Correlating mesophilic counts to the pseudo-CMP content of raw milk / Correlação entre contagem de mesófilos e índice de Pseudo-CMP em leite cru

A presente comunicação objetivou avaliar a quantificação do caseínomacropeptídeo (CMP), bem como diferenciá-lo (devido à adulteração com soro) do pseudo-CMP (devido à proteólise bacteriana) em amostras de leite cru coletadas nos domicílios do sul do Brasil. Os resultados reforçam a necessidade de práticas higiênicas durante a ordenha e estocagem do leite. As amostras de leite estudadas não estavam adulteradas por adição de soro, mostrando que a análise por cromatografia de exclusão por tamanho deve ser complementada a fim de revelar a identidade do peptídeo (CMP ou pseudo-CMP). A contagem bacteriana total (TBC) também se mostrou útil como indicador da contaminação do leite por micro-organismos proteolíticos, uma vez que uma relação diretamente proporcional entre TBC e pseudo-CMP foi estabelecida.(AU)

Cleaning conveyor belts in the chicken-cutting area of a poultry processing plant with 45°c water.

Conveyor belts are widely used in food handling areas, especially in poultry processing plants. Because they are in direct contact with food and it is a requirement of the Brazilian health authority, conveyor belts are required to be continuously cleaned with hot water under pressure. The use of water in this procedure has been questioned based on the hypothesis that water may further disseminate microorganisms but not effectively reduce the organic material on the surface. Moreover, reducing the use of water in processing may contribute to a reduction in costs and emission of effluents. However, no consistent evidence in support of removing water during conveyor belt cleaning has been reported. Therefore, the objective of the present study was to compare the bacterial counts on conveyor belts that were or were not continuously cleaned with hot water under pressure. Superficial samples from conveyor belts (cleaned or not cleaned) were collected at three different times during operation (T1, after the preoperational cleaning [5 a.m.]; T2, after the first work shift [4 p.m.]; and T3, after the second work shift [1:30 a.m.]) in a poultry meat processing facility, and the samples were subjected to mesophilic and enterobacterial counts. For Enterobacteriaceae, no significant differences were observed between the conveyor belts, independent of the time of sampling or the cleaning process. No significant differences were observed between the counts of mesophilic bacteria at the distinct times of sampling on the conveyor belt that had not been subjected to continuous cleaning with water at 45°C. When comparing similar periods of sampling, no significant differences were observed between the mesophilic counts obtained from the conveyor belts that were or were not subjected to continuous cleaning with water at 45°C. Continuous cleaning with water did not significantly reduce microorganism counts, suggesting the possibility of discarding this procedure in chicken processing.

Short communication: Presence of neutral metallopeptidase (npr) gene and proteolytic activity of Bacillus cereus isolated from dairy products.

The control of proteolytic microorganisms is one of the main challenges of the dairy industry, due to their spoilage activity that jeopardizes the quality of their products. Seventy-four Bacillus cereus strains isolated from powdered, UHT, and pasteurized milks were tested for the presence of the neutral metallopeptidase (npr) gene and proteolytic activity at 7, 10, 25, 30, and 37°C. All strains had the npr gene, and proteolytic activity increased with the incubation temperature. The obtained results highlight the relevance of B. cereus as a spoiling agent in the dairy industry in terms of its genetic predisposition for proteolytic capacity, especially at room temperature.

Production of mortadella: behavior of Listeria monocytogenes during processing and storage conditions.

The presence of Listeria monocytogenes in ready-to-eat meat products is cause of concern to the food industry as well as to health authorities. Studies were conducted to evaluate the presence of L. monocytogenes in mortadellas acquired at retail stores and to evaluate the fate of two levels of a L. monocytogenes pool spiked in two different formulations of the product, cooked under commercial conditions and stored at refrigeration (7°C) and room temperature (25°C). Among the samples collected at different retail stores, 26.7% harboured L. monocytogenes. Regarding to the fate of L. monocytogenes in mortadella, periodically, samples were taken and the surviving L. monocytogenes cells in the spiked products were counted by the MPN procedure. Populations of <0.35 MPN/g of L. monocytogenes were found in these samples. It could be concluded that the heat treatment was effective to reduce 3-log of L. monocytogenes independent of formulation or storage conditions.