Commentary for Chullin 8:5

קיבה – congealed milk that is within the maw.

Introduction Today’s mishnah deals with the milk that is found inside the stomach of an animal. This sour milk contains enzymes that were used to curdle milk and make cheese. Similarly, the lining of the stomach was also used in this process.

נכרי ושל נבלה – this is what he said, the maw [of the stomach] slaughtered by a heathen is carrion and this is prohibited.

The [milk in the] stomach [of an animal] of a Gentile or [in the stomach of] a nevelah is forbidden. This milk is prohibited because the animal is prohibited.

המעמיד – milk.

If a man curdled milk with the skin of the stomach of an animal that was validly slaughtered and it imparted its flavor [to the milk] it is forbidden. The skin of the stomach of an animal is considered to be meat. Therefore, if a meaty taste is imparted to the cheese then the cheese is considered to be meat mixed with milk and it is forbidden. If there is no taste of the meat, then the cheese is permitted.

בעור של קיבה – which is meat.

The [milk in the] stomach of a validly slaughtered animal which had suckled from a terefah animal is forbidden. The [milk in the] stomach of a terefah animal which had suckled from a kosher animal is permitted, because the milk is collected inside. The milk in the stomach of an animal is considered to have come from the mother from whom the animal suckled. Thus if milk is found in the stomach of an animal that was validly slaughtered, but it is known that the milk came from a terefah (an animal that cannot be eaten because it will die from a defect/wound) then the milk is prohibited. In contrast, if the slaughtered animal was a terefah, but the animal from which it suckled was valid, then the milk is permitted. We should note that this mishnah has many ramifications for later halakhah, specifically with regard to the issue of making cheese. There are various opinions among medieval commentators with regard to whether the milk found in the stomach of an animal, which is called rennet, can be used to make cheese if it comes from a non-kosher animal. However, this is not the place to expand upon such an issue. For more information, you might want to look on the Rabbinical Assembly’s website for a teshuvah concerning the use of rennet in making cheese.

אם יש בה – to impart a flavor with milk, it is prohibited, and if not, it is permitted, and even though he curdles [milk] since the flesh itself is of something permitted, and its prohibition is not other than on account of another matter that was combined with it, and we don’t say in this that everything follows after the curdling. But if he curdled the cheese in the flesh of the maw of a carrion, even if it doesn’t have what to impart a flavor in the milk, it is prohibited because the curdling is prohibited, and its prohibition is on account of itself. Therefore, [the Rabbis] prohibited the heathen cheeses because they curdle it in the skin of the maw of a carrion. But the rennet itself which is the congealed milk that is within the maw. We wind up that there isn’t a prohibition at all, that it is a mere secretion (see Tractate Hullin 116b). Maimonides wrote this, but Rashi wrote that the milk that is found congealed in the skin of the maw that we salt it in its hide. I would be wont to permit it until this point, for as long as no other milk is placed in it. But I would err in this for I would think as we state [in Talmud Avodah Zarah 29b -see Mishnah Avodah Zarah, Chapter 2, Mishnah 5) regarding the rennet from a whole [burnt] offering of a Kohen who is not squeamish sucks it out raw, we learn from it that it is a mere secretion and it is not forbidden. But it is not complete milk, as it is taught in our Mishnah that it is fit, when one sucked it from an animal with an organic inflicted disease, it is prohibited, we learn from it that it is milk. And the rennet of a burnt offering which is permitted, because it is not part of its body but rather that which is quaffed from its mother, and it is an entrance into the bowels like it is placed into a dish and it is permitted.