Screening for the bacteriocin production of strains of lactic acid bacteria from various meat and meat products resulted in the detection of a bacteriocin-producing Lactococcus lactis ssp. hordniae CTC 484, isolated from chicken. The bacteriocin inhibited not only closely related lactic acid bacterium (Lactobacillus helveticus), but also pathogenic microorganisms (Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Clostridium perfringens, and Enterococcus faecalis). This compound was inactivated by alpha-chymotrypsin, trypsin, pronase E, ficin, pepsin, papain, and also by lipase. It was heat stable even at autoclaving temperature (121°C/10 min) and was produced under refrigerated storage. It was also active over a wide range of pH values (2-10), although the highest activity was observed in the lower pH range. The effectiveness of strain CTC 484 as well as that of its bacteriocin in reducing population levels and growth of Listeria monocytogenes in sterile beef were studied. The results indicated that the inoculation of this bacteria into the meat contributed to the safety improvement and the shelf life extension of this food.
lactic acid bacteria; biopreservation; characterisation; food; pathogenic bacteria
