There’s a good chance you bought that extra-large bird for Thanksgiving dinner so that family and friends can enjoy leftovers. But food scientists warn that it’s critical to keep foods correctly stored to ensure freshness and safety. 

According to Scientific American, the U.S. Department of Agriculture’s (USDA) Food Safety Inspection Service recommends throwing out refrigerated leftovers after three to four days. If food is properly stored in the freezer, it can still be consumed safely for three to four months.

While smell can be a good indicator that food has gone bad, it’s not always an accurate way to measure freshness. Disease-causing bacteria typically don’t change food’s smell, flavor, or appearance. Animal products like meat and dairy tend to spoil faster because pathogens can grow on leftovers and make people sick. Bryan Quoc Le, a food scientist and author of 150 Food Science Questions Answered, recommends throwing away dairy and meat products by the end of the third day after cooking them.

Foods high in sugar or salt can slow down microbial growth, while water or moisture in foods can help bacteria, yeast and other microorganisms grow faster. Acidity is another factor. Canned cranberry sauce has a pH of 2.4, and Le says only a few pathogens can survive in such acidic conditions. Meat and dairy, on the other hand, have a neutral pH, making them a more ideal environment for microorganisms to grow.

The USDA says that leaving food out on the table that has an internal temperature of 40 to 140 degrees Fahrenheit is typically considered “the danger zone.” Le says you should seal and store leftovers as soon as possible after cooking, because harmful bacteria can rapidly divide and contaminate the food. “Every 20 minutes the food is left out in room temperature, microorganisms are doubling in number,” he tells Scientific American.

According to experts, if turkey, stuffing, or gravy is left at room temperature for over two hours, it may no longer be safe to eat. This is the biggest mistake made at holiday gatherings, as people have a habit of leaving food on the buffet table far too long before storing it away, so that bacteria prosper.

But when stored safely in the refrigerator, turkey leftovers generally are good to eat for two to three days. The Centers for Disease Control and Prevention says that one should “refrigerate leftovers at 40 degrees Fahrenheit or colder as soon as possible and within two hours of preparation to prevent food poisoning.” Package the leftovers in smaller serving sizes before storing to discourage bacteria from growing.

If you are planning to eat the leftovers after the recommended two-to-three-day period consider freezing them ─ which keeps them safe from two to six months. Here are some other tips for storing typical Thanksgiving Day dishes:

• Mashed potatoes. When left at room temperature (40 degrees to 140 degrees Fahrenheit) for too long, mashed potatoes or any cooked potatoes can develop botulism due to the bacteria present. When baked in foil, this is even more prevalent. According to Insider, reheating doesn’t always get the potato hot enough to kill the bacteria, even if the dish is piping hot. If you didn’t store your spuds in the refrigerator right after eating, don’t risk food poisoning by eating them the next day.

• Mushrooms. If you served sauteed mushrooms as part of your holiday dinner, reheating and consuming mushrooms that have been left too long at the table can cause stomach distress. If you really must reheat mushrooms, the European Food Information Council recommends warming them to at least 150 degrees Fahrenheit.

• Stuffing. Because it’s prone to developing pathogenic bacteria, eating leftover stuffing can be dangerous. It may not smell or look different, but it still can make you sick.

• Turkey. Raw turkey is a hotbed of bacteria that can also contaminate other foods so store your bird safely away from other food in the refrigerator. Even when sufficiently cooked, poultry presents certain dangers says Healthline,  particularly when dealing with a turkey that’s been left out to develop bacteria for hours on Thanksgiving Day.

• Foods on buffet. Buffet dishes that have been left out for hours at room temperature are breeding grounds for dangerous microorganisms, says the Food and Drug Administration. If you are hosting a buffet-style party, never add fresh food to an already-filled serving dish and discard any perishables left out for more than two hours at room temperature in cool weather or one hour in warm weather.

Bear in mind eating leftovers straight from the fridge increases the risk of contracting foodborne illness. To reduce those risks, cook all foods to at least 150 degrees Fahrenheit, say experts. If you do get sick, despite all your precautions, throw out the foods you suspect may have made you ill immediately.