Lactic acid bacteria: their applications in foods

Lactic acid bacteria (LAB) play an important role in food, agricultural, and clinical applications. The general description of the bacteria included in the group is gram-positive, nonsporing, nonrespiring cocci or rods, which produce lactic acid as the major end product during the fermentation of carbohydrates.1 The common agreement is that there is a core group consisting of four genera; Lactobacillus, Leuconostoc, Pediococcus and Streptococcus. Recent taxonomic revisions have proposed several new genera and the remaining group now comprises the following: Aerococcus, Alloiococcus, Carnobacterium, Dolosigranulum, Enterococcus, Globicatella, Lactococcus, Oenococcus, Tetragenococcus, Vagococcus, and Weissella.2 Their importance is associated mainly with their safe metabolic activity while growing in foods utilising available sugar for the production of organic acids and other metabolites. Their common occurrence in foods along with their longlived uses contributes to their natural acceptance as GRAS (Generally Recognised as Safe) for human consumption.3 The EFSA’s ‘Panel on Biological Hazards (BIOHAZ)’ has concluded that for the fermenting bacteria associated with food, whether resistant to antibiotics or not with the possible exception of enterococci there is no evidence for any clinical problem.4 However, they can act as a reservoir for transferable resistance genes. Strains with genes transferable in such a way could inter the food chain and increase the probability of a transfer to food associated intestinal pathogenic organisms.