While some “expiration” dates are merely quality suggestions, for the following 13 foods, the date is a strict safety boundary. Eating them after their expiration can risk serious foodborne illness.
Here’s the list, focusing on why the risk is so high.
1. Infant Formula
This is the only federally regulated expiration date in the U.S., and it’s non-negotiable. After the date, the nutrients in the formula begin to degrade, which can lead to malnutrition. More critically, the packaging can develop microscopic holes, allowing bacteria like Cronobacter sakazakii to contaminate the powder, which can be fatal for infants. Never use it past the date.
2. Deli Meats (Pre-Sliced)
Once the factory seal is opened, you have 3-5 days, regardless of the sell-by date. But even an unopened package past its date is a huge risk for Listeria monocytogenes. This bacteria thrives in cold temperatures and can cause severe, invasive illness, especially in pregnant women, the elderly, and the immunocompromised. A sour smell or slimy film confirms it, but Listeria has no odor, so never risk it past the date.
3. Raw Ground Meats & Poultry
A steak can age; ground meat cannot. The grinding process takes any surface bacteria (like E. coli or Salmonella) and mixes it throughout the product. This massively increases the bacterial load and the surface area for it to grow. Cook or freeze by the “use-by” date. A gray color or sour smell means it’s already spoiling.
4. Fresh Berries
Berries are a hotbed for Cyclospora, a microscopic parasite that causes weeks of explosive diarrhea. They’re also highly porous. Once past their prime and turning soft or fuzzy, the mold and bacteria have a vascular highway deep into the fruit. The mold you see is just the tip of the iceberg; invisible toxins can permeate the water-rich berry. One moldy berry means the whole clamshell is compromised.
5. Soft Cheeses (Brie, Camembert, Ricotta, Queso Fresco)
Unlike hard cheese, where you can cut an inch around mold, soft cheeses have high moisture content, making them perfect for Listeria and E. coli to spread rapidly. The mold threads (hyphae) can penetrate the entire product invisibly. If expired or showing any mold, the entire cheese must be discarded.
6. Bagged Pre-Washed Greens & Salad Mixes
The “sell-by” date is a ticking clock for bacterial proliferation. The leaves are cut, releasing nutrients that feed bacteria in the humid, sealed bag. If the bag is puffy, that’s gas from bacterial growth. E. coli and Salmonella can multiply to dangerous levels, and since it’s eaten raw, there’s no “kill step” like cooking. Toss it the day it expires.
7. Shell Eggs (Float Test is a Myth for Safety)
You may know the “float test” for freshness, but a sinking egg can still be riddled with Salmonella Enteritidis if it’s old. As eggs age, the protective bloom weakens and the shell becomes more porous, inviting bacteria. Always cook to 160°F, but never use them weeks past the date on the carton.
8. Raw Shellfish (Oysters, Clams, Mussels)
Live shellfish must be alive when cooked. An expired or dead shellfish decomposes rapidly, producing toxins that high heat cannot always destroy. Vibrio bacteria, natural in warm waters, multiplies exponentially in a dead shell. If a shell is open and doesn’t close when tapped, it’s dead and must be thrown out. The tag on the bag has a harvest date, and it’s law that it be kept for 90 days in case of a contamination trace.
9. Fresh Sprouts (Alfalfa, Bean, Broccoli)
Sprouts are notorious for carrying Salmonella, Listeria, and E. coli because they are grown in warm, humid conditions—identical to pathogen incubators. They are almost always eaten raw. If they’re even a day past the date and have turned slimy or smell musty, the risk is extreme. For immunocompromised people, they’re often recommended to be avoided entirely, fresh or not.
10. Unpasteurized (Raw) Milk & Juice
Pasteurization kills pathogens. Without it, bacteria naturally present in the animal or fruit multiply unchecked. After the expiration date, the bacterial load can reach infectious-dose levels for Campylobacter, Brucella, and E. coli O157:H7, which can cause hemolytic uremic syndrome (kidney failure). The “freshness” date is a strict safety boundary here.
11. Cold-Pressed Fresh Juices
Unlike pasteurized, shelf-stable juice, cold-pressed juice sold in the refrigerated section has no preservatives. The high-pressure processing (HPP) reduces but doesn’t eliminate all microbes. Once past the date, any surviving spores or bacteria can activate. If the juice tastes tangy or fizzy when it shouldn’t, it’s fermenting and full of unwanted bacteria. Discard immediately.
12. Leftovers & Prepared Sides (Deli Case)
That container of potato salad or cooked chicken from the deli counter has a “packed on” or “sell-by” date, but the rule is ironclad: 3-4 days after opening/cooking, it must go. Bacillus cereus and Clostridium perfringens thrive on cooked, cooling starches and meats. They form heat-resistant spores and toxins that can’t be cooked away.
13. Molds You Can’t See (Bread & Soft Fruits)
You see one small mold spot on bread, a peach, or a cucumber. The fluffy part is the reproductive structure. The “roots” (hyphae) are microscopic threads that have already penetrated deep into the food, and in soft foods, they can spread in 24 hours. Some molds produce mycotoxins, which are heat-stable metabolic poisons. If it’s soft or porous, one spot means the whole thing is contaminated.
The Golden Rule: “When in doubt, throw it out.” Your senses (smell, sight) can’t detect many of the deadliest pathogens. The date is your best defense.