Functional properties of the probiotic strain Bifidobacterium animalis subsp. lactis BB-12 in processed cereal/rice based product

The aim of this research is functional characterisation of processed cereal/rice based product enriched with a lyophilized probiotic culture of Bifidobacterium animalis subsp. lactis BB-12, intended to be developed as probiotic baby food. The results show that the bacterial counts determined for B. animalis subsp. lactis BB-12, expressed as log CFU/g of product, were maintained above 106 CFU/g during storage period, what is the level requested for probiotic products. In order to properly identify B. animalis subsp. lactis BB-12 after implementation in processed cereal/rice based product, phenotypic and genotypic characterisations were performed. Analysis of sugar fermentation profiles and SDS-PAGE analysis of soluble cell proteins, together with PCR with specific primers for Bifidobacterium spp. and AFLP DNA fingerprints confirmed the presence of B. animalis subsp. lactis BB-12 in final product. Introduction of the probiotic strains underscores a need to exclude the presence of antibiotic resistance determinants. Analysis of B. animalis subsp. lactis BB-12 susceptibility to the representatives of all major antibiotic groups revealed that the strain was sensitive to the most antibiotic tested, but to gentamycin, neomycin and streptomycin what is related to aminoglycoside antibiotic instability in acid conditions. Further important functional characteristics, survival in simulated gastrointestinal tract conditions and competitive pathogen exclusion by B. animalis subsp. lactis BB-12 implemented in processed cereal/rice based product were evaluated. Comparison of the viable cells count determined for the B. animalis subsp. lactis BB-12 lyophilised culture and in processed cereal/rice based product, respectively revealed much higher viable cell counts when probiotic culture B. animalis subsp. lactis BB-12 was applied in combination with processed cereal/rice based product supporting the protective effect of the food matrix. In addition, antimicrobial activity of B. animalis subsp. lactis BB-12 against test microorganism Salmonella enterica serovar Typhimurium FP1 was assayed. According to obtained results B. animalis subsp. lactis BB-12 inhibits Salmonella enterica serovar Typhimurium FP1 growth. In conclusion, overall results of this research proved that processed cereal/rice based product positively influenced the functionality of B. animalis subsp. lactis BB-12.