What Will Eating Each Kind of Expired Food Really Do To You?

Ever wondered what would happen if you drank a pint of off-smelling milk? It’s not pretty.

What Will Eating Each Kind of Expired Food Really Do To You?

When we’re in a pinch, expiration dates oftentimes become recommendations, rather than rules. After all, what’s the worst that could happen? We asked nutritionist Carolyn Dean, who has extensive experience treating irritable bowel syndrome and other bowel diseases, to find out what happens when you eat that thing that “mostly smells okay, I think?”

Stale Bread

Stale bread isn’t just safe to eat, it’s also good for your colon, according to researchers from the Royal Melbourne Institute of Technology. One of their more recent studies, published in the journal Food Chemistry, found that stale bread contains more of what are called resistant starches than fresh bread does. These resistant starches feed the bacteria living in our intestines, which then leave behind a slew of colon-healthy chemicals like butyrate and propionate. One paper claims that these chemicals guard against obesity and regulate your gut hormones, while another says they help maintain healthy cell growth in the lining of the colon—this, in turn, could potentially prevent colon cancer.

Bread that’s visibly moldy, however, is another story. Although accidentally eating a little bit probably won’t do you any harm, the mold can cause irritation of the eyes, nose and throat if you’re allergic to it. “You may also react with asthma or shortness of breath,” Dean explains, so if you notice green fuzz growing on your bread, you’re probably better off just having a bowl of cereal instead.

Spoiled Milk

A small test-sip of spoiled milk won’t do you too much damage, but chugging an entire glass will likely cause stomach cramps, nausea, diarrhea and even fever—in other words, food poisoning. Before landing on the shelves, milk goes through a process called pasteurization, which is meant to kill off bacteria that causes spoilage (the very same bacteria that causes food poisoning). Unfortunately, some bacteria survive this process and proceed to reproduce, turning the milk into a public swimming pool filled with illness-causing germs.

Grey Meat

Although you might think seeing your meat wilt to a depressing grey hue is a reliable indicator that it’s not safe to eat, according to the USDA, color is a poor way to judge its freshness. Fresh cut meat, like beef, is naturally purple: When oxygen from the air reacts with the pigments in the meat, it forms that bright red color we all know and love. If you’ve been storing meat in the refrigerator or the freezer—away from a constant source of oxygen—for some time, it may turn grey, but grey doesn’t mean it’s bad.

What you should be paying attention to is odor and texture. If the meat is smelly and slimy, it’s likely filled with shigella, salmonella, campylobacter or E. coli—all very similar versions of food poisoning. If you’re not totally sure if your meat is okay to eat, refer to the USDA’s meat and poultry guide. Or, just throw it out.

Expired Canned Foods

According to the USDA, low-acid canned foods—vegetables, meat and fish—will last for up to five years from the day they were canned (if the date isn’t printed on the can, you can assume it’s safe to eat for at least few years after it was purchased), despite whatever the expiration date on the can says. Canned foods are also sterile, so eating an expired can of tuna, for instance, won’t necessarily make you sick—it just won’t taste as good. That said, if the can is bulging, leaking, or hisses when opened, it may be contaminated with an extremely rare toxin that causes botulism, a potentially fatal foodborne illness. But you already know not to eat food that’s literally seeping from the can…don’t you?

Frozen Foods

You may be surprised to learn that foods from the freezer section of the supermarket are safe to eat indefinitely—they only have expiration dates because their flavor and texture will diminish over time. To find out how long all other foods can be stored in the freezer, check out this food safety guide. It’s important to note, however, that freezing does not kill E. coli and other foodborne bacteria, so bad meat is still bad meat, whether it’s frozen or not.