Evaluation of phenotypical safety aspects of lactic acid bacteria isolated from artisanal Colonial-type cheese from the south of Brazil

Abstract

This study aimed to isolate and evaluate lactic acid bacteria (LAB) from artisanal Colonial-type cheeses commercialized in open markets in Pelotas, RS, in terms of phenotypic safety aspects. Around 105 strains were isolated, 73 were characterized as Gram-positive and catalase-negative, and evaluated for phenotypic aspects of virulence. All strains were gelatinase and DNase negative. Regarding hemolytic activity, there was the detection of seven strains as α and two as β-hemolytic, resulting in 64 strains of LAB for antimicrobial susceptibility assessment. These isolates were sensitive to chloramphenicol and tetracycline antibiotics. For the other antimicrobials, they showed resistance to ciprofloxacin (93.5%, 58/64), oxacillin 98.4% (63/64), penicillin G 51.6% (41/64), and vancomycin (85.9%, 54/64). Based on these results, the isolates were potentially safe, a conclusion that contributes to the search for new beneficial strains for the dairy industry.