An Essential Agent
‘Set In The Skin Of The Rennet Of Nevelah’
(Avoda Zara 35a)
Our daf is related to a sugya in Chullin (116a) that discusses the process of curdling cheese. But first let us quickly review one of the rules of basar b’chalav – the prohibition of cooking milk and meat. Milk that is cooked in a pot used for meat is forbidden if it absorbs the flavor of meat from the pot. If it did not absorb any of the flavor, it is permitted because the minuscule amount of meat is nullified. R. Yochanan (Chullin 97a) says that one way of ascertaining whether the taste of the meat is present in the milk is giving the milk to a kepeila – a gentile chef – to taste.
The general rule regarding bitul (nullification) is that an item less than of 1/60th of the total is nullified. Thus, if there is less than 1/60th meat (juice) to milk in a mixture, the milk is kosher.
The Expert Rules
The Mishnah (Chullin 116a) states that if one curdled cheese in the stomach of an animal, the cheese is forbidden if it absorbed some of the taste of the animal’s stomach. If, however, we are able to ascertain through the services of a gentile chef that it did not absorb any of the flavor, the cheese is permitted.
Non-Kosher Source
Shmuel rules that the cheese produced by a gentile is prohibited because it is commonly curdled in the stomach of a nevelah (an animal that was not kosher slaughtered). Therefore, it is forbidden due to the possibility of nevelah content.
The Rishonim ask: Why is gevinas akum (cheese produced by a gentile) always forbidden? Let us give it to an expert gentile chef to test.
What Is Common
The Ramban (novella ad. loc.) answers that since it is common for cheese to acquire flavor from the nevelah stomach, the sages banned all gevinas akum, even if a kpeila determines that no taste was absorbed. (They were concerned about all situations and did not wish to weaken their ban.)
Beyond Flavor
The Ri Migash (cited by Ramban and Ran, folio, 13 in the pages of the Rif) argues that even if the cheese did not absorb the flavor of the nevelah, it is nevertheless forbidden because the rennet the milk absorbs from the stomach is necessary to the production of the cheese, and something that is essential to a food’s production is never nullified, even if no flavor is imparted.