RESUMO
O leite integral e a bebida láctea UAT são submetidos ao mesmo tratamento térmico, mas são produtos diferentes, já que na bebida láctea é permitida a adição de até 50% de soro lácteo. Neste estudo, objetivou-se avaliar as características microbiológicas destes produtos com relação à legislação vigente do Ministério da Agricultura, Pecuária e Abastecimento (MAPA) e, ainda, da população psicrotrófica, ao longo do período de validade. Foram analisadas 150 amostras, 75 de cada produto, a partir de cinco diferentes marcas comerciais nacionais. As 15 amostras de cada marca foram subdivididas em três lotes: início, meio e final do período de validade, cada qual com cinco amostras do mesmo lote. Verificou-se para o leite que todas as amostras de leite UAT estavam de acordo com a legislação vigente. A população de psicrotróficos aumentou em 26,6% das amostras depois que foram abertas e mantidas sob refrigeração por 48 horas. Os resultados para a bebida láctea evidenciaram que 12% das amostras estavam em desacordo com o estabelecido pela legislação vigente. A população de psicrotróficos aumentou em 36% das amostras depois que foram abertas e mantidas sob refrigeração por 48 horas. Tais resultados devem servir de alerta para a necessidade de fiscalização mais rigorosa da bebida láctea UAT, pois parte das amostras não atenderam aos padrões microbiológicos estabelecidos pela legislação.
UHT milk and dairy drinks are submitted to the same heat treatment, but they are different products, since the addition of up to 50% of whey is allowed in dairy drinks. The aim of this study was to evaluate the microbiological characteristics of these products in relation to current legislation, during the course of their shelf life. In the present study, 150 samples, 75 of each type of product, from 5 different national brands were analyzed. The 15 samples of each brand were separated into 3 lots containing 5 samples each, analyzed at the beginning, middle and end of the validity period. Upon microbiological analysis all UHT milk samples were in conformance with current legislation. After the samples were opened and chilled for 48 hours, 26.6% of them presented an increased psychrotrophic population. The dairy drink results showed that 12% of the samples were out of conformance with the current legislation. After the samples were opened and chilled for 48 hours, 36% of them presented an increased psychrotrophic population. These results should be considered as an alert in regard to the need for rigorous inspection of UHT milk and dairy drink products.
Assuntos
Alimentos Integrais , Leite/microbiologia , Tecnologia de Alimentos/métodos , Técnicas Bacteriológicas/métodosRESUMO
Nitric oxide (NO) plays a key role in body temperature (Tb) regulation of mammals, acting on the brain to stimulate heat loss. Regarding birds, the putative participation of NO in the maintenance of Tb in thermoneutrality or during heat stress and the site of its action (periphery or brain) is unknown. Thus, we tested if NO participates in the maintenance of chicks' Tb in those conditions. We investigated the effect of intramuscular (im; 25, 50, 100mg/kg) or intracerebroventricular (icv; 22.5, 45, 90, 180 microg/animal) injections of the non selective NO synthase inhibitor L-NAME on Tb of 5-day-old chicks at thermoneutral zone (TNZ; 31-32 degrees C) and under heat stress (37 degrees C for 5-6h). We also verified plasma and diencephalic nitrite/nitrate levels in non-injected chicks under both conditions. At TNZ, 100mg/kg (im) or 45, 90, 180 microg (icv) of L-NAME decreased Tb. A significant correlation between Tb and diencephalic, but not plasma, nitrite/nitrate levels was observed. Heat stress-induced hyperthermia was inhibited by all tested doses of L-NAME (im and icv). Tb was correlated neither with plasma nor with diencephalic nitrite/nitrate levels during heat stress. These results indicate the involvement of brain NO in the maintenance of Tb of chicks, an opposite action of that observed in mammals, and may modulate hyperthermia.
