Lactobacillus acidophilus antagonistic action against pathogenic strains inoculated in the fermented milk / Ação antagonista de Lactobacillus acidophilus frente a estirpes patogênicas inoculadas em leite fermentado

Abstract

With the present study aimed to evaluate the antagonistic action of Lactobacillus acidophilus front of Escherichia coli , Staphylococcus aureus and Listeria monocytogenes . In vitro tests were performed using Petri dishes with MRS agar and the milk fermented with Lactobacillus acidophilus also analyzed the chemistry and physical characteristics of the product during 35 days of storage under refrigeration. It has been observed in vitro formation of inhibition zones, ranging from 6 to 18 mm diameter, compared to the tested pathogens by lactic culture raises, indicating the possibility of producing organic acids, bacteriocins or other growth-inhibiting substances. In the fermented milk prepared, during storage, the probiotic micro-organism tested was able to inhibit the growth of E. coli O157: H7 and L. monocytogenes ; and the log cycle reduction of S. aureus .