29G-4 |
Cold shock response of Vibrio parahaemolyticus |
C. C. CHOU and C. Lin. Graduate Inst. of Food Science and Technology, National Taiwan University, 59, Lane 144, Sec. 4, Keelung Rd., Taipei, 106, Taiwan Vibrio parahaemolyticus is a foodborne pathogen. Illness resulting from the consumption of foods contaminated with V. parahaemolyticus has been reported all over the world, especially in Asian countries where people frequently consume seafood in their daily life. Low temperature preservation is used commonly in food processing to control growth and survival of spoilage-causing and pathogenic microorganisms. However, it is reported that microorganisms adapted to a period of low growth temperature (cold shock) may promote survival in similar or other adverse environments. This prompts the necessity to understand the cold shock response of V. parahaemolyticus. Our objective was to investigate the impact of cold shocking on the survival of V. parahaemolyticus subjected to subsequent low temperature and other adverse conditions. In this study, V. parahaemolyticus, a chop board isolate, was subjected to cold shock treatment at 20 or 15 ¢J for 2 or 4 h. The susceptibility of the cold-shocked V. parahaemolyticus subjected to subsequent low temperature (5, -18 ¢J ) and other adverse conditions (47 ¢J, 6 ppm crystal violet, 1000 ppm hydrogen peroxide, 8% ethanol, 25 mM lactic acid, 25 mM lactic acid) was investigated. Results obtained from the present study have showed that cold shock treatment under the conditions tested, in general, enabled V. parahaemolyticus cells to survive better in the subsequent challenge of low temperatures, crystal violet and ethanol, while became more susceptible to high temperature (47 ¢J), hydrogen peroxide and organic acids (lactic and acetic acid) than the non-shocked cells. Furthermore, the temperature and time of the cold shock treatment may affect the cold shock response of V. parahaemolyticus. These phenomena observed are of significant importance with regard to food safety. Since cooling regimes do exist in the food industry, which could potentially induce a cold shock phenomenon. Data obtained from the present study provide valuable information when more accurate risk assessments is to be made on food processing operation and thus to avoid the occurrence of food borne outbreak caused by V. parahaemolyticus.
Session 29G, Food Microbiology: General
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