Incorporation of probiotic bacteria into a Swiss cheese slurry model system

The use of probiotic bacteria for health benefits has been studied for many years. Clinical studies have proven the effectiveness of probiotic bacteria, through regular consumption, in reducing some symptoms with disorders related to the gastrointestinal system. Gradient plating allowed for distinguishing probiotic bacteria from the Swiss cheese background micro flora using streptomycin in MRS agar. A final concentration of 1500 [Mu]g/mL Streptomycin inhibited the background micro flora but not the probiotic bacteria. With the use of rapid methods and a modified MRS agar, the incorporation of probiotic bacteria could be replicated in a short period. Bifidobacterium breve, B. infantis, B. longum and Pediococcus acidilactici were inoculated into the Swiss cheese slurry with a final cell count of 8 log10 cfu/g. No significant difference was seen in viability of the bacteria treatments or the ripening periods of 0, 7 and 10 d. The Swiss cheese background micro flora in the presence of each individual probiotic remained viable during the 10-d ripening period. No significant differences were seen for the viability of the background micro flora of Swiss cheese in the presence of probiotic bacteria based on bacterial treatment and ripening time. The Swiss cheese background micro flora in the presence of each probiotic bacteria was comparable with the control. The addition of Bifidobacterium breve, B. infantis, B. longum and Pediococcus acidilactici were examined for effects on the flavor characteristics, free amino acids, titratable acidity (TA) and pH were determined using a cheese slurry model system. Ripening time but not bacterial treatment had a significant effect for all analyses except for free amino acids. The detection of free amino acids was an indication of proteolytic activity in the slurry samples. Bifidobacteria samples showed increased amounts free amino acids when compared with the control and P. acidilactici samples. Titratable acidity and pH showed little difference between bacterial treatments of slurry samples. The results of this study show that probiotic bacteria were viable in the Swiss cheese curd slurry without adversely affecting the background micro flora and the addition of Bifidobacterium spp. or P. acidilactici did not significantly alter the flavor profile of a Swiss cheese slurry model system