61C-12 |
Biochemical properties and microbial inhibition spectrum of a bacteriocin produced by Lactobacillus carnis |
H. MINOR-PÉREZ1, E. Ponce-Alquicira1, A. Farrés González Sarabia2, C. Regalado-González3, and I. Guerrero-Legarreta1. (1) Departamento de Biotecnología, Universidad Autónoma Metropolitana, Iztapalapa, Apartado Postal 55-535, Mexico D.F., 09340, Mexico, (2) Facultad de Química, Universidad Nacional Autónoma de México, Mexico D.F., Mexico, (3) Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, Mexico Among other metabolites produced by lactic acid bacteria, bacteriocins have been recently studied as meat preservatives. However, in order to apply them to food materials, it is necessary to explore several biochemical aspects that could affect their efficiency as biopreservatives. The objective of this work was to evaluate the microbial inhibition spectrum of a bacteriocin produced by Lactobacillus carnis, against several Listeria monocytogens strains. Adsorption pH and bacteriocin stability at various temperatures was also studied. L. carnis was isolated from pork and identified as a bacteriocin producing strain. The bacteriocin was produced in APT broth under 80:20 N2/CO2 atmosphere during 18 h at 37°C. The inhibition spectrum was evaluated against various L. monocytogens strains using the agar diffusion technique, where the target strain was Lactobacillus hilgardii NRRL B-1139. Thermal resistance was determined by heating the purified bacteriocin during 20 min at 40, 60, 80 and 100°C. Adsorption pH was also determined. The bacteriocin produced by L. carnis inhibited the growth of several L. monocytogens strains. The highest bacteriocin concentration was obtained by precipitation with 60 and 80% ammonium sulphate. Bacteriocin activity was gradually lost as the temperature was increased. At 80 and 100°C, 15 to 20% of the original activity was retained. At pH 6.0 to 6.5 the producing cell adsorbed the bacteriocin. This bacteriocin could be applied to meat and meat products to inhibit the growth of L. monocytogens. As it is heat stable, it can be used in mildly cooked products. According to its adsorption pH, it can be used in low acid food products.
Session 61C, Food Microbiology: General I
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