Whether the package says “best by,” “use by,” or even “expires on,” food doesn’t instantly become poisonous once it hits its printed date. Many products are perfectly fine long after the date passes, and many only gradually decline in quality as they age. Some particular types of foods, however, may spoil or become increasingly unsafe if you wait too long. Knowing the difference isn’t always easy and consumers are justifiably confused by date labels. It’s no surprise that the nonprofit ReFED estimates that people threw away about 6.5 million tons of food in 2022 due to uncertainty over those little pixelated numbers.
ReFED and others are working on standardizing date labels to minimize needless waste. In the meantime, here’s a guide to assessing the shelf lives of various types of food. Most of the sections below contain links to EatOrToss articles that go into more depth. All of the articles in our Behind the Date Label series are informed by conversations with scientists, food testing labs, food companies, and government agencies as well as reviews of university and government publications.
First, keep in mind that in the United States, date labels are generally not federally regulated.
with the exception of baby formula, the federal government does not require date labels. Some states have laws, but they aren’t necessarily based on food safety science (for more on how date labels are created and efforts to standardize them, check out this post). On foods more susceptible to microbial growth, food companies may conduct research to set a “use by” date; but you may still see “use by” on foods that only suffer quality problems as they age.
How to evaluate shelf-stable foods after their “best by” dates
Shelf stable foods bearing a “best by” date typically develop quality and not safety issues as they age. This includes foods like crackers, cookies, canned goods, pasta, and peanut butter. This article goes into more detail, including clues on which foods are more likely to go rancid or stale faster.
Are dairy products OK after their “best by” “use by” or “sell by” dates?
Dairy products vary widely in their shelf lives and susceptibility to spoilage. This article explores milk, cheeses, yogurt and other dairy foods.
How to evaluate eggs past their date
According to the United States Department of Agriculture, you can safely store eggs in the fridge for three to five weeks after you bring them home from the store. The agency also recommends making sure your fridge is 40 degrees Fahrenheit or less to keep your food safer and longer lasting.
And honestly, there’s nothing about hitting that five-week mark that makes eggs suddenly unsafe. Just keep in mind that, over time, eggs’ yolks and whites thin out (for a graphic and explanation of why, check out this post). Shelled eggs are quite robust, but those changes do weaken their defenses, making it easier for bacteria to get in. If an egg seems fine, but you’re on the fence, you could cook it thoroughly to mitigate risk.
If your egg looks odd and you’re not sure if it’s still good, check out EatOrToss’s Egg Library.
If a food says “use within X days of opening,” can you eat it for longer?
Often, yes. But assess it first.
Once a sealed package or container is opened, its contents can be contaminated by mold spores, bacteria or anything else in the environment. The food also loses some protection from its packaging. For example, many products are packed at bacteria-zapping high temperatures and the “air” in the package is calibrated with specialized ratios of carbon dioxide, oxygen and nitrogen designed designed to keep the food fresh for longer.
Depending on the product (could it easily support microbial growth? is it very dry? very acidic? does it have ingredients that might prevent such growth?), it may easily be fine after that “use within” window, or it could start to decline. You might try the sniff test and consider your own tolerance for risk. This article has more detail.
What does a “use by” date really mean?
“Use by” dates are more complicated than “best by” dates because they are more likely, though not necessarily, tied to safety or at least a high susceptibility to spoilage.
The voluntary date labeling standard that many manufacturers follow says the phrase “use by” belongs on products where a food safety concern or significant deterioration of the product will occur after that date. Sounds reasonable, but in practice, it gets tricky.
If you’re debating eating a product past its “use by” date, first consider what kind of product it is. Since the standard referenced above is voluntary, it’s not universally deployed. I’ve seen “use by” on plenty of shelf stable products, like packaged cookies (with their dry texture and high sugar and salt concentrations, cookies are unlikely to succumb to microbial growth). In that case, the manufacturer probably doesn’t have reason to believe the product will be unsafe soon after the date.
But if you’re looking at a perishable product that requires refrigeration, like a ready-to-eat sandwich or pre-cut melon, you’ll want to pay more attention to that date, especially if the food will be eaten cold, without a heating step that would hopefully zap bacteria. Microbial growth, which could make you sick or simply make your food taste gross, are potential concerns in these vulnerable foods.
The articles below explore the safety and risks of some more perishable foods after their “use by,” “sell by” or “best by” dates. These are foods that can more easily support microbial growth. They are often raw, high moisture, low acid and contain minimal salt or sugar.
- Raw meat
- Deli meats
- Pre-chopped produce (chopping produce significantly shortens its shelf life; while whole fruits and vegetables are often fine outside the fridge, chopped ones must be kept cool)
- Salad greens
- Dairy products
What about “sell by” dates? Or expiration dates?
Many products bear “sell by” dates and provide no direct guidance to the consumer. While the “sell by” dates are designed to help stores manage inventory, they are not consumer-oriented safety dates. That said, I’ve often seen “sell by” listed on some of the most perishable foods around, like milk, raw meat, and in-store-sliced deli meats, likely because staff members need to turn those items over quickly. Also worth noting, for food safety reasons, the FDA Food Code specifies that certain refrigerated foods prepped in-store should be sold or discarded within seven days.
And, of course, some manufacturers still use phrases like “expires on” or simply “exp.” followed by a date. I haven’t noticed any particular pattern, but I do suspect we’ll be seeing fewer and fewer foods using that phrase, especially as many manufacturers are now following the voluntary, industry standard that encourages “best by” to indicate the point at which quality might start to decline and “use by” to indicate safety or significant deterioration concerns.
What could happen if you eat food past its “use by” or “best by” date?
Probably nothing, but it depends.
- If you eat a shelf-stable food past its best by date, and it’s been stored and handled properly, it might taste fine, or it might taste off, but it probably won’t make you sick.
- If you eat a moist, relatively low-acid, cold food past its use-by date, it might be harboring higher levels of listeria. If the refrigerator holding it was too warm, other types of bacteria might have been able to grow. Depending on how out-of-date it is, how much bacteria may have grown and your own health status, it could make you sick. Or you could be fine. And if the food is only supporting so-called spoilage organisms (and not any human pathogens–this is theoretical, you’d have no way of knowing just by looking at the food), you won’t get a foodborne illness, per se, but your food may taste gut-wrenchingly bad. Keep in mind that food loaded with pathogens can look normal and food with no human pathogens can look obviously spoiled. (For more check out our articles about pre-cut produce, leafy greens and deli meats.)
- If you eat or a loved one eat a food calibrated for a specific nutritional need (like baby formula or a meal replacement) after the “use by” date, the critical components may have degraded and you may not get nutrients you need.
- Regardless of the date label, if you eat food that can support microbial growth that was improperly cooked, improperly cooled, and/or stored at the wrong temperature, it could make you sick. And, again regardless of the date, if the grower/manufacturer/store/food preparer didn’t follow good food safety protocols, or if you’re simply unlucky and ate food that managed to get contaminated even while everyone took all the proper food safety steps, then you could get sick. And just to cover our bases, you could also do a terrible job handling your food and not get sick simply because you were lucky and no disease-causing organisms were present.
Ultimately, eating food past its printed date isn’t a leading cause of foodborne illness. Improper cooking, storage, and handling, along with contamination, and are top reasons why people get sick from their food. So, practice good hygiene and safe cooking practices, get your food from sources you trust, and keep your fridge set to 40 degrees or less. When it comes to evaluating food past its date, use your senses, and exercise more caution around cold, moist, low-acid ready-to-eat foods.
SOURCES:
- Kathy Glass, associate director of the Food Research Institute at the University of Wisconsin.
- Nicole Martin, associate director of the Milk Quality Improvement Program and Assistant Research Professor in Dairy Foods Microbiology at Cornell University.
- Trevor Craig, corporate director of technical training and consulting at Microbac.
- Douglas L. Marshall. Chief Scientific Officer. Eurofins Microbiology Laboratories. Also: Technical Director, Refrigerated Foods Association.
- Jeremy Runyan. Business Development. Alliance Analytical Laboratories, Inc.
- Faith Critzer. Associate Professor and Undergraduate Coordinator. Food Science & Technology Dept. College of Agricultural and Environmental Sciences. University of Georgia. Interview Fall 2023.
- Shelf Life of Food: An Overview. Catherine Cantley and Janna Verburg-Hamlett. University of Idaho Extension. Published April 2021.
- Considerations for Establishing Safety-Based Consume-By Date Labels for Refrigerated Ready-to-Eat Foods. ADOPTED 27 AUGUST 2004, WASHINGTON, D.C. NATIONAL ADVISORY COMMITTEE ON MICROBIOLOGICAL CRITERIA FOR FOODS. Journal of Food Protection. Volume 68, Issue 8, 1 August 2005, Pages 1761-1775.
- ReFED Date Label Standardization Tool.
- Labeling Guidance: Best practice on food date labelling and storage advice. WRAP, Food Standards Agency (UK), Department for Environment, Food & Rural Affairs (UK).
- Industry Guidance on Setting Product Shelf-Life. Food and Drink Federation. 2017.
- Date labeling on pre-packaged foods. Government of Canada.
- Food Code Section 3-501.17 Ready-to-Eat, Time/Temperature Control for Safety Food, Date Marking. Food and Drug Administration.
- How to Determine the Shelf Life of Food: Guidance Document. Ministry for Primary Industries. New Zealand. 9 June 2016.
- CODEX GENERAL STANDARD FOR THE LABELLING OF PREPACKAGED FOODS. CODEX STAN 1-1985 (Rev. 1-1991)[1]. Food and Agriculture Organization of the United Nations.
- Guidance on date marking and related food information: part 1 (date marking). EFSA Panel on Biological Hazards (BIOHAZ), Konstantinos Koutsoumanis, Ana Allende, Avelino Alvarez‐Ordóñez, Declan Bolton, Sara Bover‐Cid, Marianne Chemaly, Robert Davies, Alessandra De Cesare, Lieve Herman, Maarten Nauta, Luisa Peixe, Giuseppe Ru, Marion Simmons, Panagiotis Skandamis, Elisabetta Suffredini, Liesbeth Jacxsens, Taran Skjerdal, Maria Teresa Da Silva Felicio, Michaela Hempen, Winy Messens, and Roland Lindqvist. EFSA Journal. European Food Safety Authority. December 2020.
- Guidance on date marking and related food information:part 2 (food information). EFSA Panel on Biological Hazards (BIOHAZ),Konstantinos Koutsoumanis, Ana Allende, Avelino Alvarez-Ordo~nez, Declan Bolton,Sara Bover-Cid, Marianne Chemaly, Robert Davies, Alessandra De Cesare, Lieve Herman,Friederike Hilbert, Maarten Nauta, Luisa Peixe, Giuseppe Ru, Marion Simmons,Panagiotis Skandamis, Elisabetta Suffredini, Liesbeth Jacxsens, Taran Skjerdal,Maria Teresa Da Silva Felıcio, Michaela Hempen, Winy Messens and Roland Lindqvist. EFSA Journal. European Food Safety Authority. Adopted March 10, 2021.
- The Dating Game: How Confusing Food Date Labels Lead to Food Waste in America. Natural Resources Defense Council. Food Law and Policy Clinic at Harvard University. September 2013.
- Food Product Dating. Food Safety and Inspection Service. U.S. Department of Agriculture.
- Confused by Date Labels on Packaged Foods? Here’s how to know if your food is still good to eat while also reducing waste in your home. U.S. Food and Drug Administration. May 23, 2019.
- Product Code Dating. FMI, The Food Industry Association.