Effect of cooling rate on Clostridium perfringens survival trends in selected home-made cooked, reheated, and recooled meals with different consumer scenarios

Food poisoning may occur due to enterotoxins produced by Clostridium perfringens in meal if the number of C. perfringens increases more than 1 log₁₀ cfu/g after cooking. Therefore, cooling step is important to control C. perfringens growth. The aim of this study was investigating the effect of cooling rate in home-made cooked and reheated/recooled meals on the growth of C. perfringens. Two different household type refrigerators and room temperature were adjusted as cooling environments. Cooling condition 1 (CC1, 15.5°C/hr), cooling condition 2 (CC2, 7.7°C/hr) and room temperature (RT, 6.2°C/hr) cooling rates were used. Three different meals which provide suitable medium for C. perfringens growth were prepared. The number of C. perfringens in meals that were cooled from 60 to 15°C at RT was higher than meals which were cooled at CC1 and CC2. There was no considerable difference on C. perfringens growth between the meals cooled at CC1 and CC2. Novelty impact statement: Clostridium perfringens causes foodborne diseases by improper cooling of hot foods and toxin production occurs with the increase in the number of C. perfringens. C. perfringens vegetative cell counts in 3 different meals were analyzed. It was observed that cooling meals from 60 to 15°C in room temperature increased the number of C. perfringens in meals, and C. perfringens proliferation can easily be seen during cooling rates slower than 7.7°C/hr.