Antibacterial, simulated digestive system tolerance and colon cancer cell lines adhesion properties of selected lactic acid bacteria of food origin

Abstract

Lactic acid bacteria (LAB) are widespread in nature and are one of the major microbial groups involved in the fermentation of different types of food. LAB possess a large number of metabolic properties that are responsible for the organoleptic characteristics of the final product including antioxidants, organic acids, antimicrobial compounds, modulating and improving microbial balance in the gut. Therefore, to determine the appropriate LAB for the development of functional food products, commercial LAB strain screening had been carried out. The antibacterial activity, tolerant to acids (pH 2, 3 and 4), bile salts (0.3%, 0.5% and 1.0%) and adhesion to colon cancer cell lines (HT29 and SW480) of several LABs (Lactobacillus paracasei UALpc-04™, Lactobacillus plantarum UALp-05™, Lactobacillus acidophilus DDS®-1, Bifidobacterium bifidum UABb-10™ and Streptococcus thermophilus UASt-09™) were performed. The studies indicated that Lb. plantarum UALp-05™ and B. bifidum UABb-10™ showed more than 106 CFU/mL viability when tested against acid and bile saline with higher adherence to cancer cell lines compared to other strains. The antibacterial activity showed that these two LAB strains also gave a higher inhibition zone of 13 to 17 mm against five strains of pathogens (Escherichia coli ATCC® 0157™, Salmonella enterica serovar Typhimurium ATCC® 53648™, Salmonella enterica serovar Enteritidis (MDC15), Streptococcus bovis ATCC® 9809™ and Listeria monocytogenes ATCC® 51772™). Our results indicated that Lb. plantarum UALp-05™ and B. bifidum UABb-10™ strains could be used as adjunct cultures for contributing to the health of gastrointestinal system and decreasing the risk factor of colon cancer.