Caracterização preliminar de bacteriocinas produzidas por seis cepas de bactérias láticas isoladas de produtos cárneos embalados a vácuo

Abstract

In this work, the bacteriocins produced by six bacterial strains were studied (Lactobacillus sake 1, Lactobacillus curvatus 5, Leuconostoc mesenteroides 11, Leuconostoc sp 12, Lactobacillus curvatus 14 and Lactobacillus sake 16). Title of inhibitory activity was determined by critical dilution assay, using Lactobacillus sake ATCC 15521 and Listeria monocytogenes as indicator microorganisms. The inhibitory compounds were also characterized with respect to stability to the action of enzymes, thermostability, stability in several pHs and mode of action (bactericide or bacteriostatic) towards Listeria monocytogenes. No bacteriocin was destroyed by pepsin, but all of them were destroyed by proteinase K, trypsin and a-amylase (except that a-amylase did not inactivate the bacteriocin produced by Leuconostoc sp 12). Lactobacillus sake 1, Leuconostoc mesenteroides 11 and Lactobacillus sake 16 exerted antilisterial activity. The more active strains against Listeria monocytogenes were Lactobacillus sake 1 and Leuconostoc mesenteroides 11 (12.800 AU/ml). Bacteriocins produced by Lactobacillus sake 1 and Lactobacillus curvatus 5 presented the highest thermal stability. The bacteriocin of Lactobacillus sake 1 was the most stable to pH variations. All LAB produced bacteriocin in the range of temperature from 4oC to 30oC and this property is of great interest for future applications in refrigerated meat products.