Contrôle de qualité microbiologique et physicochimique du lait de vache cru et pasteurisé dans la wilaya de Ghardaïa

Abstract

In order to evaluate the quality of cow's milk considered a the most exploited in dairy production for human consumption in the region of Ghardaïa, seven dairy and derived production units were chosen to carry out sampling under experimental conditions Two samples per dairy, one for raw mil k of collection and the other for pasteurized milk packaged in bag . The germs foreseen by the Algerian national standard were researched, physico- chemical analyzes were carried out in parallel. The results obtained from the raw and pasteurized milk of sev en units showed different levels of protein, fat and lactose from one raw milk to another and from one pasteurized milk to another with a pH value slightly acid and a titratable acidity of the order of 16D ° for the majority of the samples. Both types of m ilk were devoid of pathogenic germs with a major risk to consumer health such as (Staphylococcus aureus, Clostridium perfringens ). The total aerobic mesophilic flora rate was variable and significant for the majority of samples of raw milk; it was between 2.7.10 4

and 2.10 8 CFU / mL, of which only two meet the standards. In pasteurized milk this microbial load was decreased after pasteurization, but it was exceeded the norm. Fecal coliforms, absent in the majority (6/7) of pasteurized milks, were more numerous in the mixing milk taken under the usual hygiene conditions of the farm and with a significant load ranging from 0,5.10 2 and 9.10 6 CFU / mL. Faecal streptococci were absent in 0.1 mL for the majority of raw milk samples (5/7).