Microbial quality of buttermilk made by simultaneous adding the resin of CMC, xanthan and tragacanth during the shelf life

Butter milk is a dairy, fermented and acidic drink which is a native product of Iran. It is produced by diluting yogurt and adding water and salt to it or through direct fermentation of milk. Among all drinks in markets, butter milk enjoys a special place from the viewpoint of health-giving properties. Among demerits of butter milk, reducing its shelf life and marketability, are change of the flavor and swelling the product by the action of microorganisms. In this paper, the microbial quality of buttermilk, which is made by simultaneous adding the resin of CMC, xanthan and tragacanth, was analyzed during the shelf life. Microbial tests of samples were conducted according to the Iran national standards in order to determine and count the coliforms, Escherichia coli, Staphylococcus aureus, and fungi. The results revealed that adding resin to samples of butter milk increases the stability of the microbial load, but has no effect on pH and organoleptic properties. No contamination to coliforms, Escherichia coli, and Staphylococcus aureus was seen in the samples. The rate of contamination to fungi was in the range of Iran national standard. According to the results, serious actions are necessary to control the fungal contamination of dairy products without using preservatives.