ABSTRACT
Sheep milk is the third most consumed milk in Brazil. It is much appreciated for its nutritional status and is important for children that have problems with cow milk. Little information is known about the chemical, physical and microbiological composition of sheep milk from South Brazil. Thus, the aim of this study was to describe chemical and microbiological characteristics of sheep milk produced on two rural properties located in southern Brazil (Paraná and Rio Grande do Sul). The chemical composition of sheep milk was 17.32 g/100 g total solids, 5.86 g/100 g total protein, 4.46 g/100 g casein, 1.08 g/100 g whey protein, 7.28 g/100 g fat, 0.93 g/100 g ash, and 3.41 g/100 g lactose. High somatic cell count (1.7x106 cells/mL), total mesophilic bacterias (16.0x106 CFU/mL) and psychrotrophics (5.8x106 CFU/mL) were observed. Growth of Staphylococcus aureus, enterobacteria and coliforms occurred in 100% of the samples, and 45% of the samples showed growth of Escherichia coli. The sheep milk physical-chemical and microbiology parameters are similar to those presented in the literature for other countries but somatic cell count presented high levels.
O leite de ovelha é o terceiro mais consumido no Brasil, e é muito apreciado devido ao seu aspecto nutricional. Pouca informação a respeito da composição química e microbiológica do leite de ovelha no Brasil é conhecida. O objetivo deste trabalho foi caracterizar o leite ovino produzido em duas propriedades rurais localizadas no Sul do Brasil (Paraná e Rio Grande do Sul). A composição química do leite de ovelha foi 17,32 g/100 g de sólidos totais; 5,86 g/100 g de proteína total; 4,46 g/100 g de caseína; 1,08 g/100 g de soro proteico; 7,28 g/100 g de gordura; 0,93 g/100 g de cinzas e 3.41 g/100 g de lactose. Altas contagens de células somáticas (1,7x106 células/mL), bactérias mesófilas (16,0 x106 UFC/mL) e psicrotróficos (5,8x106 UFC/mL) foram observadas. Multiplicação de Staphylococcus aureus, enterobactérias e coliformes ocorreu em 100% das amostras, 45% de amostras apresentou multiplicação de Escherichia coli. Os parâmetros físico-químicos e microbiológicos do leite ovino deste estudo são semelhantes a literatura para outros países, porém, a contagem de células somáticas foi elevada.
Subject(s)
Animals , Cattle , Female , Bacteria/isolation & purification , Milk/chemistry , Milk/microbiology , Brazil , Bacteria/classification , Colony Count, Microbial , Cheese/analysis , Cheese/microbiology , Mastitis , SheepABSTRACT
Los enterococos son constituyentes de la microflora de quesos artesanales y contribuyen a sus características organolépticas. También producen enterocinas que pueden prevenir el crecimiento de patógenos alimentarios. En este estudio se aislaron 27 cepas de enterococos a partir de leche y queso ovinos provenientes de la Patagonia (Argentina) y se investigó la producción de bacteriocinas. De las 27 cepas aisladas, 22 cepas de Enterococcus faecium y 1 cepa de E. faecalis inhibieron el crecimiento de Listeria innocua ATCC 33090. E. faecium Tw6 mostró la mayor actividad antimicrobiana entre las cepas estudiadas y se seleccionó con el propósito de caracterizar el principio activo y su espectro de inhibición. La tripsina abolió la actividad antilisteria, lo que sugiere que el compuesto activo es de naturaleza proteica; resultó ser estable al calor, resistente al pH y permaneció estable durante más de 12 meses. La masa molecular determinada mediante electroforesis fue aproximadamente de 5,6 KDa. La reacción en cadena de la polimerasa (PCR) mostró la presencia de múltiples secuencias de enterocinas (entA, entB, entP y entL50A/B). Las características físico-químicas y bioquímicas de las enterocinas producidas por E. faecium Tw6 las convierten en potenciales candidatas para ser utilizadas en la conservación de alimentos.
Enterococci are part of the microflora of artisan type cheese and contribute to their organoleptic characteristics. They also produce enterocins which can prevent the growth of food pathogens. In this study 27 enterococci strains were isolated from ovine milk and cheese produced at the Argentine Patagonia and they were investigated regarding their bacteriocin production. Of the 27 strains isolated. 22 Enterococcus faecium and one E. faecalis inhibited the growth of Listeria innocua ATCC 33090; E. faecium Tw6 showed the highest antimicrobial activity among the strains studied and it was selected with the purpose of characterizing the active principle and its inhibition spectrum. Trypsin abolished antilisteria activity, which suggests that the active component has a protein nature; it was heat stable, pH resistant, and it remained stable during more than 12 months. The molecular mass determined by electrophoresis was approximately 5.6 KDa. The polymerase chain reaction (PCR) showed the presence of multiple enterocin sequences (entA, entP, and ent50A/B). The physicochemical and biochemical characteristics of the enterocins produced by E. faecium Tw6 identify them as a potential candidates for use in food preservation.