The Shelf Life Advice Quick Reference Guide has answers about refrigerated unopened and opened foods. To receive your copy, type your email address in the box below and click "Sign Up".

How long can I keep refrigerated leftovers?

Leftover Food scientist Susan Brewer offers the following advice: the amount of time which leftovers are safe and/or of good quality depends on the leftovers.


Mixed dishes which contain (cooked) animal products (such as meat, milk, and eggs) tend to have the shortest shelf life both for quality and safety reasons. They may have originally had pathogenic bacteria associated with them. If cooking didn’t kill every single one, the bacteria can grow (slowly), making the product unsafe. Three days is the standard length of time recommended for these products.

Some Like It Hot, Some Like It Cold—Either Way, Here’s How to Keep Home-made School Lunches Safe and Tasty

Lunch BoxDiane laughs as she recalls carrying a peanut butter and jelly sandwich to school every day for some eight years:  “It was the only meal my mother considered safe to consume after being unrefrigerated all morning.” Today, we know that safety doesn’t require such monotony.  However, the challenge remains—how to pack nutritious, delicious meals that will remain uncontaminated even if they spend all morning on a coatroom floor.


Perishable foods (those that need to be kept hot or cold) must not be left in what food scientists call the “danger zone” (40°-140°F; 4°-60°C)  for more than two hours. Bacteria and other pathogens that can contaminate foods and cause illness grow rapidly in that temperature range.  Children’s lunches, if left unrefrigerated for about four hours, must contain only shelf-stable items, or parents must learn a few techniques for keeping hot food hot and cold food cold. (These tips will also come in handy when adults prepare their own portable lunches.)

FAQ about Pasta Sauce—How Long Dare I Keep the Open Jar?

Pasta SaucePasta sauce is perhaps the quintessential “How long will it keep?” product.  If you’re cooking for a small household—1-3 diners—you’re not likely to polish off a large jar at one meal, and it’s hard to find a small jar on store shelves. Therefore, you may regularly find yourself left with half a jar. But how soon are you going to want pasta again?  You put the remainder in your fridge, and, before you know it, ten days have passed. Now what?  Is it still good?  Would it be obvious if it weren't?  Can pasta sauce turn dangerous?  Probably not, you think. On the other hand, it probably won’t taste too good anymore, so maybe it should be tossed. But, then again, it would be a pity to waste a half jar.  And round and round you go.

Nibbling Our Way Around the IFT Food Expo

I'm collecting samples--of  WOWBUTTER--( which looks like peanut butter but isn't), of popped sorghum (which looks like popcorn, but  isn't), and of a pollipop look-alike that puns the message "We're suckers for colors."  Where am I?  Today is July 18th.  I'm attending the annual meeting (aka convention) of the Institute of Food Technologists (IFT).  


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