88D-14 |
Characterization of bacteriocin-producing lactic acid bacteria isolated from meat and meat products |
R. BROMBERG1, I. Moreno1, C. L. Zaganini, R. R. Delboni, V. N. Moreira, J. Oliveira, and A. L. S. Lerayer. (1) Institute of Food Technology, Avenida Brasil 2880, Campinas, 13073-001, Brazil The consumer demand for less preserved foods and the use of natural conservant agents to inhibit the pathogens and deteriorants growth leads the development of new hurdles. In meat, lactic acid bacteria are part of the microflora. The growth of lactic acid bacteria can cause microbial interference to spoilage and pathogenic bacteria through several mechanisms, such as bacteriocins. The purpose of this study was to isolate bacteriocin-producing lactic acid bacteria from various Brazilian meat and meat products. One hundred and forty five samples of raw meat and products were analyzed. Serial dilutions of the samples were made in 0.1% peptone, spread onto de Man Rogosa & Sharpe Agar (MRS) supplemented with 2% sodium glycerophosphate, 0.01% sodium azid and catalase (100 U final concentration), to minimize the effect of other interfering inhibitor lactic acid or hydrogen peroxide. The plates were overlaid with the same media to exclude inhibition due to lytic bacteriophage and incubated at 35°C for 48 hours until growth was evident. The back surface of the plates was overlaid with 4.5 ml of Triptone Soya Broth soft agar containing 500 ml of Staphylococcus aureus or Listeria innocua at a level of 106 to 107 organisms and the plates were incubated at 35°C for 24 hours. Colonies showing inhibition zones were picked and streaked onto MRS agar plates. The bacteriocin production by strains isolated was confirmed by well diffusion assay according to Tagg & Mc Given (1971). From 145 samples analysed 59 (40.7%) presented colonies with inhibition zones. Eight two strains of bacteriocin-producing lactic acid bacteria were isolated and characterized by Gram staining and catalase test. The antimicrobial activity of the bacteriocins produced by the acid lactic bacteria isolated in this research could work as a barrier to inhibit foodborne pathogens presented in foods.
Session 88D, Food Microbiology: General
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