APPLICATION OF LYSOSTAPHIN-PRODUCING LACTOBACILLI TO CONTROL STAPHYLOCOCCAL FOOD POISONING IN MEAT-PRODUCTS

The potential of lysostaphin-producing strains of Lactobacillus curvat us (Lys(+)) to prevent food-borne illness by Staphylococcus aureus was investigated under practical conditions. A response surface model was developed to estimate the effect of pH, temperature, and salt concent ration on the lysostaphin activity. The model was applied to fermentin g sausages, and a 90% reduction of lysostaphin activity at ripening wa s predicted. The residual activity was sufficiently high to reduce sta phylococcal counts by 10(4) to 10(5) CFU/g within 2 to 3 days to below the level of detection. These results were obtained in pilot scale ex periments with L. curvatus (Lys(+)) as a starter culture and S. aureus as well as Staphylococcus carnosus as model contaminants. The applica bility of L. curvatus (Lys(+)) as a protective culture was studied in a mayonnaise-based meat salad. Upon incubation at 25 degrees C the sta phylococci were rapidly killed within 24 h, whereas in the presence of the isogenic Lys(-) strain the staphylococci grew up to numbers of 10 (7) CFU/g.