29G-32 |
Kinetic analysis of growth of Clostridium perfringens in cooked beef under isothermal and dynamic conditions |
L. HUANG, Food Safety Intervention Technologies Research Unit, USDA-ARS-Eastern Regional Research Center, 600 E. Mermaid Ln., Wyndmoor, PA 19038-8598 Clostridium perfringens is a major foodborne pathogen affecting the safety of many cooked products regulated by USDA. This organism can grow rapidly at suitable temperatures. It is necessary to estimate the growth of this organism when process deviation and temperature abuse occurs. The objective of this research was to develop a new methodology to study the growth kinetics of this organism under isothermal and dynamic temperature conditions. Ground beef, inoculated with C. perfringens at approximately 100 spores per gram in vacuum-sealed plastic bags, was incubated isothermally and dynamically at temperatures 10-50oC. The growth data were collected and analyzed with a new kinetic method involving two differential growth equations. Four different temperature profiles, including 2 square-waves, linear cooling, and exponential cooling, were used to validate the models under dynamic conditions. Experimental and analytical results showed that the new differential equations could accurately describe the growth behavior of this organism under both isothermal and dynamic conditions. The errors were generally less than 0.5 log(CFU/g). The methodology developed in this study can be a new approach to predict and estimate the bacterial growth in cooked meat products that have undergone temperature abuse.
Session 29G, Food Microbiology: General
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