Temporal and geographical comparison of bulk tank milk and water microbiota composition in Brazilian dairy farms.

This study investigated the relationship between the bacterial communities of bulk tank milk (BTM) and water used in Brazilian dairy farms. We also explored the association between BTM microbiota and its quality parameters (i.e., somatic cell count [SCC] and total bacteria count [TBC]). Water and BTM samples were collected twice for high throughput metataxonomic characterization. Milk samples were collected for SCCs, TBCs, and antimicrobial residue analysis. Water samples were submitted for physico-chemical and microbiological analyses. Overall, the BTM bacterial community was not influenced by the water microbiota. Furthermore, a higher number of Bacillus spp. and a tendency toward a higher number of Lactococcus spp. was associated with a higher TBC, and consequently could be used as an indicator of milk quality. A higher number of Streptococcus spp. and a tendency toward a higher number of Staphylococcus spp. were associated with a higher SCC. Apart from a variation on the content of the Bacillus taxa, no effect of sampling time on BTM bacterial community was observed. Finally, a negative correlation between the number of different species (richness) on BTM and SCC was found.

Milk Fermented by Lactobacillus paracasei NCC 2461 (ST11) Modulates the Immune Response and Microbiota to Exert its Protective Effects Against Salmonella typhimurium Infection in Mice.

Probiotics form a promising strategy to maintain intestinal health. Milks fermented with probiotic strains, such as the Lactobacillus paracasei ST11, are largely commercialized in Brazil and form a low-cost alternative to probiotic pharmaceutical formulations. In this study, we assessed the probiotic effects of milk fermented by L. paracasei ST11 (administered through fermented milk) in a Salmonella typhimurium infection model in BALB/c mice. We observed in this murine model that the applied probiotic conferred protective effects against S. typhimurium infection, since its administration reduced mortality, weight loss, translocation to target organs (liver and spleen) and ileum injury. Moreover, a reduction in the mRNA expression of pro-inflammatory cytokines such as IFN-γ, IL-6, TNF-α and IL-17 in animals that received the probiotic before challenge was observed. Additionally, the ileum microbiota was better preserved in these animals. The present study highlights a multifactorial protective aspect of this commercial probiotic strain against a common gastrointestinal pathogen.

Microbial shifts in Minas artisanal cheeses from the Serra do Salitre region of Minas Gerais, Brazil throughout ripening time.

The Minas artisanal cheese is a traditional product in its way of producing. Produced in the Minas Gerais state, Brazil, this cheese is made using raw cow's milk with the addition of an endogenous starter culture called "pingo", responsible for inoculating specific microorganisms that could enhance flavor and sensorial aspects. There are seven regions able to produce and commercialize this product - Araxá, Campo das Vertentes, Canastra Cerrado, Serra do Salitre, Serro and Triângulo Mineiro. This study aimed to assess the bacterial community of raw milk, endogenous starter culture and to uncover possible shifts in the bacterial community of the rind and core of cheeses at sixty days of ripening located in the Serra do Salitre region by Illumina MiSeq 16S rRNA gene amplicon sequencing. Raw milk and starter culture are responsible for inoculating specific bacteria into the cheese, with Planococcaceae and Streptococcaceae being prevalent throughout ripening time. The Planococcaceae family seems to develop strong interactions with the Leuconostocaceae family on the surface of these cheeses, and is associated with environmental aspects of the region, probably leading to a microbial signature of these products. Additionally, abiotic factors such as geographical location, moisture and acidity are major drivers in the microbial shift.

Detecção de genes toxigênicos, susceptibilidade antimicrobiana e antagonismo in vitro de Staphylococcus spp. isolados de queijos artesanais / Detection of toxigenic genes, susceptibility antimicrobial and in vitro antagonism of Staphylococcus spp. isolated from artisanal cheeses

Cepas de Staphylococcus spp. molecularmente identificadas foram submetidas à Reação em Cadeia da Polimerase (PCR), utilizando-se iniciadores específicos para a detecção de genes codificadores de enterotoxinas clássicas (SEA, SEB, SEC, SED, SEE) e da Toxina-1 da Síndrome do Choque Tóxico (TSST-1). Foi realizada PCR-Multiplex para detecção dos genes sea, sec, sed e see. Para seb e tst, foram realizadas PCR-Uniplex. Além disso, foi analisado o perfil de susceptibilidade das cepas a antimicrobianos de diferentes classes e foi verificado antagonismo in vitro entre Lactobacillus spp. e as cepas estudadas. Genes codificadores de enteroxinas clássicas, assim como de TSST-1, não foram encontrados. Em relação ao antibiograma, Sulfonamida, Penicilina, Ceftazidima e Oxacilina apresentaram os maiores percentuais de resistência (100, 80, 60 e 40%, respectivamente). Os demais antimicrobianos foram eficientes em percentuais acima de 70%. Lactobacillus spp. foram capazes de inibir o desenvolvimento in vitro de Staphylococcus spp. Conclui-se que as cepas estudadas não possuem genes codificadores da produção de enterotoxinas clássicas e TSST-1, são sensíveis à maioria dos antimicrobianos e são inibidos por bactérias do gênero Lactobacillus.