In vitro probiotic potential of Lactobacillus spp. isolated from fermented milks [Potencial probiótico in vitro de Lactobacillus spp. isolados de leites fermentados]

The potential of in vitro probiotic Lactobacillus spp. was evaluated in fermented milks marketed in Belo Horizonte, MG, Brazil. Of the samples analyzed, 86.7% had at least 10 6 CFU/mL of Lactobacillus spp., complying with the Brazilian quality standards for fermented milks. Furthermore, 56.7% had minimum count ranging from 10 8 to 10 9 CFU/mL, which is in accordance with legal parameters. The remaining 43.3% would not be able to satisfactorily guarantee benefits to consumers. The amount of Lactobacillus spp. varied between batches of products, which may indicate failures in monitoring during manufacture, transport or storage. All strains of Lactobacillus spp. showed some inhibitory activity against the indicator microorganisms, being more pronounced against pathogenic microorganisms than against non-pathogenic (P<0.05). Samples of Lactobacillus spp. showed different profiles of antimicrobial susceptibility, with an occurrence of cases of multidrug resistance. All strains tested showed sensitivity to bile salts (0.3%) and resistance to gastric pH (2.0). Lactobacillus spp. of commercial fermented milks should be present in higher amounts in some brands, be resistant to bile salts and have no multiple resistance to antimicrobials.