Eating leftover rice can make you sick with food poisoning if it's not stored properly, experts have warned.

This is because cooking rice doesn't always kill all the pathogens living on it.
This risk of getting food poisoning from rice is raised when it's left at room temperature.

Dr Benjamin Chapman, a Food Safety Specialist from North Carolina State University, told Lifehacker: "One pathogen, Bacillus cereus, is quite prevalent in dried rice (some sources say ubiquitous), likely as spores."

Bacillus cereus is a bacteria commonly found in soil and food, but some strains are harmful to humans and can cause food borne illnesses.

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Food poisoning occurs due to the survival of bacterial spores. Photo / Getty
Food poisoning occurs due to the survival of bacterial spores. Photo / Getty

Food poisoning caused by these bacteria occurs due to the survival of bacterial spores.

Dr Chapman explained that these spores may survive cooking and if the rice is kept at room temperature after it's cooked, the spores can germinate and multiply.

This is because the environment of cooked rice provides the spores with water and nutrients to grow.

When the spores grow, they release toxins, including one that's heat-stable.

It is not clear how many cases of food poisoning Bacillus cereus causes, but a report by the US Centre for Disease Control sates it's responsible for 2 per cent of food borne illnesses.

However, putting leftover rice in the fridge soon after it's cooked could help eliminate this risk.

According to a study published in the journal Epidemiology and Infection, boiled rice should "either be kept hot (>63C) or cooled quickly and transferred to a refrigerator within two hours of cooking.

"Boiled or fried rice must not be stored under warm conditions especially in the range 15-50C."

In this room temperature range, the bacteria have the ideal conditions to multiply.
Because of this, it's advisable to be careful where you eat.

Dr Donald Shaffner, a food scientist at Rutgers University, told Lifehacker that some restaurants "cook up a large batch of rice, hold it at room temperature all day" and use it when needed, which can lead to food poisoning outbreaks.

However, sushi rice contains vinegar which makes the rice more acidic, meaning it can be kept safely at room temperature.

The best way to prevent this type of food poisoning is to refrigerate rice leftovers within two hours of cooking.

What not to reheat in the microwave

Celery, Spinach and Beets:

Reheating these vegetables can turn the nitrate within them toxic, which are carcinogenic.

Mushrooms: The proteins in mushrooms can break down immediately after they are cut. If prepared mushrooms are stored in the fridge for no more than 24 hours, it's safe to eat them after they're reheated to a high temperature.

Chicken: The protein in chicken changes when cold chicken is reheated, which can lead to digestive problems unless it's reheated to a very hot temperature.

Potatoes: Potatoes can host a bacteria called Clostridium botulinum, which can cause botulism, if they aren't refrigerated soon after they're cooked. Botulism is a rare illness that can lead to paralysis.

Boiled eggs: If eggs aren't heated for long enough, they can cause food poisoning. Cooked eggs should never be left out of the refrigerator for more than two hours because illness-causing bacteria can grow on them.