However, if you have this habit, it’s time to change. Recently, I read about the tragic story of a 50-year-old man who suffered from severe dia.rrhea after eating leftovers at home. Despite being treated in the hospital, he pas.sed away.

Specifically, the man (whose name was not disclosed) from China was admitted to the hospital after being treated with an IV for severe diarrhea, occurring more than ten times a day. However, while receiving IV fluids, he suddenly fainted and was transferred to a higher-level hospital for emergency treatment. Sadly, upon arrival, his heart stopped, and after nearly 40 minutes of resuscitation, he could not be sa.ved.

Doctors explained that the man might have developed acute enteritis after eating food that had been left in the fridge for too long. Enteritis caused severe diarrhea, leading to an electrolyte imbalance in his bo.dy, which eventually resulted in acidosis and hyperkalemia, becoming life-threatening and ultimately fatal.

How Da.ngerous Is Leftover Food Stored Overnight, Can It Even Cause Can.cer?

The foods mentioned here are not only those that have been stored overnight but those that have been stored for over 8-10 hours. Therefore, in daily life, many foods, even if not left overnight, can still be considered as leftovers.

To confirm the impact of leftover food on human health, the Ningbo Food Testing and Inspection Institute conducted an experiment:

Researchers bought common ingredients from the market, including meat, fish, and vegetables, and cooked 30 dishes using methods common in most households. Then, they divided the dishes into categories: meat dishes, half meat and half vegetables, vegetarian dishes, and cold dishes, and stored them at 4°C and 25°C, respectively. The results showed:

• For vegetables stored at 4°C for no more than 6 hours, the nitrite content did not change much, and microbial growth was minimal.

• For vegetables stored at 25°C for more than 6 hours, while the nitrite content did not change significantly, microbial growth increased substantially.

In general, as long as food is stored at low temperatures + in clean packaging or wrapped with food film, and leftovers are stored at 4°C for no more than 24 hours, the levels of nitrites, microorganisms, and the risk of exceeding safety standards are minimal, making it safe to eat.

Therefore, leftover food can only potentially cause cancer if consumed improperly and for an extended period. While vegetables stored overnight under specific environmental conditions and times may not be harmful to human health, it doesn't mean they are completely harmless.

In theory, even though you can eat overnight vegetables, there is still the risk of nutrient loss and bacterial growth, so it’s best to avoid eating too much of it. Of course, fresh food is always a better choice.

The 4 Foods You Should Never Eat After Being Stored Overnight

1.  Mushrooms and Wood Ear Fungus

If food made with mushrooms or wood ear fungus is stored overnight, the complex protein compounds in these foods can harm the digestive system when reheated. Additionally, mushrooms and wood ear fungus, whether cultivated or wild, contain high levels of nitrates. When stored for too long, these nitrates can generate to.xins, causing stomach discomfort. Therefore, the ideal time to consume mushrooms and wood ear fungus is on the same day they are cooked.

2.  Leafy Greens

Leafy greens, especially those high in nitrates, can have significantly increased nitrite levels when stored at room temperature for too long. The nutrients in these vegetables, particularly in the stems and leaves, are also significantly depleted when left too long, which is why they should be eaten fresh.

3.  Soy Products

Soy-based products like tofu and soy milk are rich in protein and other nutrients, making them an ideal breeding ground for microorganisms. Furthermore, if tofu and soy milk are left for long periods, they can be contaminated with Clostridium botulinum, a bacterium that can cause nerve paralysis and even de.ath.

4.  Soft-Boiled Eggs

Soft-boiled eggs, where the yolk is not fully cooked, are not completely sterilized. Eggs contain many nutrients, so if left too long, harmful bacteria can proliferate.

5.  Seafood

Some bacteria in seafood are not fully eliminated at high temperatures, and after refrigeration, these bacteria can multiply again. This can produce harmful protein breakdown products that could da.mage liver and kidney functions, making seafood unsuitable for consumption after being stored overnight.

How to Safely Store Leftovers

1.  Store at Low Temperatures: Leftovers should be stored at low temperatures to prevent rapid bacterial growth.

2.  Separate Vegetables and Meat: Store vegetables and meat separately, and seal them tightly with plastic wrap or in airtight containers.

3.  Watch the Storage Time: Pay attention to the storage time of cooked food.

4.  No More Than One Night: Do not store food at low temperatures for more than one day, and limit reheating leftovers to only once.

The Truth About Leftovers: Food Safety Mistakes That Could Put Your Health at Risk

Leftovers are part of everyday life. A little rice from lunch, some vegetables from dinner, a container of soup, or a few pieces of cooked fish may seem too valuable to throw away.

Refrigeration makes it possible to preserve food and reduce waste. However, putting something in the refrigerator does not automatically make it safe.

Food safety depends on several factors, including how the food was prepared, how long it remained at room temperature, how quickly it was refrigerated, the temperature of the refrigerator, and how it is reheated.

This is why two dishes that have both been stored overnight may have very different safety profiles.

One may be perfectly safe to eat after proper refrigeration and reheating. Another may already contain dangerous bacteria or toxins because it was left out for too long.

The key is understanding that food poisoning is not simply a matter of whether food is fresh or leftover. It is largely about how food is handled.

1. The Biggest Danger Is Often the Time Food Spends at Room Temperature

Many people believe that food becomes unsafe only after it develops an unpleasant smell, changes color, or starts tasting strange.

Unfortunately, this is not always true.

Some harmful microorganisms can multiply in food without producing obvious changes in appearance, smell, or taste.

A dish may look completely normal and still contain enough harmful bacteria to cause illness.

When cooked food is left at room temperature, microorganisms that survive cooking or enter the food afterward may begin multiplying.