A special status applies to milk produced by gentiles. Due to the concern that non-kosher substances might have been mixed into the milk in an attempt to reduce its cost, the Sages decreed that milk is kosher only if a Jew milked it from a kosher animal, or at least supervised its milking. This is known as halav Yisrael (sometimes spelled cholov Yisroel).

Certain halakhic authorities of recent generations have accepted the ruling that if there is organized governmental supervision of the dairy industry (such as the FDA in the United States), which protects consumers against fraud and deception in the agricultural industry, this guarantees that a product marketed as 100 percent cow’s milk is indeed exactly that, and therefore, it is tantamount to a certificate of kashrut. In practice, this means that although no Jew supervised the milking, it is permissible to drink the milk.

There are many halakhic authorities who do not accept this innovation of permitting milk obtained without Jewish supervision. Therefore, many of those who are strict about matters of kashrut are careful to consume only halav Yisrael.

As for products made from powdered milk, many halakhic authorities are more lenient here, as in their opinion, the entire prohibition of milk from gentiles applies only to milk that is in its original form. But those who are especially stringent will be careful even with regard to powdered milk and will only consume products whose milk ingredients are all halav Yisrael.