"Diversity and Characteristics of Heat-Stress Adaptation in Listeria Mo" by Priyanka Mahesh Jangam
 

Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Nannapaneni, Ramakrishna

Committee Member

Silva, Juan L.

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 (M.S.)

College

College of Agriculture and Life Sciences

Department

Department of Food Science, Nutrition and Health Promotion

Abstract

A set of 37 strains including 13 serotypes of Listeria monocytogenes (Lm) were analyzed for heat tolerance at 60°C for 10 min and further categorized into three groups; low (strains with <2 log survival), medium (2-4 log survival), and high (4-6 log survival) heat tolerant. When Lm strains representing each group were subjected to sub-lethal heatstress at 48°C prior to 60°C, the survivals of all strains were increased by at least 5 log CFU/ml when compared to controls. Sub-lethal heat-stress at 48°C for 30-60 min increased the heat-stress resistance of Lm strains by doubling D60°C values from 1.9-4.3 to 5.0-10.4 min. When Lm cells were cooled after sublethal heat-stress at 48°C prior to 60°C treatment, such acquired heat-stress adaptation was unstable at 22°C but was found to be highly stable for up to 24 h at 4°C. These results will have potential implications in food safety risk analysis for Lm.

URI

https://hdl.handle.net/11668/21097

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