Effect of dairy probiotic combinations on in vitro gastrointestinal tolerance, intestinal epithelial cell adhesion and cytokine secretion

Gastrointestinal tolerance, adhesion to intestinal epithelium and immunomodulation are critical factors in maintaining probiotic efficacy. Seven different types of fermented milk were made from goat's milk using various culture compositions of three probiotics: Lactobacillus acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12 and Propionibacterium jensenii 702 and in vitro gastrointestinal tolerance, adhesion ability and stimulation of cytokine production by probiotics were evaluated. All probiotics and combinations demonstrated significantly lower viability after exposure to simulated gastric (pH 2.0) and intestinal (with 0.3% bile, pH 8.0) fluids (p < 0.05). The ability of probiotics to adhere to Caco-2 cells appeared to be influenced by the specific probiotic strains with which they were combined in the manufacturing of fermented milk. Only monocultures of lactobacilli and bifidobacteria and their co-cultures were able to induce low levels of IL-6 and TNF-α production from Caco-2 cells. It seems likely that co-cultures of various probiotics may affect their functional properties.