What happens if you eat bad leftovers?

In this short article, we will provide an answer to the question “what happens if you eat bad leftovers?”, proper ways of storing leftovers in, and the most commonly found leftovers of eatables in our household which may lead to food poisoning.

What happens if you eat bad leftovers?

If you eat bad leftovers, you might experience different symptoms of food poisoning like nausea, vomiting, diarrhea, stomach cramps, and fever (1-3).

It is therefore very important that you seek medical attention immediately!

When you leave your leftovers at room temperature for a long time, different types of harmful bacteria like Salmonella, E. coli, and Listeria can colonize your food and produce toxins that lead to food poisoning (4-7).

You should not eat bad leftovers as they can also lead to more serious complications like kidney failure, dehydration and even death when contaminated with potent toxins (1-3). 

You should be more careful especially if you belong to one of the food poisoning risk groups that includes pregnant women, children, the elderly, or you have a disease that makes your immune system weak (1-3).

Remember that it is very important to handle and store your leftovers properly and throw bad leftovers away to reduce the risk of foodborne illness.

What are the symptoms of food poisoning from bad leftovers and how to react if you have eaten them?

The symptoms that you can experience after eating bad leftovers will vary depending on the amount of food that you consumed and the type of bacteria (1-3). You will probably experience:

  • Nausea and vomiting
  • Diarrhea or bloody stools
  • Abdominal cramps and pain
  • Headache
  • Fever
  • Chills
  • Weakness
  • Loss of appetite

If you have eaten bad leftovers and you are experincing one of the above-mentioned symptoms, you should:

  • Stay hydrated to replace the fluids lost through diarrhea and vomiting.
  • Seek medical attention immediately if you are experiencing severe symptoms, such as high fever, dehydration, or bloody stools. Also be more careful if you belong to one of the high-risk groups previously mentioned. It is possible that you need treatment with antibiotics to control your infection (1).
  • Avoid contact with others to avoid spreading the bacteria that caused the contamination until you have fully recovered.
  • Finally, it is very important that you throw  your leftovers away once you suspect that your symptoms are due to food poisoning. You are responsible for preventing others from consuming your spoiled food and getting ill!

Remember that you can prevent food poisoning if you handle and store your leftovers properly, including refrigerating them promptly and reheating them to an internal temperature of at least 165°F (74°C) to kill any bacteria that may be present (8).


You should always avoid consuming food leftovers that have been left at room temperature for more than two hours!

How can you tell if leftovers are safe to eat?

The following signs will help you to determine if your leftovers are safer or not to eat:

  • Check the expiration date: You should throw them out if they passed their expiration date.
  • Check the smell: If you identify a sour or off smell in your leftover, this is an indication that they may have gone bad. Throw them out immediately!
  • Check the appearance: If your leftovers have changed color, become slimy, or have mold growing on them, you should also discard them.
  • Taste: If you suspect that your leftovers may have gone bad do not taste them- it can be dangerous! If your leftovers taste bad, they should be thrown out immediately.

Remember that it is better to be on the safe side of caution and throw your leftovers out if you suspect that they have gone bad to avoid the risk of food poisoning.

How to safely keep your food leftovers to avoid food poisoning?

Remember that leftovers are delicious and convenient, and you want to make sure that they are kept as fresh and safe as possible. Here are a few suggestions:

  • For starters, don’t leave leftovers out for more than two hours at a time. 
  • Following that, food may reach a potentially dangerous temperature range (40 to 140°Ft), promoting the development of harmful microorganisms (8-9).
  • It is also advised that if you reside in a hot environment, you should refrigerate leftovers within one hour after cooking them (10). 
  • If you are unable to place the leftovers in the refrigerator before the time limit expires, it is recommended to throw them away.

The main reason why restaurant leftovers may be more dangerous than home-cooked meals is that they are not subjected to the 2-hour guideline. 

If you order takeout or have it delivered, you may not be able to get it inside the refrigerator in time to save the day. 

What are the most frequently found leftovers that can make you sick?


Salmonella is nearly usually detected in eggs, which is a bad thing (5). In certain instances, moderate heat applied for a short time may not be sufficient to kill germs (11). 

Eggs taste best when they are fresh and scrambled fast, so don’t keep them in the fridge or freezer for later use.


When cooked at a higher temperature for longer lengths of time than eggs, potatoes may still be hazardous if allowed to cool and be stored at room temperature for extended periods. 

As a consequence, the bacteria Clostridium botulinum, which causes botulism, may be able to flourish (12). 

Baked potatoes that have been covered in aluminum foil are particularly susceptible because they offer bacteria with an ideal low-oxygen environment (13). 


Bacillus cereus, a bacterium that can live at room temperature, first came to public attention in the 1970s when a series of food poisoning cases related to leftover rice increased awareness of the bacteria (14). 


In this short article, we provided an answer to the question “what happens if you eat bad leftovers?”, proper ways of storing leftovers in, and the most commonly found leftovers of eatables in our household which may lead to food poisoning.


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