Mastitis is one of the most important and costly diseases in the world,and elevation of somatic cell counts is a major food safety criterion in the international trade of milk and milk products and it is an indicator of hygienic conditions of milk production.The annual costs of mastitis in the world have been estimated to be approximately 35 billion US dollar.Importance and economic losses of mastitis:Economic losses are due to costs of reduced production,decreased sale value,discarded abnormal milk,early replacement of affected cows,treatment,and veterinary services and increased labor costs but there are other costs that their effects are unknown such as reduction of cheese yield,shelf life of products and consumer acceptance.