נותן טעם לפגם - Contributing a Negative Taste

(1) Any forbidden thing with a rancid taste (like rotten pork) cannot render a mixture prohibited. And even a case where the item's taste is not rancid by itself, but rather tasty and enhancing, but if it is rancid in this mixture, the mixture is permitted. Rema: However, important things, like a biryah (a complete organism, like an insect) and other similar things, if they do not themselves have a rancid taste, even if they make the mixture taste worse, they are not nullified, even in a thousand times their volume.

(2) ...And there is he who says that this is really when the forbidden item mixed in is small compared to much of the permissible item, but if the forbidden item is much within a small amount of permissible item, and even when it is half and half, we do not say that “giving a rancid taste is permissible” until it makes [the mixture] totally rancid [such] that it is not fit as human food.

(5) Any pot which is not bat yoma ("from this day") is considered to be such [that] its taste is detrimental and it is does not make forbidden food cooked in it. And it is called "bat yoma" if it has been used within the previous 24 hours. Once 24 hours have passed, it is not called bat yoma. And if one cooked in it when it was not bat yoma, the cooked food is permissible for this will be a “giving a detrimental flavor”.