Way too many variables to put a Use By or Die date on food. Assuming the Grocery store handled the product right...How quick did You get it in the refer. Are you 30 minutes from the store or 2 hours? Is your refer running properly at 38° or less? Has the product be opened? A cryovac sealed cut of meat, pork tender, can last 2 weeks past the Sell By and 7-10 days past Use By. A trimmed pork steak of a foam tray has 3 days past sell by before it gets funky. Is the refer qrequently opened and the kids stare in for 20 minutes then whine there is nothing to eat. Or, is the refer only opened a short time and perishable items are on the back of the bottom shelf, coldest place? An unopened gallon of milk will easily last a week past the Use By Date. But, that milk you chug out of the bottle, when no one looking, has 3 days, maybe.
Best plan is to Forget the Dates! Don't buy more perisable foods than you will use in 7 days. If there is a crazy sale on Trimmed and wrapped Butts, freeze what you won't use in 3 days. Cryovac Butts, you got 7-10 days to use or freeze...JJ