Evaluation of adaptive response in E. coli O157:H7 to UV light and gallic acid based antimicrobial treatments. (December 2019)

• Record Type: Journal Article
• Authors: Wang, Qingyang; Buchanan, Robert L.; Tikekar, Rohan V.
• Is Part Of: Food control. Volume 106(2019)
• Publication Date: 2019-12
• Subjects: Stress adaptive response -- Non-thermal technology -- Sub-lethal stress; Food -- Quality -- Periodicals; Food -- Analysis -- Periodicals; Food handling -- Periodicals; Food industry and trade -- Quality control -- Periodicals; Aliments -- Industrie et commerce -- Qualité -- Contrôle -- Périodiques; Aliments -- Qualité -- Périodiques; Aliments -- Analyse -- Périodiques; Hygiène alimentaire -- Périodiques; Food -- Analysis; Food handling; Food -- Quality; Periodicals; Electronic journals; 664.07
• DOI: 10.1016/j.foodcont.2019.106723
• Languages: English
• ISSNs: 0956-7135

Abstract

Abstract: Ability of bacteria to develop cross-protection to various stresses is well-known. However, exploration into cross-protection between conventional physiological stresses and emerging antimicrobial treatments is limited. Previously, we developed two new antimicrobial treatments based on a combined UV-A light and gallic acid (UVA + GA) treatment and enhanced antimicrobial action of gallic acid by UV-C exposure (UVC-GA) against Escherichia coli O157:H7. In this study, we investigated (a) whether prior exposure to sub-lethal stresses (heat, acid, osmotic and oxidation) can increase the resistance of E. coli O157:H7 towards these newly developed treatments, and (b) whether repeated exposure to these two treatments selects for E. coli O157:H7 sub-population resistant towards heat, acid, and oxidative challenge. Prior exposure to heat or acid stress increased (p < 0.05) the resistance of E. coli O157:H7 towards UVA + GA treatment, while osmotic stress increased (p < 0.05) their sensitivity to that treatment. Interestingly, only heat stress showed protective (p < 0.05) effect to subsequent UVC-GA treatment, while acid or osmotic stress increased (p < 0.05) the sensitivity. Prior exposure to oxidative stress had no effect (p > 0.05) on the sensitivity of the bacteria to either of the treatments. Repeated exposure to UVA + GA or UVC-GA treatment selected for a sub-population that demonstrated higher (p < 0.05) resistance towards these two treatments as well as heat or acid challenge. Further experiments showed that increased synthesis of enzymes such as superoxide dismutase and up-regulation of general stress response regulator were likely associated with the development of cross-protection. Thus, sub-lethal conditions encountered during food processing should be considered in the development and optimization of emerging non-thermal technologies. Highlights: Prior heat/acid stress increased bacterial resistance to UVA + GA/UVC-GA treatment. Repetitive exposure increased bacterial resistance to UVA + GA/UVC-GA treatment. Bacterial resistance to UVA + GA/UVC-GA treatment was reversible. UVA + GA/UVC-GA resistant cultures had higher resistance to heat or acid challenge. Stress proteins and general stress response regulator contributed to resistance.