Eruvin 80 - Food in an alley | Talmud Illuminated

In addition to collecting food from all residents in each courtyard, the different courtyards in an alley have to collect food for the common "alley eruv," in order to allow carrying on Shabbat between courtyards. Practically, however, it may be too burdensome, so instead one can act as follows: he takes a barrel of his own food and declares, "Let this belong to all the residents of the alley." The declaration alone won't suffice though, since in every transaction there must be a recipient. Therefore, he asks someone independent of him, even a servant, but not a dependent child, to acquire the barrel on their behalf.

How much food does there have to be? Even the amount of two meals for one person is enough, since this is a significant amount of food, and every one of them can eat it. This amount of food is needed only at the beginning of Shabbat. Later on, if some of it was eaten or lost, it does not matter, as long as a little bit is still extant. Why this leniency? The whole purpose of the eruv is to remind children that carrying in the street on Shabbat is prohibited, as evidenced by the elaborate eruv procedure. Once this goal has been accomplished, some of the food can be eaten.

Art: Still life with food by Mary Ellen Best (1809-1891)