THE POTENTIAL OF LACTIC-ACID BACTERIA FOR THE PRODUCTION OF SAFE AND WHOLESOME FOOD

By tradition lactic acid bacteria (LAB) are involved in the production of fermented foods. These constitute one quarter of our diet and are characterized by a safe history, certain beneficial health effects, and an extended shelf life when compared with raw materials. The various fermenting substrates are habitats for specific LAB that differ in their metabolic potential. The health effects exerted by LAB are the following: 1. Production of lactic acid and minor amounts of acetic and formic acid. These cause: a drop in pH and thereby growth inhibition of food spoiling or poisoning bacteria; killing of certain pathogens; detoxification by degradation of noxious compounds of plant origin (usually in combination with plant-derived enzymatic activities). 2. Production of antimicrobial compounds (e.g. bacteriocins, H2O2, fatty acids). 3. Probiotic effects as live organisms in food. The wholesomeness of LAB can also be extended to fields outside human nutrition, as they may act as probiotics in animal production or as plant protectives in agriculture and thus contribute to healthy raw materials for food production. Modem concepts or perspectives of the application of LAB include the following: 1 .Selection of the best adapted and safely performing LAB strains. 2. Selection of strains with probiotic effects. 3. Selection of strains with health-promoting effects (e.g. production of vitamins or essential amino acids, anti-tumour activity). 4. Selection of strains with food protective activities (inhibiting spoilage or food pathogens). These strains can be added to food or used as starters in food fermentations. They may be found as wild-type organisms or can be obtained by genetic engineering. Methods for modification of their genetic potential have been developed.