Heat Resistance Analysis of Bacillus cereus Isolated from the Tomato Farm Environments

Abstract

Bacillus cereus (B. cereus) is a spore forming bacteria with a highly adhesive ability on the food surface and which expresses concern about commercial sterilization due to heat resistance. In this study, the heat challenge was performed at 60℃ for 60 min to derive the importance of the inactivation of bacteria by time during heating 14 isolates of B. cereus from the tomato farm environment. As a result, the final cell counts of B. cereus reduced after heating were -3.6 Log CFU/mL on average (minimum: -2.8 Log CFU/mL, maximum: -4.7 Log CFU/mL). Reduced cell counts of B. cereus after heating for 60 min ranged from 0.5 Log CFU/mL to 2.4 Log CFU/mL. Remained B. cereus after heating can recover in an appropriate environment, and cause foodborne illness. B. cereus existed in the farm environment during the cultivation stage of agricultural products can be transferred to agricultural products through various routes such as soil, toilet handles and worker gloves, thus, the management of B. cereus in a farm environment is essential. In addition, improper sterilization, manufacturing, processing and packaging in the food processing stage cannot be expected to inhibit the complete growth of foodborne pathogenic bacteria, and the risk of foodborne illness can be increased. Therefore, thorough management of these processes is considered important.