Leftovers are a normal part of cooking, but that’s especially true during the holidays when refrigerators are packed with half-finished casseroles, carved turkey, and your favorite starch-filled sides. And while many dishes stay safe for up to a week in the fridge, some leftovers do not have the long shelf life we tend to assume.

We asked food safety experts to share which foods spoil the fastest, and how you can tell. A few items even need to be eaten within a day or two! Here is what you need to keep an exceptionally close eye on this holiday season, and beyond. 

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Cooked Rice

Unlike most leftovers, rice dishes, whether from takeout or your stove, can turn risky fast. “Cooked rice should be eaten within one day of cooking,” says Vanessa Coffman, PhD, an environmental epidemiologist and director of the alliance at Stop Foodborne Illness. “Rice may contain Bacillus cereus—a bacteria that produces heat-resistant toxins if left at room temperature. These toxins remain even after reheating, causing food poisoning.”1 

To keep your dish as safe as possible, Coffman recommends cooling rice quickly after cooking (within an hour) and storing it in the fridge at or below 40°F for up to one day. (This recommendation is quicker than the common three to four day window.) When reheating, heat up the leftover rice so it is steaming hot, or at least 165°F.

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Gravy

Homemade gravy is a must-have on most holiday tables, but it’s also one of the quickest dishes to spoil. “Leftovers should typically be consumed within three to four days, while gravy should be eaten within just one day,” says Coffman, who points to the high moisture content in gravy that is ideal for “pathogenic bacteria and spoilage microbes.”

While Coffman recommends tossing or freezing gravy after a day, signs it’s gone bad include a darker color, a sour or off smell, or a texture that’s noticeably thicker or clumpy.

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Whipped Cream

Coffman says the same factors that make gravy spoil quickly also impact sweeter ingredients such as whipped cream. This fluffy dessert topper can get loaded with bacteria that “multiply rapidly once the foods warm up or are exposed to air.”

Ideally, whipped cream should be used within 24 hours of storing in the fridge (once opened or made). If it shows even a hint of mold, it’s safest to toss it and make a fresh batch.

Mayonnaise-Based Salads

Mayonnaise often gets blamed for making cold salads unsafe, but, when stored in the fridge, the real issue isn’t usually the mayo itself. “Store-bought mayonnaise is commercially pasteurized and made slightly acidic to inhibit bacterial growth,” says Coffman. That means the mayo itself is generally safe for longer than people assume.

But there’s a big caveat: “When store-bought mayo is combined with other ingredients (like eggs, potatoes, or chicken), those foods, not the mayo, usually spoil first.” Like many leftovers, Coffman suggests consuming salads made with mayonnaise within three days.

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Pasta Dishes

“Cooked pasta has a quick shelf life and should only be kept for three to four days in the fridge,” says Reena Angelique Clark, BSN, RN, a registered nurse and director of continuing education at United Medical Education. “Pasta spoils relatively quickly because it can contain a bacterium known as Bacillus cereus that forms spores able to survive the first cooking process.” 

Unlike rice, which provides an especially favorable environment for those spores to multiply and produce toxins, pasta generally contains less moisture and acidity. This, in effect, slows bacterial growth and extends the safe storage time by a couple of days.2 “You can determine if [pasta] has spoiled because it will begin to develop a noticeable slimy texture or a slightly sour, unpleasant odor,” says Clark.

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Seafood Broth

Homemade seafood stock or broth does not last as long as chicken or beef options. “They should be discarded after just two days in the refrigerator because they are highly perishable,” says Clark. “The fish proteins are rich sources of nitrogen, which offers a perfect nutrient-rich environment for spoilage bacteria. Specifically, amino acid breakdown is accelerated rapidly, and thus can form histamine, even when refrigerated, which is a chemical implicated in scombroid poisoning.”3 

Put simply, these seafood-based ingredients break down quickly in the fridge. Clark says you’ll know the broth is bad when it becomes cloudy, has a distinct and really strong fishy odor on top of its original smell, or when the surface has a slight iridescent sheen.

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Soft Cheeses

Some types of cheese can last a long time in the fridge, while others won't make it to your second charcuterie board of the month. “Leftover soft cheeses (Brie, ricotta, or cottage cheese, for example) should be discarded after five to seven days after opening of the original packaging,” says Clark. “Their high moisture content compared to hard cheeses make them great places for molds and bacteria to grow at a rapid rate.” 

Mold growth on the surface of cheese is a sure indicator that it has gone bad, but even if there is no mold on the cheese's surface, it can develop a bitter or very sour taste. Refrigerating these foods at the back of the refrigerator, in a spot where the temperature is always 40°F or lower, does help to slow down the deterioration a little.

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Unrefrigerated Leftovers

No matter what you cooked, leftovers that sat out too long have a very short shelf-life. “Food can only stay in the ‘danger zone’ (between 40°F and 140°F) for two hours before it is unsafe to eat,” says Coffman. “In this temperature range, bacteria that cause foodborne illness can grow rapidly. For example, pathogens like Salmonella, E. coli, and Clostridium perfringens can double in number every 20 minutes.”4

 If, for example, food that sat out during an outdoor picnic on a hot day, Coffman notes that the "safe" time at room temperature is reduced to just one hour. To make all your leftovers last longer, you need to cool the food as quickly as possible, meaning put it in the fridge as soon as it hits room temperature, ideally within the hour. Coffman also recommends shallow containers and reheating food to at least 165°F. “If cooked food has been left out for more than two hours, it’s safest to discard it,” she says.