. thetaiotaomicron (CCUG 10774) or grown in the presence of spent medium from B. thetaiotaomicron. Microarray analysis revealed that approximately 1% of the EHEC NIPH-11060424 genes were significantly up-regulated both in co-culture (30 genes) and in the presence of spent medium (44 genes), and that the affected genes differed between the two conditions. In co-culture, genes encoding structural components of the type three secretion system were among the most affected genes with an almost 4-fold up-regulation, while the most affected genes in spent medium were involved in chemotaxis and were more than 3-fold up-regulated. The operons for type three secretion system (TTSS) are located on the Locus of enterocyte effacement (LEE) pathogenicity island, and qPCR showed that genes of all five operons (LEE1-LEE5) were up-regulated. Moreover, an increased adherence to HeLa cells was observed in EHEC NIPH-11060424 exposed to B. thetaiotaomicron. Expression of stx2 genes, encoding the main virulence factor of EHEC, was down-regulated in both conditions (co-culture/spent medium). These results show that expression of EHEC genes involved in colonization and virulence is modulated in response to direct interspecies contact between cells, or to diffusible factors released from B. thetaiotaomicron. Such interspecies interactions could allow the pathogen to recognize its predilection site and modulate its behaviour accordingly, thus increasing the efficiency of colonization of the colon mucosa, facilitating its persistence and increasing its virulence potential.
Collapse
Affiliation(s)
- Hildegunn Iversen
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Toril Lindbäck
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Trine M. L’Abée-Lund
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Norbert Roos
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Marina Aspholm
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Lotte Stenfors Arnesen
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
- * E-mail:
| |
Collapse
|
14
|
Liu Y, Gill A, McMullen L, Gänzle MG. Variation in heat and pressure resistance of verotoxigenic and nontoxigenic Escherichia coli. J Food Prot 2015; 78:111-20. [PMID: 25581185 DOI: 10.4315/0362-028x.jfp-14-267] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study evaluated the heat and pressure resistance of 112 strains of Escherichia coli, including 102 strains of verotoxigenic E. coli (VTEC) representing 23 serotypes and four phylogenetic groups. In an initial screening, the heat and pressure resistance of 100 strains, including 94 VTEC strains, were tested in phosphate-buffered saline (PBS). Treatment at 60°C for 5 min reduced cell counts by 2.0 to 5.5 log CFU/ml; treatment at 600 MPa for 3 min at 25°C reduced the cell counts by 1.1 to 5.5 log CFU/ml. Heat or pressure resistance did not correlate to the phylogenetic group or the serotype. A smaller group of E. coli strains was evaluated for heat and pressure resistance in Luria-Bertani (LB) broth. Generally, the levels of heat resistance of E. coli strains in LB and PBS were similar; however, the levels of pressure resistance observed for treatments in LB broth or PBS were variable. The cell counts of pressure-resistant strains of VTEC were reduced by less than 1.5 log CFU/ml after treatment at 600 MPa for 3 min. E. coli strains were also treated with 600 MPa for 3 min in ground beef or inoculated into beef patties and grilled to 63 or 71°C. The cell counts of the VTEC E. coli O26:H11 strain 05-6544 were reduced by 2 log CFU/g by pressure treatment in ground beef. The cell counts of the heat-resistant E. coli strain AW1.7 were reduced by 1.4 and 3.4 log CFU/g in beef patties grilled to internal temperatures of 63 and 71°C, respectively. The cell counts of E. coli 05-6544 were reduced by less than 3 and 6 log CFU/g in beef patties grilled to internal temperatures of 63 and 71°C, respectively. To study whether the composition of the beef patties influenced heat resistance, E. coli strains AW1.7, AW1.7 Δ pHR1, MG1655, and LMM1030 were mixed into beef patties containing 15 or 35% fat and 0 or 2% NaCl, and the patties were grilled to an internal temperature of 63°C. The highest heat resistance of E. coli was observed in patties containing 15% fat and 2% NaCl.
Collapse
Affiliation(s)
- Yang Liu
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Canada
| | - Alex Gill
- Health Canada/Sante Canada, Microbiology Research Division, Bureau of Microbial Hazards, Ottawa, Canada
| | - Lynn McMullen
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Canada
| | - Michael G Gänzle
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Canada; School of Food and Pharmaceutical Engineering, Hubei University of Technology, Wuhan, People's Republic of China.
| |
Collapse
|
15
|
Consumer preferences, internal color and reduction of shigatoxigenic Escherichia coli in cooked hamburgers. Meat Sci 2014; 96:695-703. [DOI: 10.1016/j.meatsci.2013.09.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 09/04/2013] [Accepted: 09/07/2013] [Indexed: 01/08/2023]
|
16
|
Abstract
In the United States, it is estimated that non-O157 Shiga toxin-producing Escherichia coli (STEC) cause more illnesses than STEC O157:H7, and the majority of cases of non-O157 STEC infections are due to serogroups O26, O45, O103, O111, O121, and O145, referred to as the top six non-O157 STEC. The diseases caused by non-O157 STEC are generally milder than those induced by O157 STEC; nonetheless, non-O157 STEC strains have also been associated with serious illnesses such as hemorrhagic colitis and hemolytic uremic syndrome, as well as death. Ruminants, particularly cattle, are reservoirs for both O157 and non-O157 STEC, which are transmitted to humans by person-to-person or animal contact and by ingestion of food or water contaminated with animal feces. Improved strategies to control STEC colonization and shedding in cattle and contamination of meat and produce are needed. In general, non-O157 STEC respond to stresses such as acid, heat, and other stresses induced during food preparation similar to O157 STEC. Similar to O157:H7, the top six non-O157 STEC are classified as adulterants in beef by the USDA Food Safety and Inspection Service, and regulatory testing for these pathogens began in June 2012. Due to the genetic and phenotypic variability of non-O157 STEC strains, the development of accurate and reliable methods for detection and isolation of these pathogens has been challenging. Since the non-O157 STEC are responsible for a large portion of STEC-related illnesses, more extensive studies on their physiology, genetics, pathogenicity, and evolution are needed in order to develop more effective control strategies.
Collapse
Affiliation(s)
- James L Smith
- USDA, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania, USA
| | - Pina M Fratamico
- USDA, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania, USA.
| | - Nereus W Gunther
- USDA, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania, USA
| |
Collapse
|
17
|
Abstract
This article presents information related to emerging pathogens that are foodborne or have the potential to be foodborne including bacteria, viruses, and parasites. The phenotypic characteristics of these pathogens, their epidemiology, prevalence in foods, and transmission routes to humans as well as means for their control are also discussed.
Collapse
|