Dados do Trabalho

Título

ISOLATION OF AUTOCHTONOUS LACTIC ACID BACTERIA FROM MINAS ARTISANAL CHEESE PRODUCED WITH MILK FROM COWS WITH A2 ALLELE FOR β -CASEIN

Introdução

Lactic acid bacteria (LAB) are currently the subject of extensive research aimed at uncovering novel microorganisms that are both recognized as safe and with probiotic properties. Identifying new LAB would provide to the national market the opportunity for research and characterization of technologically viable and beneficial bacteria. Studies have isolated and identified LAB present in Minas artisanal cheese (QMA) from various producing regions, as well as characterizing some species as probiotic. The aim was to enumerate and characterize LAB from whey, milk, and QMA produced with milk from cows with the A2 allele for β-casein.

Material e Métodos

Six samples of whey-ferment used for QMA production, six samples of raw milk from cows with the A2 allele for β-casein, and six samples of QMA at different maturation periods (1, 7, 14, 21, 45, and 60 days) were collected. The collections were carried out during the rainy season. Two culture media, MRS and M17, were used to LAB research.

Resultados e Discussão

In whey and milk, the highest concentrations of LAB occurred on M17 agar, 8.48 and 5.89 log CFU/mL, respectively. In QMA, the LAB count was approximately 1.00 log CFU/mL higher when compared to MRS agar. There was no significant difference (p<0.05) over the maturation period for M17 agar. For MRS agar, the highest results were obtained at 14 and 21 days, 8.46 and 8.21 log CFU/mL, respectively. 86 distinct colonies were isolated with growth characteristics suggestive of LAB, such as relatively small colonies, round shape, white color, and delimited edges. 88.37% were Gram-positive bacteria. Regarding catalase test, 66.67% were catalase negative. Concerning morphology, 66.67% of the strains showed characteristics of cocci, and 33.33% were bacilli. 31 strains have been identified by MALDI-TOF spectrometry, of which 18 are LAB: eight Lactiplantibacillus plantarum, eight Levilactobacillus brevis, one Pediococcus pentosaceus, and one Lacticaseibacillus paracasei.

Conclusão

Milk and its derivatives remain as a good food matrix for the multiplication of autochthonous LAB, and new isolated strains are subject to in vitro and in vivo tests to assess their probiotic potential and subsequent application in functional foods.