If one is suspected of Sabbatical year [violations], we may not purchase from him flax, even combed, but we may purchase from him thread or braided ropes.

[If] one is suspected of selling terumah as ordinary produce, we may not purchase from him even water or salt; [these are] the words of R’ Yehudah. R’ Shimon says: Whatever has a connection to terumah and maaser we may not purchase from him.