D VALUES OF ESCHERICHIA COLI IN TILAPIA MEAT KRISTINE P. SEVILLA and ALONZO A. GABRIEL 1 Department of Food Science and Nutrition College of Home Economics University of the Philippines Diliman, Quezon City, Philippines Accepted for Publication February 29, 2008 ABSTRACT In this study, the decimal reduction times (D values) of the reference strain Escherichia coli (ATCC 25922) were established in tilapia (Oreochro- mis niloticus) meat homogenate. Known numbers of cells were inoculated to irradiated meat homogenate prior to heat treatments at 65, 70 and 75C. In all heating temperatures, inactivation rates significantly increased with increas- ing exposure times. The D values calculated from the E. coli survivor curves ranged from 0.50 to 1.13 min. The thermal resistance constant (Z value) calculated from the established D values was 28.5C. The established D and Z values of the reference strain may be used in calculating adequate thermal process schedules for tilapia meat, and possibly, other similar products. PRACTICAL APPLICATIONS This study established the heat resistance characteristics of the bacterium Escherichia coli (ATCC 25922) in a tilapia meat medium. The results of this study may be applied in food manufacturing and food service industries where tilapia meat is used as a raw material or an ingredient. The thermal resistance parameters determined in this study can be used in establishing adequate thermal process or cooking schedules to ensure the inactivation of the target microorganism. INTRODUCTION In the Philippines, seafood consumption is at a rate of 99 g per capita per day (Food and Nutrition Research Institute; FNRI 2001) and accounts for 1 Corresponding author. A.A. Gabriel, Alonso Hall, Regidor Street, University of the Philippines, Diliman Campus, 1101 Quezon City, Philippines. TEL: +632-9818500-loc. 3407; FAX: (+632) 9202091, (+632) 9273828; EMAIL: alonzo.gabriel@gmail.com Journal of Muscle Foods 21 (2010) 167–176. © 2010, The Author(s) Journal compilation © 2010, Wiley Periodicals, Inc. 167