Avodah Zarah 69 - The Saga of Mouse Continued
Assuming that the flavor that a mouse gives to beer is beneficial, what is the law if it falls into vinegar? There was such a case in Rav Kahana's household, and he prohibited it. Do we see from here that the mouse indeed gives a beneficial flavor, and that's why he prohibited it? - No, but in that case small pieces of the mouse remained in vinegar, and since one gets lashes for eating a smaller piece of a mouse than other non-kosher foods, he prohibited it for this reason.
If an idol worshipper was helping a Jew to transport jugs of wine and the Jew had to leave for some time, then the status of the wine depends on what did the Jew say. If he traveled up to a mile but did not inform the idol worshipper, then the wine is permitted. If, however, he told that he would be going far enough for the idol worshipper to bore a hole, patch it with clay, and for clay to have dried up, the wine is forbidden. Similar guidelines apply to an idol worshipper left on a boat, in a store, or at the table. Note that the final law does not agree with this level of suspicion.
Art: Frederick Childe Hassam - Carriage on Rue Bonaparte