Production of anti-microbial substances by probiotics.

Bacterial antagonism has been recognised for over a century but in recent years this phenomenon has received more scientific attention, particularly in the use of various strains of lactic acid bacteria (LAB). Antimicrobial compounds produced by LAB have provided these organisms with a competitive advantage over other microorganisms. Lactic acid bacteria have a natural ecological niche in many foods as well as in the intestinal tract. The efficacy and spectrum of antimicrobial products of lactic acid bacteria are broad and include lactic and acetic acid, hydrogen peroxide, carbon dioxide, diacetyl as well as bacteriocins or bacteriocin-like substances. Further screening for agents with a broad spectrum of activity is required. This will involve genetic or protein engineering of such compounds to commercialise these agents.