Evaluation of the Chemical and Microbial Characteristics of Pasteurized Yoghurt Drink and Milk Products in Zanjan Province During the Years of 2012 to 2014

Dairy products have specific roles in human nutrition due to the high biological values concerned with proteins. The aim of the present study is to evaluate the chemical and microbial characteristics of pasteurized yoghurt drink and milk products that were produced in Zanjan province between the years of 2012 and 2014.
Totally 101 samples of pasteurized milk and 63 samples of pasteurized yoghurt drink were analysed. Sampling and chemical and microbial tests were carried out according to the Iranian National Standard.
According to our finding out of thetotal samples of pasteurized milk, in terms of acidity, one sample (0.99%), in terms of milks solid not fat contents, 10 samples (9.9%) and in terms of density 9 samples (8.91%) were not according to the standard. Microbial contaminations were not observed in the samples studied. The yoghurt drink samples were according to standard in terms of acidity and pH and only two samples had solid not fat contents more than the figure defined by the Iranian National Standard. The microbial examination of the yoghurt drink indicated that one sample was contaminated with coliform and five samples showed the presence of mold and yeast.
Our findings have indicated that the microbiological loads of pasteurized yoghurt drinks and milk produced in Zanjan province are according to the values defined by Iranian National Standard, however continues supervision and controlling is required for both chemical and microbiological values of these products.