Dairy products are potentially considered as important sources of enteric viruses transmission. Currently, there is a lack of appropriate methods for sampling and study of enteric viruses in food products. Therefore, the design of modeling experiments can lead to accurate and precise estimation of viral pathogenic agents. To achieve this aim, the effects of thermal treatment of raw milk, traditional butter storage time, and the bacteriophage spiked levels on survival of the male-specific MS2 coliphage in traditional butter were studied. MS2 spiking concentrations in three levels of 102, 104, and 106 pfu/ml, traditional butter storage time in four levels (after 1, 2, 3, and 4 weeks), and pasteurization process (858C for 30 min) of raw milk were chosen as treatments. MS2 coliphage survival, as well as chemical and microbial tests were conducted on pasteurized and unpasteurized butter. The results revealed that pasteurization of raw milk used in the production process of traditional butter led to the reduction of MS2 coliphage survival. Also, acidity and pH affected MS2 bacteriophage recovery in a way that increase in acidity and reduction of pH caused a decrease in bacteriophage recovery. pH was measured at 1-week intervals until 4 weeks of storage; the highest pH was indicated in the butter samples after the first week, and the lowest pH was observed in the Doogh samples after the fourth week. Therefore, we ascribed the lowest and highest MS2 recovery rates to butter and Doogh, respectively.

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