פירוש על עבודה זרה 117:11

In principle, a non-Jew can carry grapes to the winepress because they are not yet wine. But R. Kahana says we should not let them do so just to stay away from any chance of them coming to touch the wine.

The baraita clearly allows grapes carried by non-Jews to the winepress. Even if some liquid comes out of the grapes, the grapes do not become yayin nesekh.