Efeitos do período de maturação de queijos sobre a microbiota deteriorante e listeria monocytogenes

Abstract

In order to verify the effect of the maturation period on the development of micro-organisms two studies were conducted, in which the first one was developed with cheeses produced with raw milk (n = 7) for evaluation of aerobic microorganisms mesophilic counts, total coliforms and Escherichia coli, and the second one with cheeses produced with laboratorial sterilized milk (n = 7) for the assessment of the counts of Listeria monocytogenes inoculated. In both studies, the cheeses were matured under controlled conditions of temperature (7.5 ± 1.5 ° C) and humidity (45 ± 5%), for 60 days. Analysis of the prime materials (raw milk and sterilized milk), the curd immediately after production, the cheeses on the first day (Day 01) and every ten days (days 10, 20, 30, 40, 50 and 60) were carried out; Also, the cheeses' moisture were estimated. Mesophilic aerobic counts were 5.77 CFU/mL log in milk sample, 6.67 log CFU/g in curd sample, 8.92 log CFU/g in cheese sample within twenty days of ripening, when it reached its maximum count and 7.24 log CFU/g at the sixtieth day of ripening. Total coliform counts were: 5.47 log CFU/mL in milk sample, 6.33 log CFU/g in curd sample, 7.73 log CFU/g on the tenth day of ripening, when it reached its maximum count and 5.18 log CFU/g at the sixtieth day. E. coli showed counts of 2.52 log CFU/mL in milk sample, 3.48 log CFU/g in curd sample, 5.19 log CFU/g with twenty days of ripening when reached its maximum count and 2.30 log CFU/g at the sixtieth day of ripening. L. monocytogenes counts were 6.50 log CFU/g in curd sample, 8.09 log CFU/g on the thirtieth day, when it reached its maximum count and 7.66 log CFU/g within sixty days of ripening. With the results it was concluded that the 60-day maturation period was not enough to ensure the hygiene and safety of cheeses considering the behavior of microorganisms studied under the circumstances analyzed.

Processos Da Maturação Em Queijos

“…A proteólise em queijo azul se inicia com 5 dias e se torna acelerado devido a presença de enzimas ativas, os teores de tirosina e triptofano se tornam bons indicadores da maturação, nesse caso o teor de tirosina está mais elevado do que o de triptofano (PACIULLI, 1996). Em queijo feito à base de leite de cabra ocorre uma maior hidrólise de caseína em até 10 dias de maturado, mas durante os 30 dias o processo se torna lento.…”