10 Leftover Foods That Can Become Unsafe When Reheated

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Leftovers can be a convenient way to save time and reduce food waste, especially after a busy day. Many people simply place yesterday’s meal in the microwave and assume it’s perfectly safe to eat again. While reheating food is common, it isn’t always as simple as it seems.

Certain foods can harbor bacteria if stored improperly, and reheating them may not always eliminate the risk. In some cases, reheating can also affect the food’s texture, flavor, or nutritional quality. Because of this, it’s important to know which leftovers require extra care when reheating.

Here are 10 leftover foods that can become unsafe when reheated if they are not stored or handled properly.

Seafood

Seafood can spoil quickly, which makes it one of the trickier leftovers to reheat. Fish and shellfish can develop bacteria if they aren’t refrigerated promptly after cooking.

If you do reheat seafood, make sure it was stored properly and heat it thoroughly. Many people prefer using leftover seafood cold in dishes like salads or sandwiches instead.

Spinach

Spinach contains naturally occurring nitrates that can change when it is repeatedly reheated. While the risk is generally low, reheating spinach multiple times may lead to the formation of compounds that aren’t ideal for health.

Because of this, spinach is often best eaten fresh or added cold to salads, wraps, or pasta dishes.

Potatoes

Cooked potatoes can become risky if they are left at room temperature for too long. Under certain conditions, bacteria that produce toxins can develop, and those toxins may not be destroyed by reheating.

To stay safe, refrigerate potatoes soon after cooking and avoid leaving them out for extended periods.

Related: Before You Dump Those Potato Peels, Wait Until You See What They Can Actually Do

Rice

Rice is surprisingly one of the most common foods linked to food poisoning. Cooked rice can contain bacterial spores that multiply if the rice is left sitting out for too long.

Reheating rice won’t always destroy the toxins these bacteria produce, so it’s important to refrigerate rice quickly and reheat it thoroughly.

Pizza

Pizza leftovers often contain meat, cheese, and other toppings that can spoil if they aren’t stored properly. While reheating pizza is generally safe if it has been refrigerated promptly, improperly stored slices can allow bacteria to grow.

For best results, store pizza in the refrigerator and reheat it in an oven or skillet rather than leaving it at room temperature.

Mushrooms

Mushrooms contain proteins that can break down when they are reheated multiple times. If they are not stored correctly after cooking, they may also develop bacteria that can cause digestive discomfort.

They’re usually best eaten immediately after cooking or used cold in salads and other dishes.

Pasta

Pasta itself usually reheats well, but the sauces that accompany it can be more problematic. Cream-based or dairy-heavy sauces can develop harmful bacteria if left unrefrigerated for too long.

When storing pasta leftovers, refrigerate them quickly and reheat them thoroughly before eating.

Related: 19 Frugal Depression Era Recipes That Were Cheap, Filling, and Surprisingly Tasty

Eggs

Egg-based dishes such as scrambled eggs, omelets, or boiled eggs can sometimes become unpleasant when reheated. Reheating eggs may change their texture and occasionally cause digestive discomfort for some people.

If eggs have been stored properly, they can still be reheated safely, but many people prefer using leftover eggs cold in sandwiches or salads.

Cooking Oils

Certain oils can break down when repeatedly heated at high temperatures. This is especially true for oils used in fried foods that are reheated multiple times.

Overheated oils may produce compounds that affect flavor and quality, so reheating fried foods should be done carefully.

Related: 14 Odd, But Useful Olive Oil Hacks That Actually Work

Chicken

Chicken is a common leftover, but it must be stored properly and reheated thoroughly to avoid bacteria such as Salmonella. If cooked chicken is left out too long before refrigeration, reheating may not make it safe to eat.

To reduce risk, refrigerate chicken leftovers promptly and heat them until they are steaming hot before serving.

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