Investigation of the potential direct and cross protection effects of sublethal injured Salmonella Typhimurium induced by radio frequency heating stress

Shunshan Jiao; Hangjin Zhang; Meiji Liao; Zvi Hayouka; Pu Jing

doi:10.1016/j.foodres.2021.110789

Investigation of the potential direct and cross protection effects of sublethal injured Salmonella Typhimurium induced by radio frequency heating stress

Food Res Int. 2021 Dec;150(Pt A):110789. doi: 10.1016/j.foodres.2021.110789. Epub 2021 Oct 26.

Authors

Shunshan Jiao¹, Hangjin Zhang¹, Meiji Liao¹, Zvi Hayouka², Pu Jing³

Affiliations

¹ 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.
² Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
³ 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. Electronic address: pjing@sjtu.edu.cn.

PMID: 34865804
DOI: 10.1016/j.foodres.2021.110789

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 a_w ≥ 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.

Keywords: Cell morphology; Fatty acid; Low-moisture foods; Pasteurization; Water activity.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cross Protection*
Heating
Hot Temperature
Radio Waves / adverse effects
Salmonella typhimurium*