Shailah of the Week

How Is “Chalav Stam” Permitted?

Rabbi Eli Gersten January 6, 2021

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Written by Rabbis Eli Gersten, Yaakov Luban and Moshe Zywica of the Orthodox Union


Chazal prohibited all milk unless its production was witnessed by a Yisrael, who must ensure that the milk is only from kosher species (Avodah Zarah 35b, Yoreh Deah 115:1).



However, there is a halachic principle of anan sahadei (virtual witnesses), which means that if we know that something is occurring, our clear knowledge of this occurrence is the halachic equivalent of being witnesses to it. The heter of chalav stam, as formulated by Rav Moshe Feinstein (Iggerot Moshe YD 1:47-49), is predicated upon our clear knowledge that the government is properly regulating the dairy industry, including the government’s ensuring that milk from non-kosher species is not present. We know that the milk suppliers adhere to the dairy regulations because the suppliers are apprehensive of being penalized for violation and of their reputations being ruined through noncompliance. Halachah considers our clear knowledge that the milk is not from non-kosher species to be the equivalent of witnessing. Hence, the requirement that a Yisrael must witness all milking is fulfilled, as we are all deemed halachic witnesses to the milk’s production.


The heter of chalav stam only pertains to countries which have adequate dairy regulations. The OU’s poskim have ruled that European Union nations and other countries with well-enforced dairy regulations qualify for the heter of chalav stam. In countries where such regulations are lacking or are poorly enforced, milk remains prohibited as chalav akum and requires on-site kashrus supervision in order to be permissible.