3,364. Doubtful Ritually Unclean Terumah

Terumos 14:20

If there are two baskets – one of ritually unclean terumah and the other of ritually clean secular produce – and a seah of ritually clean terumah falls into one of them, we assume that it fell into the terumah. Nevertheless, the secular produce should be eaten as roasted grain.

Terumos 14:21

If a seah of ritually unclean terumah fell into one of the baskets described in the above halacha, both are prohibited. This is because doubtful ritually unclean terumah may not be eaten, while doubtful meduma may. The reason for this is that eating ritually unclean terumah is a Biblical prohibition, while eating meduma is a rabbinic prohibition, following the principles discussed in Hilchos Maachalos Assuros (see chapter 15 there).