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M. E. STILES, Dept. of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, AB T6G 2P5, Canada

Meat is highly perishable and it has been implicated in many outbreaks of bacterial foodborne illness. For many meats the surface is the main location of contaminating bacteria. The dominating bacteria are dramatically affected by the gas atmosphere around the meat. Under anaerobic conditions, lactic acid bacteria (LAB) dominate. The LAB exclude other bacteria by competitive exclusion, production of organic acids and/or other inhibitory compounds, such as antibacterial peptides (bacteriocins). LAB on the meat surface are an adventitious biofilm, but the opportunity exists to inoculate bacteriocinogenic LAB onto the meat surface and effect a predictable storage life and enhanced safety. This can be achieved with naturally occurring or genetically enhanced LAB. Naturally occurring strains have the disadvantage that their antibacterial spectrum is limited by the natural bacteriocins that they produce. Genetically enhanced LAB could produce an array of bacteriocins that are active against a broad spectrum of gram-positive bacteria and also could be modified to give activity against gram-negative bacteria, such as Escherichia coli and Salmonella.