Food expiration dates are confusing — and not just because they don’t necessarily indicate when you should throw food out. “Sell by” and  “best by” refer to peak quality, not safety. And to add to the confusion, the terms aren’t federally regulated or required (except in the case of baby formula and certain baby foods). Most foods are fine after the dates on their packaging pass, though they may be slightly subpar. 

There are a handful of foods, however, where timing actually does matter. In these cases, it’s less about flavor and more about whether that meal is going to haunt you tomorrow. The common thread is bacteria: Moist, low-acid, ready-to-eat foods make especially good hosts, and the pathogens that can make you sick (like listeria and salmonella) don’t always announce themselves with a smell. Here are the foods you should toss once the expiration date has passed (or sooner if you’ve opened them).

Deli Meat and Cold Cuts 

Lunch meats are prime territory for listeria, a bacterium capable of growing at temperatures as low as 31 degrees Fahrenheit — meaning “well, it stayed cold” isn’t the protection it seems to be. And, as the FDA notes, the longer a ready-to-eat refrigerated food sits, the more opportunity listeria has to grow. 

While it’s rare for healthy people to get extremely ill from listeria infection, it can be fatal for newborns and those who are immunocompromised, and it can cause miscarriages in pregnant people. So you shouldn’t let freshly sliced deli meat linger too long in your fridge: It has only three to five safe days before you should toss it out. The prepackaged versions you get in the refrigerated aisle last a little longer if they’re unopened — usually about two weeks — but once the seal is broken, you’re back to the same short window.

Soft Cheeses 

Solid blocks of hard cheeses (cheddar, Parmesan, and pecorino, for example) are very forgiving. They last for up to four weeks in your fridge, and even if they get a little moldy, they’re not a lost cause — just cut an inch around the moldy spot and carry on. (If your hard cheese is grated or shredded and exhibits signs of mold, though, you should throw it out.)  

When it comes to soft, high-moisture cheeses like ricotta, cream cheese, goat cheese, or brie, it’s best to follow package guidelines. And definitely toss them at any sign of mold: In soft cheese, it spreads throughout and can’t be cut out. Soft cheeses are also more prone to listeria. The Academy of Nutrition and Dietetics suggests using cream cheese within two weeks of opening, and ricotta within one. Bottom line: Toss at the first sign of spoilage or by the date on the package — whichever comes first.

Raw Fish and Shellfish 

Seafood is one of the most perishable things in your kitchen. Eating improperly stored fish can cause various types of food poisoning, resulting in an upset stomach, diarrhea, or worse. For this reason, the USDA recommends cooking or freezing raw fish within 48 hours of purchase. Certain types of shellfish give you a little more leeway: Clams, mussels, and oysters need to be eaten within three days if you buy them live or in five to 10 days if they’ve been commercially shucked and jarred. Scallops should be consumed within one to three days. Any sour, fishy, or ammonia-like smell is your cue to throw seafood out immediately. And while we don’t want to scare you, here’s one additional thing to consider: There are some types of food poisoning you can get from fish that no amount of cooking can prevent. If you feel sick after eating seafood, seek medical advice.

Ground Meat 

Think about this: A steak carries bacteria mostly on its surface, which is why searing the outside does a lot of work in making it both safe and tasty. However, it’s smart to consider whether your meat has been mechanically tenderized. The process, which involves poking the meat with sharp needles to break up the muscle, can transfer bacteria into the center of the steak. Similarly, grinding meat mixes that bacteria all the way through, so ground beef, turkey, and pork spoil faster and carry more risk. The USDA says to use or freeze ground meat within two days of purchase. 

Bagged Salads and Leafy Greens 

Leafy greens can carry bacteria that may become a problem once the leaves break down and get soggy, allowing the bacteria to proliferate. So, once greens go slimy or brown, they’re done (and wilted salad, being what it is, means you probably wouldn’t want to use them anyway). This applies even to prewashed mixes. According to FoodSafety.gov, bagged produce, if unopened, “will last [three to five] days after date on bag; after opening it will last [two] days.”

Sprouts 

Bean sprouts can elevate a sandwich with crunch and freshness in a way few other veggies can, but beware: These tiny shoots are grown in exactly the warm, humid conditions bacteria love. Salmonella, listeria, and E. coli can all be found on raw sprouts. The FDA notes that if even a few harmful bacteria are present on the seed, they can multiply to high levels during sprouting.  The safe window is short — roughly five to 10 days after purchase — and if you’re pregnant or immunocompromised, the FDA advises skipping raw sprouts altogether.

Mayonnaise and Creamy Dressings 

Mayo, aioli, and many creamy dressings are egg- and dairy-based and high in moisture, which makes them hospitable to bacteria once the seal is broken and a knife is going in and out of the jar. The USDA gives open commercial mayonnaise about two months in the fridge; creamy dressings have three to four weeks in the fridge. Even if the date hasn’t yet approached, if it smells off or looks weird, throw it out. 

Prepared Deli Salads 

Potato, egg, tuna, and pasta salads combine a few risk factors at once: They’re moist, often mayo-based, and scooped with a spoon, which can introduce bacteria. That exposure adds up fast, especially if the container is taken out of a cold fridge and drifts into the danger zone that allows bacteria to thrive (between 40 degrees Fahrenheit and 140 degrees Fahrenheit). Deli salads like coleslaw, potato salad, and tuna salad are among the ready-to-eat foods that can carry listeria, which will thrive even if you put the dish back in the fridge. The USDA gives store-bought and homemade deli salads about three to five days — and unlike a wilted salad, a contaminated one won’t necessarily look or smell wrong, so play it safe and toss it when that timer is up (or sooner if it’s been allowed to linger at room temperature).

Cold-Pressed Juice 

The reason raw green juices cost what they do is also why they don’t last: They skip the pasteurization that kills bacteria, which leaves them prone to contamination and with a short life of three to five days once opened. Untreated juices are required to carry a warning label, and the FDA advises that children, older adults, pregnant people, and anyone immunocompromised should avoid them.

The Takeaway 

The catch with all of these is that the sniff test gets you only so far. A funky smell is a good reason to toss something, but it’s important to also remember that the absence of funk isn’t a good reason to eat it — listeria and salmonella can be present with no smell at all. 

For most of your pantry (especially dry goods), the dates on the packaging are a loose suggestion and your nose is a fine backup. For this short list, however, the date and the open-container clock are both worth taking at their word — and when you’re genuinely unsure, the few dollars you’d lose chucking the item are rarely worth the discomfort you’d suffer if it is indeed spoiled.

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It happens to all of us: You’re chopping veggies for a salad or shoveling popcorn into your mouth while watching a movie, and a morsel of food ends up on the floor. Thoughts pass fleetingly through your mind: If you pick it up quickly, is it still OK to eat? Is the five-second rule a real thing? The answers to these questions may be more complicated than they seem.

Background on Bacteria

No matter how well you wash your hands or scrub your sink, you spread bacteria among any surfaces you touch. A 2012 study found that human skin was the main source of bacterial transfer across kitchen surfaces, and that infrequently cleaned areas like exhaust fans, refrigerator door seals, and floors had the highest diversity of bacteria. 

At the same time, anything that touches a surface in your kitchen — including food — picks up bacteria. A Dorito doesn’t have to fall on the floor to acquire a few microbes; it could simply come into contact with the kitchen counter, which actually harbors more coliform bacteria per square inch than the floor, according to a 1998 study. Cutting boards, dish towels, and sponges can also bear bacteria and spread them among the surfaces they touch.

The important thing to remember is that most bacteria found in kitchens and food-prep areas are not harmful to your health. However, pathogens such as salmonella and E. coli, which are often brought into kitchens via contaminated meat or produce, can linger on improperly cleaned surfaces. If you drop a piece of food and it falls directly on disease-causing bacteria on the floor, you could, theoretically, get sick from eating that food — but chances of that happening are low, Paul Dawson, a food scientist at Clemson University, told Prevention.

Five-Second Rule Fiction?

The apocryphal five-second rule suggests that food that’s dropped on the floor is safe to eat if it’s retrieved within five seconds, ostensibly because it doesn’t have time to acquire pathogens. Dawson led a frequently cited 2007 study that assessed whether the rule was scientifically sound by dropping sliced bread and bologna on tile, wood, and carpeted floors contaminated with salmonella and measuring the bacterial loads the foods picked up after various amounts of time. 

Though the carpet-to-bologna pathway transferred less than 1% of bacteria, “over 99% of bacterial cells were transferred from the tile to the bologna” after five seconds. Overall, 48% to 70% of bacteria moved from wood or tile floors to the bread and bologna within seconds, disproving the basic idea that brevity of time prevents bacterial migration from floor to food.

Later studies have shown that the moisture content of the food, the floor material, and duration affect bacterial transfer. In general terms, the stickier or wetter the food is, and the longer it spends on the floor, the more bacteria it’s going to acquire, though carpet tends to transfer fewer bacteria than harder surfaces. 

The Bottom Line 

Food that’s been dropped on the floor is unlikely to make you sick. But if you decide to eat it, give it a thorough rinse. Anything you can’t wash should be thrown out.

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Fresh fruits and vegetables seem so innocent when stacked in dewy rows at the grocery store. But produce and other common foods can be vectors for parasites if proper handling guidelines aren’t followed, and these bugs can make you sick if you’re not careful. Here’s what could be lurking in your lettuce — and what you can do to stay safe.

Giardia

In 1681, when the pioneering microbiologist Antonie van Leeuwenhoek peered through a microscope at a sample of his own feces, giardia stared back at him. This protozoan parasite’s life cycle includes a stage as an infectious cyst that can contaminate food, water, soil, and other substances. When ingested, the cysts colonize the host’s small intestine and change into their active form, allowing them to absorb nutrients and multiply. Eventually the parasites make their way to the host’s colon, turn back into infectious cysts, and exit the host’s body through defecation.

Giardia is the most common intestinal parasite in humans, and it can be found worldwide. Symptoms of infection include frequent diarrhea, gas, stomach cramps, and nausea, and untreated cases can lead to irritable bowel syndrome and other complications. 

To avoid this unpleasantness, wash your hands after touching potentially infected substances and before preparing food; wash fresh produce thoroughly with clean water; cook fruits and vegetables to kill any parasites; never drink untreated water from lakes, rivers, or streams; and clean and disinfect any potentially contaminated surfaces.

Cryptosporidium

Like giardia, cryptosporidium is transmitted through the “fecal-oral route”: Hosts (including humans) ingest the microscopic parasites via contaminated food or water, the parasites multiply in the host’s gastrointestinal tract, and then the parasites exit the host in feces. Symptoms of crypto infection range from diarrhea and stomach discomfort to low fever and loss of appetite. Immunocompromised people can experience more severe and long-lasting effects. 

People contract cryptosporidium by accidentally swallowing contaminated water while swimming (including at the pool — chlorine can’t kill it), eating contaminated produce or unpasteurized dairy products, or coming into contact with infectious feces (such as when changing an infant’s diaper). The best ways to prevent a nasty bout of crypto are washing produce before consuming it, avoiding unpasteurized foods and untreated water, and frequently washing your and your grandkids’ hands. 

Cyclospora

Humans are the only known hosts for cyclospora, which made headlines in July 2026 when an outbreak of the intestinal infection it causes hit several U.S. states. Preliminary results from the Food and Drug Administration’s investigation linked the cases to contaminated iceberg lettuce. 

Cyclospora is another microscopic parasite transmitted via the fecal-oral route, most often through produce or water contaminated with human poop. Infections can be asymptomatic, or they may cause gastrointestinal upset, diarrhea (“possibly explosive”), weight loss, bloating, and flu-like symptoms. Health agencies recommend thoroughly washing and peeling raw fruits and vegetables and then cooking them to 158 degrees Fahrenheit to kill potential cyclospora; washing alone, especially with a bit of dish soap, may reduce the number of parasites clinging to produce but may not eliminate them completely. Experts also suggest drinking only purified or bottled water when traveling outside the U.S. where sanitation practices are less rigorous and cyclospora is endemic.

Toxoplasma gondii

For a single-celled parasite, Toxoplasma gondii can lead to a lot of problems. T. gondii causes toxoplasmosis, an illness with a constellation of symptoms ranging from mild muscle aches in healthy people to damage to the eyes, brain, and other organs in immunocompromised people.  Pregnant people are particularly at risk because the parasite can cause miscarriage or congenital toxoplasmosis in babies, leading to further health issues down the line.

Cats are T. gondii’s primary hosts. The parasite colonizes feline intestines, and people usually contract toxoplasmosis by ingesting undercooked meat (including shellfish), as well as produce, soil, or water contaminated by cat feces. Dealing with your cat’s litter box is another common mode of transmission. To avoid getting sick, wash hands and all food prep surfaces and utensils before and after use. Wash and peel fruits and vegetables before eating them and don’t consume raw shellfish or raw dairy. Don’t forget to wear gloves when gardening and emptying your cat’s litter box.

Trichinella

Trichinella — a genus of roundworms — is conveyed in raw meat. People usually contract trichinellosis by eating raw or undercooked wild game, including deer, moose, seal, or bear, or pork purchased “on the hoof” (in other words, a whole animal bought directly from a farmer, then butchered for personal consumption), that contains trichinella larvae. After being consumed, the larvae grow into adult worms in the host’s small intestine. Females then release new larvae that migrate to the host’s striated muscle tissue. Symptoms at this stage include swelling and inflammation around the eyes, fever, joint aches, and muscle pain.

The easiest way to avoid trichinella is to cook wild game to a safe temperature using a meat thermometer. Cuts of pork less than 6 inches thick can be frozen at 5 degrees Fahrenheit for three weeks to kill T. spiralis, the species of roundworm found in domestic pigs (though freezing at any temperature doesn’t work on game, which usually carries T. nativa, a hardier species). Be sure to wash and disinfect any surfaces that come into contact with raw meat, including your hands.

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The federal government’s consumer-facing food safety pages — including FoodSafety.gov and websites for the FDA, the CDC, and the USDA’s Food Safety and Inspection Service — contain pretty much all the information you need as a home cook to avoid food poisoning. Most of it comes down to basic concepts like the “four simple steps” shown on the homepage at FoodSafety.gov: clean, separate, cook, and chill. But occasionally, a specific piece of information you’re looking for isn’t easy to track down, or even to spot once you’ve found the correct page. 

For example, most of these pages talk about reheating leftovers to 165 degrees Fahrenheit. But what about leftovers you plan to eat cold? Are they safe to eat? That answer takes some digging. Let’s break it down. 

Why Leftovers Are Usually Reheated to 165 Degrees Fahrenheit

The typical advice for leftovers is to reheat them to 165 degrees Fahrenheit. That’s because they often include foods with a high level of risk, such as meats, dairy, eggs, seafood, and poultry. Add in starches and any liquid sauces, and you have a lot of prime real estate for bacteria to set up shop. 

Cooking food the first time usually kills any bacteria it might have contained, especially if you reached the USDA-recommended food-safe temperatures of 145 degrees Fahrenheit for meats, 160 degrees Fahrenheit for ground meats, and 165 degrees Fahrenheit for poultry. But bacteria can find their way back to your food after it’s cooked — from your hands, from dirty utensils, or from being present in droplet form in the air. 

Reheating leftovers to the recommended 165 degrees Fahrenheit is enough to kill illness-causing pathogens like salmonella that might have recolonized your food. But that doesn’t mean all leftovers are automatically safe if you heat them to that temperature. A few kinds of dangerous bacteria produce toxins that linger even if the bacteria themselves are killed, and those can still make you seriously ill. That’s why government sources recommend discarding any food that’s been left out at room temperature for more than two hours, or that’s been in your fridge for more than three or four days. 

Leftovers Are Usually Safe To Eat Cold (If You Handle Them Correctly)

But what about leftovers that you plan to eat cold? A quick search of the usual food safety sites doesn’t turn up any obvious guidance on the subject, but the information is there if you do a bit of digging. 

If you look in the USDA’s Kitchen Companion, for example, you won’t see anything about eating leftovers cold. But in the section on takeout/delivery food, you will find a discussion of keeping cold-prepared foods (essentially leftovers or made-aheads) cold for later consumption. 

A stand-alone USDA handout on the same subject goes further. After describing the correct procedure for first refrigerating or freezing leftovers (hot or cold), and then thawing them if necessary, it explicitly states that “the food may be eaten cold or reheated.” Similarly, a handout specifically about food safety for turkey dinners says that the turkey can be eaten “either cold or reheated” for three to four days. 

So the short answer is yes — usually, leftovers are safe to eat cold, provided you follow food safety guidelines. Then the question is: Are you familiar with those guidelines, and if so, have you actually followed them? 

A Quick Primer on Food Safety for Leftovers

If you don’t have time to sort through publications and websites about food safety, here’s a quick cheat sheet of what you need to know for leftovers specifically: 

• Chill your leftovers ASAP. Don’t wait for them to come to room temperature first (your fridge can handle it). Leftovers should never sit at room temperature for more than two hours, or more than one hour if the temperature is above 90 degrees Fahrenheit. 
• Portion big-batch leftovers, like a pot of chili or a full-sized roast or turkey, into small, flat containers for refrigerating or freezing. Several small, shallow portions cool off a lot faster than one big container, which means less time spent in the danger zone (above 40 degrees Fahrenheit, but below 140 degrees) where bacteria can thrive.
• Eat your leftovers within three or four days if they’re refrigerated, or freeze them if you know you won’t eat them within that time frame. 
• If you freeze your leftovers, thaw them safely. The best method is overnight (or longer) in the fridge, but thawing in cold water is OK if you eat them that day. The microwave should be used only if you plan to eat them right away, because it heats unevenly and some parts of the food may reach an unsafe temperature. And never thaw leftovers by leaving them on the counter — that’s just asking for trouble.
• Leftovers that have been thawed in the fridge are also good for three to four days if they were frozen the same day you cooked them. Your maximum is a total of four fridge days, so if you froze them two days after cooking, and thawed them for a day in the fridge, you now have only one day left to eat them.  

At this point you may wonder: If leftovers are safe to eat cold, why the emphasis on reheating to 165 degrees Fahrenheit? It’s because once you start heating up those leftovers, you put them squarely into the food safety danger zone. So at that point you’re committed and need to keep going until the food reaches 165 degrees Fahrenheit. 

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