3,463. Entrusting Produce to a Non-Jewish Custodian

Hilchos Maaser 11:15

If produce is left with a non-Jew for safekeeping, it is treated as if it were the non-Jew's produce; this is because we assume that he may have exchanged it with his own produce. Therefore, if the labor to complete the produce was not yet performed and the Jew performed those tasks after reclaiming his produce, he must take tithes from it as has already been discussed. If the produce that he left was untithed and its labor was completed, he must take tithes because maybe the non-Jewish custodian didn’t exchange it. Because of this, the Rambam opines, the tithes that he takes are doubtful. If he entrusted regular produce that was already tithed, he need not separate anything because, even if the non-Jew exchanged it, it’s exempt. As we previously discussed regarding terumah, the laws of tithes apply to “your grain,” not to the grain of a non-Jew.

Hilchos Maaser 12:1

If someone buys produce from one who is not trusted regarding tithes and the buyer forgot to tithe it before Shabbos or yom tov – days on which tithes may not be taken – he may ask the seller their status. If the seller tells him that the produce was tithed, he may rely on him for that Shabbos. Similarly, if a third party who is not trusted regarding tithes says that it was tithed, the buyer may eat it that Shabbos based on his word. This is the case even if he has other produce of the same kind that was already tithed. The reason for this leniency is because we assume that the awe of Shabbos impacts even the unlearned so they will not be inclined to break the law on that day.