Chalav Yisrael, also pronounced cholov Yisroel, refers to kosher milk whose milking was observed by an observant Jew. The halakha of chalav Yisrael, which originates in the Mishnah and Talmud, was instituted to ensure that no non-Jew would mix milk of a non-kosher animal with the kosher milk. Today, many kosher-keeping Jews rely on the ruling of Rav Moshe Feinstein, who argues that since countries such as the United States have strict laws against mixing milks, it can be assumed that the milk is kosher. Background According to Jewish law (halakha), milk is only considered kosher if it derives from a kosher species of animal—in regards to milk, this primarily covers cows, goats, and sheep. Milk from a non-kosher species, such as horses and camels, is inherently non-kosher. Institution of chalav Yisrael requirement By the time of the rabbis of the Mishnah (Tannaim), Chazal (the Jewish sages) instituted an injunction against any milk whose milking was not done by, or under the supervision of, a Torah-observant Israelite. The prohibition, which is listed in the Mishnah tractate titled Avodah Zarah, allows for benefit to be derived from such milk, while drinking it is forbidden out of fear that a non-kosher animal's milk was mixed into the kosher milk. Milk milked by a non-Jew came to be known as "chalav akum," which literally translates directly to "milk of a non-Jew," and milk that was properly milked in accordance with the law is known as "chalav Yisrael, literally "Jewish milk." Traditional Ashkenazi pronunciation of the Hebrew is "cholov Yisroel." This concept was later carried on to Avodah Zarah section in the Talmud during the Amoraic age. Located on page 35b, the discussion regarding chalav Yisrael milk debates whether or not it is halakhically necessary for the stringency as there are factors that give away if milk came from a non-kosher animal. However, all of the possible permissibilities have issues themselves, leading the Talmud to make no change to the law. Chalav Yisrael milk was first codified in Maimonides's Mishneh Torah, which agrees that the prohibition is logical. The Shulchan Aruch, Rabbi Joseph Karo's widely accepted code of halakha, was the next, doing so in its Yoreh De'ah section. Modern chalav Yisrael milk is overseen by a mashgiach, or kosher supervisor, who is required to be present at the beginning of the milking but does not need to be there constantly for the whole