If there's no smell, strange color, or interesting new growth EAT IT!

http://www.slate.com/id/2244249?yahoo=y


According to the article linked above,
expiration dates mean little to nothing,
To Sum it up:

Milk & Meats: Good up to 3-7 days past expiration dates
Produce: As long as it looks good to eat, it is good to eat.
Pasta & Rice: Good up to a year after Sell by or Best by Date.
Unopened Cookies: Past their dates have months to go before they're actually bad
Pancake Mix & Cake Mixes: have 6 more months to live
Canned Foods: Can last up to 5yrs past their expiration dates.



A tip they give though is to store your meats in the coolest part of your frig, and keep them away from your light element to make it last as long as possible.

So, Pretty much if you store your foods properly i.e. put groceries away as soon as they get home, you can go by the standards such as the ones above.