Many people are saying the OP should have donated the expired food - the point is, you can't.
As for being sad she was too late, sure, but how many of us haven't found expired food in our pantry? I'm pretty organized, but I know I have.
Why not? I work in the nonprofit sector, and have volunteered several times this year with the local food bank. They do take and distribute expired food. Every type of food has a different "post sell by date" that's acceptable- ie canned veggies might be 12 months, canned meat 18, etc. They are, at least in my state, allowed to distribute expired food if it's still acceptable.
However, it would be a reasonable price for those who don't have the time or skills to bargain/coupon shop.
I hate to waste food too, but the safety of my family is far more important to me. I just don't take chances with food that is questionable. I cannot wrap my brain around the fact that you put food on store shelves. Do you "donate" it to the store (i.e. put it on a shelf when nobody is looking?) or do you return it and get a refund?