Evaluation des caractères physico-chimiques et microbiologiques du lait pasteurisé partiellement écrémé produit par les laiteries de la wilaya de Mostaganem

Abstract

Milk, a complete food, constitutes an ideal environment for the growth of microbial alteration and/or pathogenic flora, treated by pasteurization, sufficient heat treatment for elimination of microorganisms, having double objective: allows the obtention of healthy milk and extend its shelf life. The objective of this study was the evaluation of the physicochemical and microbiological quality of partially skimmed pasteurized milk made within two dairies of Mostaganem province. A series of physicochemical (density, acidity, pH and total dry extract) and microbiological (search for total mesophilic aerobic germs at 30°C and enterobacteriaceae) was carried out in the Regional Veterinary Laboratory of Mostaganem on a total of 12 samples of pasteurized reconstituted milk. In general, the results of physicochemical analyzes revealed that the majority of the analyzed samples was presented an acceptable physicochemical quality with regard to pH, acidity, density and total dry extract. The results of microbiological analyzes showed the presence of total mesophilic aerobic germs at 30°C in all the samples tested with a low count which varies between 200 and 2550 UFC/ml; On the other hand, they showed the total absence of enterobacteriaceae including pathogenic species such as salmonella. In conclusion, the results of this study showed that the tested pasteurized milk is in accordance with national (JR 1993/69 and JR 1998/35) and international standards (AFNOR) and therefore the applied pasteurization process is effective. Reconstituted pasteurized milk must be systematically analyzed before its marketing in order to guarantee to the consumer a healthy and satisfactory quality.