Commentary for Terumot 10:1

בטל שנתנו לתוך עדשים – [of unconsecrated produce] and the same law applies [regarding] an onion of heave-offering that was placed within lentils [there is an error of the copier here, and as one needs to say: ‘onion that was placed in the midst of lentils,” with an onion of heave-offering that was placed within lentils [[of unconsecrated produce]], and the same law applies to onion of unconsecrated produce that was placed into lentils of unconsecrated produce, and we are speaking as for example, that he placed it in the lentils after it became ripe and its water had gone out from it, for then, the onion when it is whole discharges on the lentils but does not absorb from them. But if the onion had been ripened with the lentils, it is obvious, that it gives and absorbs taste, even when it is whole.

Introduction This chapter deals with terumah that has been placed together in a dish with hullin after it has been cooked, and with whether the whole mixture has to be treated like terumah.

בנותן טעם – that the Kohen tastes them, that it is permitted in unconsecrated produce and in Terumah/heave offering, if it has the taste of heave-offering, everything is prohibited to foreigners (i.e., non-Kohanim), and if not, it is all unconsecrated produce as it was.

An onion [of terumah] was placed into lentils:
If the onion was whole, it is permissible; In this mishnah one of the two characters, the onion or the lentils, is terumah and the other is hullin. If the onion is whole it won’t impart its taste to the lentils, nor will the lentils impart their taste to the onion. Lentils don’t have a lot of taste nor do they easily take on the taste of things cooked with them. Since one cannot taste the other both retain their former status and whichever one was hullin is still permitted to the non-priest.

ושאר כל תבשיל – as, for example, garlic and purret (i.e., leek with a head), in a similar manner.

But if [the onion] had been cut up, [it is forbidden if it] imparts a flavor. If the onion had been cut up then it will impart its taste to the lentils if there is sufficient quantity of onion, and if there is sufficient quantity of lentils, they will impart their taste to the cut-up onion. Therefore, if the terumah food imparts its taste to the non-terumah food, the non-terumah food must be treated like terumah and it can be eaten only by a priest. The priest should taste the non-terumah food and if it has the taste of the terumah food, then only the priest can keep eating it.

מתיר בצחנה – if he placed onion of heave offering in a small fish preserved in brine, which are small fish that are pickled in brine, he takes the onion and the small fish preserved in brine it is permitted, as long as the onion will be whole and it is not dissolved and is not combined with the small fish preserved in brine, for the onion that is placed in side it rather than to transfer the froth of the fish and not in order to give it a taste. But the Halakha is not according to Rabbi Yehuda.

In the case of other dishes, whether the onion is whole or cut up [it is forbidden] if it imparts a flavor. The previous was true with regard to lentils which don’t have a strong taste and are not so susceptible to the taste of the onion. When it comes to other dishes, it doesn’t matter whether the onion was cut up or not, the dish is prohibited if the onion can be tasted.

Rabbi Judah permits it in the case of mashed fish, because it is used only to remove the unpleasant flavor. Rabbi Judah says that if a terumah onion was put into a mixture of mashed up fish, a mixture which has a bad smell, the fish remain permitted to a non-priest because they were put there not to give taste but to get rid of the bad smell.