Several mechanism and non-mechanism-based studies supporting the claim that lactic acid bacteria (LAB) strains confer health benefits and play immune-modulatory roles were examined in this review. Probiotic applications of LAB on global burdens such as obesity and type-2 diabetes were discussed as well as the use of yoghurt and ice cream as important vehicles to convey several beneficial LAB strains. Probiotic and symbiotic dairy products may be used in the nearest future to treat a variety of health disorders. Current studies suggest that lactic acid bacteria possess anti-obesity and anti-diabetic propensities on their hosts and thus can play a crucial role in human health care. Research in the rheological and physicochemical properties of ice cream as well as its applications are also on the increase. These applications face certain hurdles including technological (for less developed countries), consumer acceptability of new functional foods may be influenced by culture, ethics or religion. There is need for more studies on the genetic basis for probiotic properties which will give further understanding regarding novel manipulation skills and applicability in nutrition and health sectors. More studies confirming the direct effects of probiotic LABs in lowering the spread of food-borne and other pathogens are also anticipated.

Lactobacillus helveticus, an obligatory hetero-fermentative LAB, is Generally Recognized as Safe (GRAS) and is gaining popularity for application in dairy products. Lactic acid bacteria (LAB) play a remarkable role in inhibiting the growth of pathogenic bacteria in food products, without disturbing the sensory attributes of the food. In this study, the screening of the antimicrobial potential of Lactobacillus helveticus KLDS 1.8701 against four food-borne pathogens including Listeria monocytogenes ATCC 19115, Salmonella typhimurium ATCC 14028, Staphylococcus aureus ATCC 25923, and Escherichia coli O157:H7 ATCC 43889 in vitro was inspected using the Oxford cup method and mixed culture inhibition assays. The organic acid production and antimicrobial potential of the cell-free supernatants (CFS) have been evaluated via different treatments and analysis using high performance liquid chromatography (HPLC). The analysis results revealed that KLDS 1.8701 exhibited the highest antimicrobial potential compared to other antimicrobial strains. The antimicrobial activity of KLDS 1.8701 resulted from the organic acids in the culture and CFS. From the study, it was found that carbon sources, as well as organic acid production, accelerate the antimicrobial activity of KLDS 1.8701 and the fructooligosaccharides (FOS) were considered the best for improving the proliferation of KLDS 1.8701 and supporting its antimicrobial action. Results of the mixed culture inhibition assays showed that part of the antimicrobial activity resulted from the inhibitory action of the bacteria itself in culture, and this action required cellular contact between the food-borne pathogens and KLDS 1.8701. Conversely, the results of the antimicrobial spectrum assay revealed that some Lactobacilli remained unaffected by KLDS 1.8701. KLDS 1.8701 might also be favorable for use as a supplementary starter in fermented dairy productions. Furthermore, KLDS 1.8701 could survive well under GI tract conditions. Further studies on in vivo inhibition assays and the probiotic effects are recommended.

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This study investigated the effects of KLDS 1.8701 and AD1 administrations by gavage on intestinal microflora and mucosal immunity in diarrhea mice infected by Escherichia coli O157:H7 compared to normal mice. The levels of E. coli, Enterobacteria, and Enterococcus decreased significantly (P < 0.05), while viable counts of Lactobacilli and Bifidobacterium increased in diarrhea mice. Moreover, KLDS 1.8701 and AD1 improved secretion of secretory immunoglobulin A and enhanced the levels of interferon-γ and interleukin. Results indicate that KLDS 1.8701 and AD1 could effectively alleviate diarrhea in mice via modulation of intestinal microflora and improve the function of immune system. The study on the effect of KLDS1.8701 and AD1 supplementation in human flora-associated animal models was recommended.

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