Anais do Congresso Paranaense de Microbiologia
IV Congress of Microbiology in Paraná

Salmonella is one of the main genera of microorganisms responsible for foodborne disease outbreaks, with Salmonella enterica subsp. enterica is one of the major causes of salmonellosis in humans. This disease can be caused by the consumption of animal origin foods contaminated by bacteria of the Salmonella genus, such as milk and dairy products. Kefir is a fermented milk produced from kefir grains which are composed of lactic acid bacteria, acetic acid bacteria, yeasts and their products. The beverage is homemade fermented, and the adequacy handling of the grains is an important step to avoid contamination of the beverage by spoilage and pathogenic microorganisms. The present study aimed to detect the presence of Salmonella sp. in 20 milk kefir samples handmade, donate by families in Londrina/PR, and to evaluate the presence of antimicrobial activity of lactic acid bacteria (LAB) isolated from these samples against the strain of Salmonella Enterica enterica ATCC 13076, followed the modified spot-on-the-lawn method. The analyses were performed at the Laboratório de Inspeção de Produtos de Origem Animal of Universidade Estadual de Londrina, in 2021. The positive samples in the biochemical tests followed molecular analysis by Polymerase Chain Reaction. The genera Salmonella was not detected in none of the samples. Two of the 20 samples showed positive results in selective differential plating and in biochemical tests, with absence confirmed by molecular analysis. A total of 575 colonies of lactic acid bacteria were isolated from the 20 kefir samples, with 98% (564) showing a translucent halo formation, indicating sensitivity of the Salmonella strain to substances produced and released by LABs. The antagonistic activity of LABs on Salmonella can be explained by several factors, including nutrient competition, enzymatic activity and the presence of metabolism products, which inhibit the growth of various bacteria. The isolation of LABs with the potential to inhibit the growth of undesirable, pathogenic and/or deteriorating microorganisms is a biocontrol strategy that can be used in food, improving the shelf life and microbiological quality of the product. Further studies are necessary to identify the LAB and their metabolites responsible for inhibiting the growth of Salmonella Enterica enterica ATCC 13076.