Minas artisanal cheese, produced in the Campo das Vertentes region of Brazil, is made from raw milk and endogenous starter cultures. Although this cheese is of great historical and socioeconomic importance, little information is available about its microbiological and physical-chemical qualities, or about its beneficial microbiota. This work was aimed at evaluating the qualities of the cheese and the components used for its production, comparing samples collected during the dry and rainy seasons. We also conducted molecular identification and isolated 50 samples of lactic acid bacteria from cheese (n=21), water (n=3), raw milk (n=9), and endogenous starter culture (n=17). The microbiological quality of the cheese, water, raw milk, and endogenous starter culture was lower during the rainy period, given the higher counts of coagulase-positive Staphylococcus and total and thermotolerant coliforms. Enterococcus faecalis was the lactic acid bacteria isolated most frequently (42.86%) in cheese samples, followed by Lactococcus lactis (28.57%) and Lactobacillus plantarum (14.29%). Lactobacillus brevis (5.88%), Enterococcus pseudoavium (5.88%), Enterococcus durans (5.88%), and Aerococcus viridans (5.88%) were isolated from endogenous starter cultures and are described for the first time in the literature. The lactic acid bacteria identified in the analyzed cheeses may inhibit undesirable microbiota and contribute to the safety and flavor of the cheese, but this needs to be evaluated in future research.

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The microbiota of lactic acid bacteria (LAB) from Minas artisanal cheese was evaluated. Samples of Minas artisanal cheese were collected at the farms in the region of Araxá, Brazil, over two seasons. Molecular approaches were used to assess the biodiversity of the isolates. The median value of the counts of LAB ranged from 6.4 to 9.5 log units in cheeses throughout the ripening period, in both seasons. The genera of Lactobacillus, Enterococcus, Pediococcus, and Lactococcus were found. L. plantarum and L. rhamnosus were the prevailing species during both seasons, suggesting they may play a role in the development of the cheese attributes. Enterococcus rivorum was identified in one sample and it was probably the first description in cheeses. This is an important report describing the varieties of LAB in this cheese and the identification of its lactic communities could be a source of strains with specific properties.Aislamiento e identificación de las baterias ácido-lácticas del queso brasileño Minas artesanal RESUMEN Se evaluó la microbiota de la bacteria ácido-láctica (BAL) del queso Minas artesanal. Se recogieron muestras del queso Minas artesanal en granjas de la región de Araxá, Brasil, durante dos estaciones. Se utilizaron enfoques moleculares para examinar la biodiversidad de los aislados. El valor medio de los recuentos de BAL fue de entre 6,4 y 9,5 unidades log en los quesos durante el periodo de maduración, en las dos estaciones. Se encontraron los géneros Lactobacillus, Enterococcus, Pediococcus, y Lactococcus. L. plantarum y L. rhamnosus fueron las especies predominantes durante las dos estaciones, sugiriendo que podrían jugar un papel importante en el desarrollo de los atributos del queso. Se identificó Enterococcus rivorum en una muestra y probablemente fue la primera descripción en los quesos. Este es un importante estudio que describe las variedades de BAL en este tipo de queso y la identificación de sus comunidades lácticas podría ser una fuente de cepas con propiedades específicas. ARTICLE HISTORY

The interaction between the surface of stainless steel and Bacillus cereus was studied in terms of the characteristics of interfacial interaction determined from the measurement of the contact angle of the surface of B. cereus and stainless steel in the presence or absence of B. cereus adherence. The microtopographies and the roughness of the surface of stainless steel and stainless steel adhered by B.cereus were evaluated with the help of atomic force microscopy and perfilometry. The strain of B. cereus studied was considered hydrophilic, whereas the stainless steel was considered hydrophobic. The adhesion was not thermodynamically favorable ( G adhesion > 0) between the stainless steel and the strain of B. cereus studied. Thus, the interaction between them was not favored by the thermodynamic aspect of adhesion.There was no difference (p > 0.05) in the roughness of the surfaces of stainless steel adhered by B. cereus when analyzed by atomic force microscope and perfilometry.

Minas artisanal cheese is made from endogenous starter cultures, including lactic acid bacteria (LAB). Some LAB may possess probiotic potential. Thus, this study aimed to evaluate the in vitro probiotic properties of lactobacilli isolated from Minas artisanal cheeses produced in Minas Gerais. Ten samples of lactobacilli, formerly isolated from those cheeses, were submitted to the following assays: antimicrobial susceptibility, tolerance to artificial gastric juice and biliary salts, production of hydrogen peroxide and antagonism against pathogenic and non-pathogenic micro-organisms. Only L. plantarum (C0) was sensitive to all tested antimicrobials, while the other LAB samples were resistant to at least one drug. Six samples were tolerant to artificial gastric juice, and L. brevis (A6) even grew in that medium. Three samples were tolerant to biliary salts. Only L. brevis (E35) produced hydrogen peroxide. Difference (P< 0.05) was observed among the means of inhibition haloes of lactobacilli against Enterococcus faecalis ATCC 19433 and Lactobacillus plantarum C24 in spot-on-the-lawn assay. All samples of lactobacilli inhibited Escherichia coli ATCC 25922, Salmonella enterica var. Typhimurium ATCC 14028 in co-culture antagonism test (P< 0.0001). Most lactobacilli samples showed in vitro probiotic potential. From the tested samples, L. brevis (A6) presented the best results considering all in vitro probiotic tests.