Bacterial Spores in Food: Survival, Emergence, and Outgrowth

Spore-forming bacteria are ubiquitous in nature. The resistance properties of bacterial spores lie at the heart of their widespread occurrence in food ingredients and foods. The efficacy of inactivation by food-processing conditions is largely determined by the characteristics of the different types of spores, whereas food composition and storage conditions determine the eventual germination and outgrowth of surviving spores. Here, we review the current knowledge on variation in spore resistance, in germination, and in the outgrowth capacity of spores relevant to foods. This includes novel findings on key parameters in spore survival and outgrowth obtained by gene-trait matching approaches using genome-sequenced Bacillus spp. food isolates, which represent notorious food spoilage and pathogenic species. Additionally, the impact of strain diversity on heat inactivation of spores and the variability therein is discussed. Knowledge and quantification of factors that influence variability can be applied to improve predictive models, ultimately supporting effective control of spore-forming bacteria in foods.