Sporulation temperature and heat resistance of Bacillus spores:: A review

Sporulation temperature is one of the most important factors that determine the heat resistance of spores. Bacterial spores are usually more heat resistant when they are formed at higher temperatures. Sporulation temperature also influences the effect of pH of heating menstruum and the effect of different acids on spore heat resistance. Heat resistance is maximum at neutral pH and decreases with acidification, but when spores are sporulated at high temperatures the effect of acidic pH on heat resistance is lower at high heat treatment temperatures. Lactic and acetic acid decrease spore heat resistance more than other acidulants, but only when spores had been sporulated at high temperatures. These effects should be considered by canning factories of acid/acidified foods, especially in hot climate areas, where these high temperatures can be easily reached. The level of mineralization of spores obtained at different sporulation temperatures seems to be the most important mechanism responsible for their heat resistance.