One who accepts upon himself to be a chaver does not sell to an am haaretz wet or dry [food], does not buy from him wet [food], is not hosted by an am haaretz, and does not host him in his clothes. R’ Yehudah says: Also, he should not raise small domesticated animals, he should not overindulge in vows and frivolity, he should not render himself tamei [through contact] with dead bodies, and he should serve in the House of Study. They said to him: These things are not included.

[Regarding] bakers, the Sages required them to separate only [a quantity] sufficient for terumas maaser and challah. Shopkeepers are not permitted to sell demai. All who sell with a large measure are permitted to sell demai. These are those who sell with a large measure: [those] such as grain wholesalers and sellers of grain.

R’ Meir says: That which is usually measured with a large [measure] which one meas-ured with a small [measure] — the small [measure] is subordinate to the large [one]. That which is usually measured with a small [measure] which one measured with a large [measure] — the large [measure] is subordinate to the small [one]. What is a large measure? For dry [food], three kabin; for liquids, [the value of] a dinar. R’ Yose says: Baskets of figs, baskets of grapes, and boxes of vegetables — when-ever one sells them by estimation, he is exempt [from the demai tithing requirement].

We may feed paupers demai, and traveling soldiers demai. Rabban Gamliel would feed his workers demai. [Regarding] charity officials, Beis Shammai says: They [must] give the tithed [food] to [a pauper] who does not tithe, and the untithed [food] to one who tithes. Thus, each person eats fixed [food]. But the Sages say: They collect indiscriminately and they distribute indiscriminately, and whoever wishes to fix [the food] should fix [it].