"Influence of Temperature on Acid-Stress Adaptation in Listeria Monocyt" by Qian Shen
 

Theses and Dissertations

Author

Qian Shen

Issuing Body

Mississippi State University

Advisor

Nannapaneni, Ramakrishna

Committee Member

Kim, Taejo

Committee Member

Schilling, M. Wes

Date of Degree

8-17-2013

Document Type

Graduate Thesis - Open Access

Major

Food Science and Technology

Degree Name

Master of Science

College

College of Agriculture and Life Sciences

Department

Department of Food Science, Nutrition and Health Promotion

Abstract

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.

URI

https://hdl.handle.net/11668/19874

Comments

cold stress||temperature||acid-stress adaptation||Listeria monocytogenes

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