well, who pays for the food? do all the same parents always buy the food, and are they the ones taking it home?

If you have a monthly newsletter, you could put a blurb in it. There are lots of ways you could tactfully change policy.. share more about who pays for it and stuff, and I will give you some suggestions on what to say, and how!

By majority parents & board members taking home the unopened food for family use is not the norm unless it's perishable. How should this subject be approached? It's been a long silent tradition - not sure this is the perception we need.

we do a few different things:

1-if it is open then we usually give it away to the last few people to leave.
2-Unopen usually ends up in our storage closet, it is easy to look at a date and see when it expires, we have events each month so we use it the next month.
3-if it is unopen and we have no use right away we usually donate to another cause that is happening in our school.

Our Treas.'s hubby sits on the board at a shelter, so any cooked food we have left over (if it is enough to be worth it) goes to them. If it is something that will keep, we save it. If it is something like unopened chips, juice, etc. that will not keep until our next event, we try to make some use of it at school~snacks for field trips or something like that. If it was just something like a tray of cupcakes or whatever, we would send them home w/someone.

Unopened stuff that will stay till the next event (with expiring) definitely is left till the next event. Prepared dishes that are taken are provided for a donation to the PTO...in some cases we're talking complete lasagnas etc....d

We do basically the same thing; leaving in the teachers lounge or giving to the classrooms.

For us, saving it for the next function isn't great - can be forgotten about.