Behavior of different Bacillus strains with claimed probiotic properties throughout processed cheese (requeijao cremoso) manufacturing and storage

Even though spore-forming bacteria have been mainly linked to spoilage or foodborne pathogens vehiculated through foods, some strains of Bacillus can potentially present probiotic properties. The advantage of incorporating probiotic Bacillus strains in foods relies mainly on the fact that these microorganisms present high resistance to harsh processing conditions. Requeijao cremoso is a type of processed cheese highly appreciated in Brazil. During processing, this product is submitted to several harsh conditions (heating at 90 degrees C, for instance), leading to the inactivation of probiotic bacteria belonging to Lactobacillus and Bifidobacterium genera. That fact has precluded the development of probiotic requeijao cremoso products; however, probiotic Bacillus strains may comprise a promising alternative to overcome the low resistance of traditional probiotics to food processing. The objective of this study was to evaluate the behavior of different Bacillus strains with claimed probiotic properties throughout processed cheese (requeijao cremoso) manufacturing. A total of five different Bacillus strains with claimed probiotic properties (B. coagulans MTCC 5856, B. coagulans GBI-30 6086, B. subtilis PXN 21, B. subtilis PB6, and B. flexus HK1) were individually inoculated at different stages of manufacture - curd pasteurization, coagulation, and fusion - of requeijao cremoso and their survival in each of these stages was determined. The survival of B. coagulans GBI-30 6086 was further assessed throughout requeijao cremoso production and shelf life (45 days at 6 degrees C). Besides, the chemical composition, level of proteolysis, and fatty acid profile of the treatments during shelf life were evaluated. The fusion stage was found as the most appropriate for the addition of B. coagulans GBI-30 6086, which allows the production of probiotic requeijao cremoso and facilitates the technological process while preventing the occurrence of final product recontamination.