Sometimes it can be hard to determine whether your food can still be eaten or should be thrown away.  Should you guide yourself by how it smells? How it looks? When it expires? It all depends on how the food is stored, how long it was left out in room temperature, and if it exhibits clear signs of spoilage.

Here are some guidelines to go by the next time you are doubting something in your refrigerator or pantry.

Canned Foods

Canned foods are known for their very long shelf life, but sometimes even these food products can go bad. According to the National Center of Food Preservation, the best way to know if a canned food has gone bad is to check the lid. “Do not taste food from a jar with an unsealed lid or food that shows signs of spoilage. You can more easily detect some types of spoilage in jars stored without screw bands. Growth of spoilage bacteria and yeast produces gas which pressurizes the food, swells lids, and breaks jar seals. As each stored jar is selected for use, examine its lid for tightness and vacuum. Lids with concave centers have good seals.”

When you open a can, check for the smell as well as for a cotton-like mold residue on the top surface. If you see this, you may want to dump it.

Leftovers

If the meal you’re about to eat is spotty, has a weird smell or slimy texture, it doesn’t necessarily mean it will make you sick. In fact, bacteria that makes food slimy can actually protect it. Michael Doyle, director of the Center for Food Safety at the University of Georgia in Griffin, notes, “There’s a big difference between spoilage and what’s going to make you sick. Often spoilage bacteria will outgrow the harmful bacteria and protect [the food].” Frighteningly enough, the pathogens that will actually make you sick do not have a strange smell or texture–with the exception of milk. Never drink milk that looks or smells off.

Another important factor to determining whether you should eat your leftovers is how they were stored. When was the last time you checked the temperature in your refrigerator? Many people don’t even know how cold their refrigerator should be.  According to an article by ABCNews.go.com, keeping your refrigerator at 40 degrees Fahrenheit “can slow or stop bacterial growth of either the pathogens or the spoilage variety. Forty degrees Fahrenheit buys people three days for safety with raw chicken and ground beef, three days with cuts of beef and lamb and four days for leftovers.”

What if you forgot to store the meal an hour after you finished eating? Are you still able to eat it if you put it in the refrigerator right away? Most food experts will say yes. Though not ideal, you can leave a meal at room temperature for up to two hours without spoiling it. During summer, however, food should be refrigerated within the hour, especially if outside temperatures are higher than 90 degrees Fahrenheit.

Expiration Dates

You go to the fridge and notice all the meat you bought has the same expiration date, does this mean you’re supposed to eat it all before you have to throw it away? Not necessarily. So what does it all mean?

According to Georgia Giannopoulos, RD, CDN, CNSC, a dietitian at the Weill Cornell Medical Center, when you see a date that says, “use by,” “sell by” or “best before,” “These terms are more about the food’s quality than safety.” For example, if the food says “sell by,” a certain date, that tells you how long a store can actually have the product on the shelves before having to get rid of it. “Best if used by,” tells you the date by when the food should be eaten if you want it to have the best flavor or quality. If you consume a food after the “best if used by” date, it doesn’t mean that it will be bad for you.

Meanwhile, food that is not stored correctly is even more dangerous than expired food because it could go bad even before the expiration date on the label. Image you go for the sour cream and notice there’s mold in it, even though you still have a few dates before it officially expired. If you eat it, it WILL make you sick, regardless of what it says on the label. That is why it is very important to always follow the correct storage practices.

Just Be Careful

As long as you take care to store food according to instructions, and make sure the temperature in your refrigerator is below 40 degrees Fahrenheit, you can help prevent your food from spoiling. Nevertheless, it is still important to look for clear signs of spoilage before eating something. When in doubt, throw it out. This will save you a trip to the doctor from food-related illnesses.