Résumé:
In Algeria yogurt is fermented dairy product most often consumed (because of that richness in nutritional substances, so in its fresh state or after drying to extend this shelf life.
This work has allowed us to study the hygienic and microbiological quality of five samples of yogurt consumed by the Algerian population at the microbiology laboratory (University Abdelhamid Ibn Badis Mostaganem).
From 25 samples, we isolated and purified isolates. Indeed, the bacteriological quality of the fermented milk can be assessed by counting of the total aerobic mesophilic flora. In the latter we counted exhaustively any germs that may be present in samples of milk for analysis, namely the Enterobacteria, Staphylococcus, lactic acid bacteria, yeasts and molds.
Identification of strains was established by macroscopic and microscopic study, the physiological and biochemical characterization tells us the fermentation type and the study of growth at 30 ° C, 45 ° C. The technological power of the isolates was demonstrated on specific areas such as the degradation of arginin.
The results obtained are as follows:
-The Average value of 3.96 FMAT is 3,96 107 UFC /ml. In addition, the average load of lactic acid bacteria in the samples analyzed is 3,08.107 UFC / ml, absence of the photogenic bacteria is Enterobacteria and Staphylococcus.
-We Note dominance of lactic acid bacteria in all samples studied. otherwise, we noted a germ index of fecal contamination and pathogens like Staphylococcus.
In conclusion, the studied samples of yogurt are good hygienic quality and meet the microbiological standards set by the regulations
