O objetivo deste trabalho foi isolar e caracterizar cepas de Lactobacillus e Bifidobactérias
a partir de leites fermentados comerciais e analisar sua resistência ao pH ácido e sais biliares.
Os microrganismos foram isolados de leites fermentados comerciais através da técnica ‘spreadplate’
em meio seletivo MRS suplementado com neomicina, paromomicina, ácido nalidÃxico
e cloreto de lÃtio. Posteriormente, as cepas foram caracterizadas conforme a coloração de
Gram e a prova da catalase. Foi possÃvel identificar através do kit comercial Api 20A os
microrganismos Actinomyces israelli, Actinomyces haeslundii, Lactobacillus acidophilus/
jensenii e Bifidobacterium spp 2 e através do kit comercial Api 50CHL Medium foi possÃvel
identificar os microrganismos Lactococcus lactis ssp lactis 2 e Lactobacillus paracasei ssp
paracasei 1. Foram realizados testes de resistência em pH de 3,0; 2,5 e 2,0 durante 3 e 6 horas
e resistência aos sais biliares na concentração de 0,3%. Ambas as cepas foram resistentes ao
pH de 3,0 durante 3 horas e 6 horas e aos sais biliares.
The aim of this study was to isolate and to
characterize Lactobacillus and Bifidobacterias strains
from fermented commercial milks and to analyze
its resistance to acid pH and bile salts. The
microorganisms were isolated from fermented
commercial milks from ‘spread-plate’ technique in
MRS selective medium supplemented with
neomycin, paromomicin, nalidixic acid and lithium
chloride. After, the strains were characterized as
coloration de Gram and catalase test. Were possible
to identify through the commercial kit Api 20A
microorganisms like Actinomyces israelli,
Actinomyces haeslundii, Lactobacillus acidophilus/
jensenii and Bifidobacterium spp 2 and through the
commercial kit Api 50CHL Medium were possible
to identify the microorganisms Lactococcus lactis
ssp lactis 2 and Lactobacillus paracasei ssp
paracasei 1. Were realized resistance tests in 3,0;
2,5 and 2,0 pH during 3 and 6 hours and resistance
to bile salts in the concentra tion of 0,3%. Both the
strains were resistant to 3,0 pH during 3 and 6 hours
and to presence of bile salts.
Index terms: Bifidobacterias, Lactobacillus,
probiotic, fermented milks, isolation.
