The Growth Potential of Bacillus cereus in Ready-to-Reheat Vegetable Soups

Abstract

Bacillus cereus (hereafter, B. cereus) poisoning often arises from the consumption of Ready-To-Reheat vegetable soups in which an intensive growth of the vegetative cells of B. cereus take place. The market for these soups is increasing significantly worldwide. For the producer it is important to determine if soups can promote the growth of B. cereus, by calculating its growth potential. We can achieve this goal by carrying out an efficient challenge test. In our study we have designed and performed a challenge test in three batches of an emmer (Triticum monococcum) and vegetable soup that undergo a second pasteurization treatment after packaging. We found out that under refrigeration conditions B. cereus is unable to multiply in the soup, instead, under conditions of thermal abuse, B. cereus can grow during 90 days of shelf life with a growth potential of 0.82 logarithms. It is essential to keep the entire production phase under control using effective GMP (Good Manufacturing Practices) and GHP (Good Hygiene Practices) measures, to ensure that the freshly produced soups contain low loads of the spores of B. cereus. In this way, the vegetative cells born from the germination of the spores cannot reach the infectious dose necessary to induce the food poisoning.