By: Rabbi Yaakov Luban
Rabbinic law requires that there be supervision during the milking process to ensure that the source of the milk is from a kosher animal. Following the opinion of many rabbinic authorities, OU policy is that in the United States, the Department of Agriculture’s regulations and controls are sufficiently stringent to ensure that only cow’s milk is sold commercially. These government requirements fulfill the Rabbinical requirement for supervision. However, some individuals are more stringent and only consume milk that was produced with full-time supervision. This is known as cholov yisroel.
All cheeses require kashrus certification, including hard cheeses (Swiss, cheddar, etc.) and soft cheeses (cottage, farmer, pot, and cream cheese). Rennet, processed from the stomachs of unweaned calves, is often used in the production of hard cheese as a curdling and coagulating agent. Kosher hard cheese is produced with microbial rennet, which is derived from kosher sources. Because hard cheese is typically made with animal rennet, the Rabbinic sages decreed that even when animal rennet is not used, a full-time supervisor must be present to guarantee the kosher integrity of the product. Hard cheese produced with kosher ingredients and a full-time supervisor is known as gevinas yisroel.Soft cheeses may contain cultures and flavors that are not kosher. Since these products are pasteurized, the kosher integrity of the equipment is an issue as well.