Efeito protetor de Lactobacillus plantarum (B7) e L. rhamnosus (D1) de queijo Minas artesanal na infecção experimental por Escherichia coli EHEC e EIEC e o desenvolvimento de leite de búfala fermentado

Abstract

Lactic acid bacteria when ingested in adequate amounts confer benefits to consumer health. There are numerous studies on the activities performed by these probiotic micro-organisms in the gut and also in other parts of the body, such as the inhibition of various pathogenic bacteria; immune system modulation; aid in constipation; blood cholesterol reduction; anticarcinogenic activities, among others. The aim of this study was to evaluate the probiotic potential in vitro and in vivo of Lactobacillus plantarum B7 e Lactobacillus rhamnosus D1 isolated from Minas artisanal cheese Serra of the Canastra against enterohemorragic Escherichia coli (EHEC) O157:H7 and enteroinvasive Escherichia coli (EIEC), in order to develop a functional fermented milk inhibition using buffalo milk. In in vitro tests all tested lactic acid bacteria were able to produce inhibition zone against the pathogenic micro-organisms. No significant difference was observed (p> 0.05) in the inhibition ability by the samples of Lactobacillus, only in the susceptibility of each indicator. In in vivo tests, animals treated with Lactobacillus rhamnosus D1, which were challenged with EIEC were those with the best result of protection, with the ileum preserved in most animals. The milk fermented by L. plantarum B7 and L. rhamnosus D1 showed acidification ability statistically equal, and maintenance of appropriate lactobacilli counts (above 107 CFU/mL) during 28 days of storage under refrigeration (4-7oC). The results of the sensory analysis of the fermented milks stored for 14 and 28 days under refrigeration at 4-7ºC indicated similar preference for both milk fermented, with a median (4) corresponding to the degree of acceptance "liked ". In analysis by purchase intent, the fermented milk L. rhamnosus D1 had 63.28% and L. plantarum B7 had 61.31% in the two days of storage. Concluding, buffalo milk fermented with L. plantarum B7 and L. rhamnosus D1 have good acceptance, besides they have adequate probiotic potential, highlighting mainly L. rhamnosus D1.