A total of 480 milk samples were analyzed in four repetitions with four preservative treatments (no preservative, Bronopol, Bronolat and Brononata), three storage times at temperatures up to 4 °C (24, 48 and 72hours after reception), five different water additions (0.0, 2.5, 5.0, 7.5 and 10.0%) and two analytical instruments (electronic cryoscope and FTIR). The objective of this study was to evaluate the effect of these parameters in the determination of the freezing point by the reference method and by Fourier transform infrared spectroscopy, thus determining the best analytical conditions and establishing a mathematical equation for electronic determination by FTIR spectroscopy. Bronolat was the best preservative and Brononata was the worst and is not recommended to analyze freezing point by FTIR. The storage time of the samples did not interfere in the analytical determinations by the precision method and by FTIR.

Some Lactobacillus strains may contribute to the health of the host when administered in adequate concentrations, demonstrating their probiotic potential. In contrast, Listeria monocytogenes is a foodborne pathogen that can cause enteropathy, meningoencephalitis, abortion, and septicemia. The aim of this survey was to evaluate the in vitro and in vivo probiotic potential of Lactobacillus plantarum B7 and Lactobacillus rhamnosus D1, isolated from Minas artisanal cheese of the Serra da Canastra (Minas Gerais, Brazil), against Lis. monocytogenes. We submitted B7 and D1 to in vitro testing (antibiogram, tolerance to bile salts and artificial gastric fluid, and spot-on-lawn) and in vivo testing (relative weight gain in mice). Both Lactobacillus strains demonstrated in vitro inhibitory activity against Lis. monocytogenes, as well as sensitivity to antimicrobials and resistance to gastric acids and bile salts. In the in vivo assays, mice treated with D1 gained more weight than mice in the other groups. These results indicate that D1 could have higher probiotic potential than B7 because improvements in feed conversion may help animals fight infection.

Lactobacillus spp. are lactic acid bacteria which have important implications for the food industry due to their fermentation capacities. The aims of this research were to produce fermented goat milks with Lactobacillus plantarum B7 and Lactobacillus rhamnosus D1, isolated from Brazilian artisanal cheeses, and to evaluate their physico-chemical, microbiological and sensorial qualities during 30 days of storage at 7°C. The goat milks, fermented by B7, D1, co-culture and a Lactobacillus casei Shirota control, possessed acceptable physico-chemical characteristics to meet fermented milk standards established by Brazilian legislation and maintain the viability of Lactobacillus spp. throughout the shelf life of the products. The products were microbiologically safe. D1 fermented goat milk gave higher consumer sensory quality acceptance and purchase intention (p<0.05) than other treatments, thus Lactobacillus rhamnosus D1 is recommended for fermented goat milk production.

Leite e seus derivados são alimentos que se destacam pelo elevado teor nutritivo. Essa característica permite que seja encontrada uma grande diversidade de micro-organismos nesses produtos, incluindo aqueles considerados desejáveis e indesejáveis. Associado a isso, um elevado volume de leite tem sido produzido mundialmente, demandando que métodos mais práticos e acurados, como a espectrometria de massa MALDI-TOF, sejam aplicados para avaliação microbiológica de produtos lácteos. Essa metodologia se baseia na ionização e dessorção de proteínas microbianas, que em seguida são aceleradas em um tubo a vácuo. De acordo com o tempo de voo ao longo do tubo das diferentes partículas ionizadas que compunham a amostra, são formados espectros característicos que podem ser comparados aos espectros presentes no banco de dados do aparelho, permitindo uma identificação do micro-organismo. Muitos estudos científicos têm demonstrado que a identificação por MALDI-TOF de distintos micro-organismos isolados de produtos lácteos (leite fluido, queijos e leites fermentados) foi compatível com o resultado obtido por métodos de sequenciamento genético (gene rRNA 16S), que é considerado o padrão-ouro para identificação microbiana. Apesar de ser um método novo e que demanda um considerável investimento para aquisição do aparelho, seu desempenho tem sido satisfatório e promissor. Portanto, há uma grande perspectiva futura para sua utilização de forma mais efetiva na identificação de micro-organismos provenientes de produtos lácteos.