3,482. Produce That Is Either Definitely Untithed or Doubtfully Tithed

Hilchos Maaser 13:20

Let’s say that everyone in a city sells produce that is definitely untithed and one person sells produce that is doubtfully tithed. If one buys produce from a seller and he doesn’t know who it is, he should rectify the produce as follows: He first takes terumah and terumas maaser and gives it to a kohein, after which he takes second tithe, which is considered the second tithe of demai.

Hilchos Maaser 13:21

The same is true if a person has two vessels – one containing definitely untithed produce and one containing tithed produce. If one of these vessels is lost, he must take terumah and terumas maaser from the other and give it to any kohein he chooses. He then takes second tithe and it’s considered the second tithe of demai.