Purpose: To evaluate the resistance of Bacillus probiotics in the different stages of the technological process of cream curd cheese manufacturing.
Methods: Probiotic Bacillus strains (Bacillus coagulans Lactospore; Bacillus coagulans GBI-30, 6086; Bacillus subtilis PB6; Bacillus subtilis PXN1; Bacillus flexus HK1) spores were added at different stages of cream curd cheese production process: prior to pasteurization, prior to coagulation, and prior to curd fusion. During all stages, samples were collected and spores were further enumerated using appropriate culture media and thermal shock, as indicated by suppliers of the strains. The number of survivors for each step studied was calculated based on initial inoculum level and spores recovered after each processing step.
Results: In the steps of pasteurization, coagulation and curd fusion, Bacillus coagulans GBI-30, 6086 showed better resistance in comparison to other strains tested (P < 0.05). However, at the step of curd coagulation, Bacillus coagulans Lactospore, Bacillus subtilis PB6 and, Bacillus flexus HK1, presented similar resistance to Bacillus coagulans GBI-30, 6086 (P > 0.05). At this step, Bacillus subtilis PXN1 strain was the least resistant. Thus, among the five strains analyzed, Bacillus coagulans GBI-30 consistently showed good resistance at all stages of the process.
Significance: In this study it has been found that probiotic Bacillus can be a very important option for delivering probiotics through foods processed under harsh conditions. Data indicates that the GRAS strain Bacillus coagulans GBI-30, 6086 seems to be the best option for delivering probiotics through CC.