The aim of this study was to evaluate the effect of gamma irradiation (1, 2 and 3 kGy) on the bacteriological quality and sensory perception of refrigerated raw whole milk. Moreover, physiochemical and bacteriological parameters were monitored during 60 days of storage at 4C. All of the irradiated samples, mainly 2 and 3 kGy, exhibited a lower (P < 0.05) bacterial load than the nonirradiated samples. During storage, the mesophilic count and titratable acidity did not increase in the irradiated samples. The consumers were able to differentiate all of the irradiated samples from the control group (P < 0.05); however, positive attributes were used to describe the irradiated samples. The present study indicates that the 2 kGy irradiation dose improved the bacteriological quality of raw whole milk and likely did not negatively affect sensory characteristics by maintaining a constant mesophilic count and titratable acidity over the 60 days of refrigerated storage. PRACTICAL APPLICATIONSThe prevalence of foodborne diseases and huge economic losses from food industries in developing countries has markedly increased. Taking into account the dairy products, raw milk represents the main source of foodborne infections. To investigate an alternative conservation method, three gamma irradiation doses (1, 2 and 3 kGy) were applied in refrigerated raw whole milk. After, bacteriological and sensory qualities of this milk were investigated. In addition, mesophilic count and titratable acidity were analyzed during 60 days of storage under refrigeration (4 ± 1C). On 0 day, all irradiation doses decreased (P < 0.05) the bacterial load of raw whole milk compared with nonirradiated samples. Moreover, both parameters evaluated during storage period (mesophilic bacterial count and titratable acidity) were stable in samples treated with 1, 2 and 3 kGy. However, rancid odors and flavors were perceived on the samples irradiated with 3 kGy. Therefore, in our study, the 2 kGy dose was recommended for raw whole milk because of the positive effects on bacterial quality and minimal sensory changes.

RESUMOTrês procedimentos foram adotados na elaboração de queijo de minas frescal: fabricação tradicional, com adição de ácido lático e com Lactobacillus acidophilus. As amostras dos queijos foram analisadas quanto à composição e, durante o período de estocagem de 30 dias, quanto à acidez -pH e acidez titulável -e contagem de L. acidophilus. A análise sensorial foi realizada por métodos sensoriais afetivos. A composição dos queijos nos diferentes procedimentos apresentou-se de acordo com os padrões esperados, com exceção do teor de gordura, que foi maior no queijo com adição de ácido lático. Durante a armazenagem, ocorreu aumento da acidez titulável em todos os procedimentos. A contagem de L. acidophilus foi acima de 10 8 UFC/g, caracterizando populações suficientes para classificar o queijo como alimento probiótico. Na análise sensorial, o de queijo de minas com a adição do probiótico foi o preferido pelos julgadores. O queijo de minas frescal foi apropriado para incorporação do probiótico, e o uso de L. acidophilus melhorou a qualidade sensorial e não alterou os parâmetros físico-químicos. Palavras-chave: queijo, probióticos, Lactobacillus acidophilus, ácido lático ABSTRACT Minas frescal cheese was produced in three different