Tosefta על טהרות 2:1

A person gives [his produce] to an innkeeper to cook a dish for him, and she puts down the pot in front of him, and empties out its contents (see Toh. 2:1 ("מְנַעֶרֶת אֶת הַקְּדֵרָה")), even [if she is a] Gentile, there is no need for concern. (Cf. Dem. 3:5.)