This morning I had almost had a sour wake up. At least I thought but realized actually it was still pretty fresh. The expiration date on my skim milk was set for May 24th but I took a chance, first the sniff test, and then a quick sip, amazingly it was still fine. Which got me thinking. What do those expiration dates really mean?

According to Eat By Date, once opened, all milk lasts 4-7 days past its printed date, if refrigerated. If unopened, whole milk lasts 5-7 days, reduced-fat and skim milk last 7 days, and non-fat and lactose-free milk last 7-10 days past its printed date, if refrigerated. I like to keep my fridge on the coldest setting, which apparently also factors into longevity.

According to the FDA, if milk is left out for more than two hours, it’s considered unsafe to consume. Believe it or not, there’s even a specific location in your fridge where you should be keeping your milk. According to Jen Giambroni, Director of Communications at Real California Milk, milk should be stored at 38° to 40°F in the same container it came in, and far away from the door. When milk is stored on the refrigerator door’s shelves, it’s being exposed to warm air each time the door opens, which encourages bacterial growth. “Also, be sure to tightly close the lid to your milk cartons,” Pasieka adds. “This helps reduce accidental contamination and odors from other refrigerated products.”

Now we know. HMMMM does beer expire?