Schilling, M. Wes
Date of Degree
Graduate Thesis - Open Access
Master of Science
College of Agriculture and Life Sciences
Department of Food Science, Nutrition and Health Promotion
Acid-stress adaptation in Listeria monocytogenes (Lm) serotype 4b and 1/2a occurred when cells were pre-exposed to pH 5.0 tryptic soy broth supplemented with yeast extract (TSB-YE) at 22°C or 37°C but not at 4°C. Prolonged time, varied sublethal acid pH, substitute of acidulants and addition of sodium chloride during 4°C mild acid pre-exposure still did not induce acid-stress adaptation in Lm. This finding was also validated using an acidic cheese, similar to what has seen for Gram-negative bacteria E. coli and Salmonella. Further investigation revealed that major cold shock protein in Lm CspL was not responsible for repressed acid-stress adaptation at 4°C. A bead beating treatment prior to mild acid pre-exposure at 4°C partially induced acid-stress adaptation after pre-exposure in 4°C to mild acid stress. Our data suggests that cold processing or cold storage temperature can lower the possibility of activating acid-stress adaptation in Lm.
Shen, Qian, "Influence of Temperature on Acid-Stress Adaptation in Listeria Monocytogenes" (2013). Theses and Dissertations MSU. 2719.