Evaluation of the safety and quality of microbiological handmade cheese Serrano and its relation to physical and chemical variables the period of maturity.

Background: The handmade cheese serrano is a typical product created on small farms in the states of Santa Catarina and Rio Grande do Sul. Its main feature is to be manufactured from raw. Due to the physico-chemical phenomena that occur during maturation, this process is the only way to eliminate the pathogenic microorganisms that may be present contaminating the cheese. The present study aimed to evaluate the safety of handmade cheeses by isolation and identifi ca- tion of Listeria monocytogenes and Salmonella spp. and evaluate the microbiological quality through the isolation and quantifi cation of Staphylococcus aureus, Escherichia coli and total coliforms and relate the maturation time and variations physico-chemical with the contamination of handmade cheeses. Materials, Methods & Results: The experiment was conducted using 108 samples of handmade cheese Serrano from the towns that make up the mountainous region of SC, with maturation periods of 15, 30, 45 and 60 days. In each of the stages of maturation were analyzed twenty seven samples of cheeses, for the presence of Listeria monocytogenes by the method USDA/2009 and Salmonella spp. methodology according to ISO 6579/2007. The identifi cation and enumeration of Staphylococcus aureus, Escherichia coli and total coliform was performed in plates petrifi lmTM. Physicochemical analyzes consisted of determining moisture, acidity, fat and protein. In this study was evaluated a total of 108 samples, of these 63 (58.33%) were positive for total coliforms, 64 (59.26%) were positive for Escherichia coli and 36 (33.33%) showed counts of Staphylococcus aureus over 10 CFU / g. There was a decrease in the population of coliforms and Escherichia coli after 30 and 45 days of maturation, respectively. The enumeration of Staphylococcus aureus was not infl uenced by maturity period, however, there was a reduction in the count of this micro-organism from 15 to 45 days and after this period there was an increase in the population of the same. Salmonella spp. were not detected in any analyzed maturation periods. Lis- teria spp. were isolated in 21/108 (19.44%) of the samples analyzed, 18 (16.66%) were identifi ed as Listeria innocua and three (2.77%) as Listeria monocytogenes. The isolation of Listeria spp. decreased from 30 days of ripening and Listeria monocytogenes isolated at 30 and 45 days of ripening. The physicochemical results found in this study are presented in a range of normal variation, the maturation period only infl uenced the fat content, where a signifi cant decrease was observed from 15 to 30 days, and protein content which higher performed at the end of the period. Discussion: The presence of total coliforms, Escherichia coli and Staphylococcus aureus showed defi ciency in hygiene procedures during manufacturing or storage of the cheeses and the presence of Escherichia coli indicates fecal contamina- tion of food, suggesting that other enteropathogens may be present. The presence of Listeria innocua suggests that Listeria monocytogenes may be present contaminating the product. Listeria monocytogenes makes handmade cheese unfi t for hu- man consumption. Thus, it was not possible to check a minimum maturation period of handmade cheese with no or low count of micro-organisms evaluated. The great variation in the composition of the cheeses analyzed demonstrates the lack of standardization in the production of handmade cheese.