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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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Spatial and space-time clustering and demographic characteristics of human nontyphoidal Salmonella infections with major serotypes in Toronto, Canada. PLoS One 2020; 15:e0235291. [PMID: 32609730 PMCID: PMC7329108 DOI: 10.1371/journal.pone.0235291] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/11/2020] [Indexed: 01/04/2023] Open
Abstract
Nontyphoidal Salmonella enterica (NTS) causes a substantial health burden to human populations in Canada and worldwide. Exposure sources and demographic factors vary by location and can therefore have a major impact on salmonellosis clustering. We evaluated major NTS serotypes: S. Enteritidis (n = 620), S. Typhimurium (n = 150), S. Thompson (n = 138), and S. Heidelberg (n = 136) reported in the city of Toronto, Canada, between January 1, 2015, and December 31, 2017. Cases were analyzed at the forward sortation area (FSA)—level (an area indicated by the first three characters of the postal code). Serotype-specific global and local clustering of infections were evaluated using the Moran's I method. Spatial and space-time clusters were investigated using Poisson and multinomial scan statistic models. Case-case analyses using a multinomial logistic regression model was conducted to compare seasonal and demographic factors among the different serotypes. High infection rate FSAs clustered in the central region of Toronto for S. Enteritidis, in the south-central region for S. Typhimurium, in north-west region for S. Thompson, and in the south-east region for S. Heidelberg. The relative risk ratio of S. Enteritidis infections was significantly higher in cases who reported travel outside of Ontario. The relative risk ratio of infections was significantly higher in summer for S. Typhimurium, and in fall for S. Thompson. The relative risk ratio of infection was highest for the 0–9 age group for S. Typhimurium, and the 20–39 age group for S. Heidelberg. Our study will aid public health stakeholders in designing serotype-specific geographically targeted disease prevention programs.
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