Diversity and fate of spore forming bacteria in cocoa powder, milk powder, starch and sugar during processing: A review

Background: Raw materials such as cocoa, milk powder, sugar, and starch are widely used in the formulation of a wide variety of processed foods. The unit operations applied during their production vary according to their specific properties, technological advances and needs, which undoubtedly affect the microbial composition found in these raw materials. The microbial composition of these raw materials is known to consist mainly of spores of bacteria, which are known to withstand harsh food processing conditions. Scope and research: This article aims to discuss data available on the diversity of spore forming bacteria in selected raw materials (cocoa, milk powder, sugar, starch). These raw materials are contaminated mainly by spore forming bacteria, which can germinate and be a concern in products made with these ingredients. In addition, this review presents data gaps and studies needed to establish the fate of spore forming bacteria throughout the production chain of specific raw materials. Key findings and conclusions: The review of literature conducted in this study indicates that data on the effects of processing and diversity of spore forming bacteria in sugar and starch are much scarcer compared with cocoa and milk powders. Thus, cutting-edge approaches combining quantitative data with metagenomics could be used to improve our knowledge on the fate and diversity of spore forming bacteria in raw materials. These approaches can be employed to guide further developments that are aimed at enhancing food safety and controlling food spoilage caused by spore forming bacteria.