Microbiological quality of pasteurized milk on expiration date in Tehran

As different kinds of milk and milk products are imported from other cites to Tehran, it is necessary to have further control on these products in order to make sure that they have acceptable qualities. In this study, microbial quality of pasteurized milk collected from Fruit and Vegetables markets in Tehran was evaluated. Microbiological quality of 103 pasteurized milk samplescollected from Fruit and Vegetables Markets in Tehran was evaluated by enumeration of aerobic mesophilic microorganisms, coliforms and detection of Escherichia coli according to Iran's National Standards on expiration date. The result's statistical analysis was performed using SPSS software version 17 and P values less than 0.05 were considered significant. Collected samples were from 13 different brands. Coliforms, Escherichia coli and aerobic mesophilic microorganisms were in accordance with Iran’s National Standard’s limits in 78.6 percent (<10 CFU ml-1), 92/9 percent (absence of Escherichia coli) and 40.8 percent (<7.5× 104 CFU ml-1) of the studied samples, respectively. Only 6.8% of the studied samples had unacceptable levels of all three microorganisms. According to packaging type (bottle and bag), total aerobic mesophilic microorganisms count, coliforms count and Escherichia coli contamination were not statistically significant. Although coliforms count mean was higher than the standard limits, coliforms count had an acceptable level in 78.6 percent of the samples. The results of the present study confirmed the partial satisfactory quality of pasteurized milk packages in Tehran.