Probabilistic evaluation of Clostridium perfringens potential growth in order to validate a cooling process of cooked dishes in catering

The cook-chill operation, a widely used process within central cooking facilities, implies that cooked dishes have to be quickly cooled down immediately after cooking in order to prevent any food-borne diseases due to Clostridium perfringens. The food service operators are obliged to validate the efficiency of the cooling process in the context of their HACCP plan. To perform this cooling process, they can either ensure compliance with some reference criterion (maximal cooling duration) or demonstrate that the cooling operation is safe by carrying out prior tests. ocument presents an experimental method to validate the sanitary efficiency of the cooling process. In the studied kitchen the food was cooked and, successively, distributed into plastic containers, cooled down in blast-chiller and then stored in cold room. sts consisted in monitoring food temperature at the center of the containers from the end of cooking until the beginning of cold room storage. The measurements were performed during 6 cycles of food preparation. he monitored time–temperature profiles, thermal cooling equations were established for modeling. arameter of these thermal equations was linked with a distribution fitted with the experimental data. Then these thermal equations were coupled with predictive microbiology equations. A probabilistic calculation of the C. perfringens potential growth was carried out by using @Risk software. The proposed method required only simple monitoring equipments and could be easily implemented in central kitchens under the usual working conditions. oling conditions in the studied kitchen could be considered as satisfactory because the calculations give only a 0.4% probability that the C. perfringens potential growth was equal or greater than 1 log10 cfu/g.