כִּ֤י תָבֹא֙ בְּכֶ֣רֶם רֵעֶ֔ךָ וְאָכַלְתָּ֧ עֲנָבִ֛ים כְּנַפְשְׁךָ֖ שָׂבְעֶ֑ךָ וְאֶֽל־כֶּלְיְךָ֖ לֹ֥א תִתֵּֽן׃ (ס)
When thou comest into thy neighbour’s vineyard, then thou mayest eat grapes until thou have enough at thine own pleasure; but thou shalt not put any in thy vessel.
Tosefta Maasrot
Workers that were hoeing among the fig trees or picking dates or harvesting olives -- they may eat and are exempt, since the Torah gave them permission (see Deut. 23:25-26). [But] they may not dip [the figs or olives] in salt and eat unless the homeowner gave them permission, and they may not eat them with bread unless the the homeowner gave them permission.