Indicator microorganisms, Salmonella, Listeria monocytogenes, Staphylococcal enterotoxin, and physicochemical parameters in requeson cheese

Abstract

Requeson cheese is an artisanal dairy product widely consumed in Latin America. However, no data is available on its microbiological and physicochemical quality. Eighty-four samples were collected. Identification and enumeration of indicator microorganisms and pathogens were done by conventional culture methods, meanwhile staphylococcal enterotoxin by immunoassay. Bromatological parameters were measure collection day. Indicator and pathogenic microorganisms per samples were aerobic mesophilic bacteria (n = 100), coliform bacteria (n = 100), molds-yeasts (n = 70), Staphylococcus aureus (n = 74), and Salmonella (n = 3). Neither Listeria monocytogenes nor Staphylococcal enterotoxin was detected. Temperature ranged from 3 to 19°C, pH from 5.1 to 6.9, acidity from 0.1 to 0.7%, and sodium from 290 to 3970 mg/100 g. Protein content ranged from 2.1 to 13% and lipids from 4.1 to 13%. Starch as adulterant was present in 56 samples.\tKey words: Indicator microorganism, Salmonella, Listeria monocytogenes, Staphylococcal enterotoxin, macronutrients, sodium.