Related על קידושין 82:12

A Gentile that [separates] terumah -- his terumah is valid terumah (but see Ter. 1:1). In what case does this apply? [In the case of] a threshing floor, he separated terumah and gave it to a Kohen, [or separated] first tithes and gave them to a Levite [or separated] poor person's tithes and gave them to a poor person. [If his] produce is properly tithed [but] he brings his produce into his house, his produce is [considered] spoiled. An Israelite who is suspected of having brought his produce into his house, his produce [is considered] spoiled. A Samaritan is like a Gentile, the words of Rebbi. Rabban Shimon ben Gamaliel says, a Samaritan is like an Israelite.