Bacillus cereus from rice: Symptoms, Prevention, Treatment

Bacillus cereus is a type of bacteria commonly found in soil, dust, and various types of food, including rice. While this bacterium is generally harmless, it can cause food poisoning when present in large quantities. 

Ingesting food contaminated with Bacillus cereus can lead to symptoms such as nausea, vomiting, and diarrhea. 

Rice is particularly susceptible to Bacillus cereus contamination due to its ability to grow and reproduce quickly in warm and moist environments. 

We will explore the various ways in which Bacillus cereus can contaminate rice and discuss effective methods for preventing its growth and spread.

What is Bacillus cereus

bacillus cereus in rice

Bacillus cereus is a type of pathogenic bacteria that can cause food poisoning. This bacterium is commonly found in the soil, dust, and some foods, including rice.

When cooked rice is left out at room temperature for an extended period, B. cereus can multiply and release harmful toxins, which can lead to food poisoning in individuals who consume it.

This bacteria is able to form spores that can survive the cooking process, allowing it to potentially grow and multiply if the food is not handled or stored properly.

How common is Bacillus cereus in rice?

Bacillus cereus is a relatively common bacteria found in rice. The bacteria can contaminate uncooked rice as well and the spores can survive the cooking process and grow rapidly if the cooked rice is kept at room temperature for a long time.

Some studies have found that a significant percentage of rice samples are contaminated with B. cereus, and fried rice is known to be a common food vehicle for the bacterium.

Bacillus cereus virulence factors

There are reasons why Bacillus cereus is capable of causing foodborne illness. This ability is due to its ability to produce various virulence factors.

Some of the virulence factors produced by Bacillus cereus include:

  • Toxins
  • Adhesins
  • Hemolysins
  • Proteases
  • Phospholipases
  • Spores


Bacillus cereus can produce two types of toxins, namely diarrheal and emetic toxins. The diarrheal syndrome of food poisoning is caused by the enterotoxins produced in the small intestine, which causes watery diarrhea. 

On the other hand, the emetic syndrome of food poisoning results from the emetic toxin produced by the organism, which causes vomiting. 

These toxins are heat-stable and can survive heat treatment and grow at low temperatures.


Bacillus cereus is also known to produce adhesins, which are microbial components that enable the bacteria to attach to host tissues. 

When these adhesins are produced, they help the bacteria to bind to specific host cells, which allows them to colonize and infect the host. 

By binding to the host cells, the bacteria gain entry into the host and can then start replicating and causing damage to the host tissue. This is a common mechanism utilized by many bacteria to establish and promote infections.


Hemolysins are proteins produced by B. cereus that can cause the breakdown of red blood cells. This process is known as hemolysis. 

When red blood cells are destroyed, the hemoglobin within the cells is released into the bloodstream. 

This can lead to anemia, which is a condition in which there are fewer red blood cells than normal in the body. 

Anemia can cause fatigue, weakness, shortness of breath, and other health complications. 

Additionally, the release of hemoglobin can cause damage to other organs such as the kidneys. 

Therefore, the production of hemolysins by Bacillus cereus can be problematic for human health.


This bacterium produces proteases, which are enzymes that break down proteins.

These proteases can damage host tissues by breaking down proteins in the host’s cells, allowing the bacteria to invade and colonize the host’s tissues. 

This process can facilitate bacterial invasion and can lead to the further spread of the bacteria throughout the host’s body. 

In general, proteases can disrupt the normal functioning of proteins in a host’s cells, which can lead to a variety of negative health effects.


It produces phospholipases, which are enzymes that break down phospholipids in cell membranes. 

Phospholipids are important components of the cell membrane, which is the outermost boundary of a cell that separates the inside from the outside environment. 

When these enzymes break down the phospholipids, it can lead to the destruction or derangement of the host’s cell membrane. 

This can result in cell lysis, complete destruction or rupture of the cell, and tissue damage.

Symptoms of Bacillus cereus rice food poisoning

The symptoms of Bacillus cereus food poisoning vary and may include:

  • Diarrhea
  • Vomiting
  • Abdominal pain
  • Nausea

How to prevent Bacillus cereus in rice

To prevent Bacillus cereus in rice, it is important to follow proper food safety guidelines when cooking and storing rice. 

  • Then immediately stored in the refrigerator below 5°C (41°F). 
  • Rice that has been left out at room temperature for more than 2 hours should be discarded. This is because the bacteria can multiply rapidly at room temperature, especially between 4°C (40°F) and 60°C (140°F), which is known as the danger zone. 
  • Rice should not be cooked in advance and then reheated multiple times, as this can allow any bacteria present in the rice to multiply further. 
  • Instead, the rice should be cooked and consumed on the same day. 
  • If you need to reheat rice, make sure you do so thoroughly, until it is steaming hot all the way through, and consume it immediately after reheating. 

By following these guidelines, you can reduce the risk of Bacillus cereus and other types of food poisoning.

Food poisoning from rice treatment

If you suspect that you have developed food poisoning from Bacillus cereus in rice, it is important to seek medical attention immediately. 

This is because Bacillus cereus can produce a toxin that can cause rapid onset of food poisoning symptoms, typically within 6 to 15 hours of consuming the contaminated food.

Treatment may include: 

  • Rehydration
  • Electrolyte replacement
  • Antibiotic therapy. 

It’s important to drink plenty of fluids to replace those lost during diarrhea and vomiting. In severe cases, hospitalization may be required.

Does washing rice remove Bacillus cereus?

Washing rice does not necessarily remove Bacillus cereus. The bacteria can survive cooking and even sprout back to life which means the bacteria can survive the washing process as well.

Washing rice can help reduce the number of bacteria present but it does not remove all of the Bacillus cereus spores.

Does all rice contain Bacillus cereus?

Not all rice contains Bacillus cereus but it is a common rice found in rice and can potentially grow if the rice is not properly handled or stored.

Rice left out for 3 hours

Rice that has been left out at room temperature for more than two hours can potentially allow Bacillus cereus to grow and produce harmful toxins.

It is important to either eat the rice immediately or store it in the refrigerator or freezer within two hours of cooking to prevent bacterial growth.

Can you eat cooked rice cold the next day?

Eating cooked rice that has been stored in the refrigerator is generally safe as the cool temperature of the refrigerator prevents bacteria from multiplying.

However, to eat it, reheating the rice is necessary. Ensure that it is heated to a temperature of at least 165°F (73.9°C) to kill any bacteria that may have grown on it.

Can you eat cold rice after 2 days?

It is generally not recommended to eat cold rice that has been stored in the refrigerator for more than 2 days because bacteria including Bacillus cereus can potentially grow and cause food poisoning.

What food poisoning do you get from rice?

There are different types of food poisoning that can be caused by rice but one of the most common is Bacillus cereus food poisoning. 

How long does rice food poisoning last?

Symptoms of rice food poisoning from Bacillus cereus typically last up to 24 hours. However, in some cases, symptoms may persist for several days. It is important to stay hydrated and seek medical attention if symptoms persist or worsen.

Does vinegar kill Bacillus cereus?

Vinegar is often touted as having antimicrobial properties but it is not considered an effective way to kill Bacillus cereus.

This is because the bacteria are able to form spores that are able to resist the effects of vinegar.

In fact, the acidic environment created by vinegar may actually promote the growth of Bacillus cereus.

What Next?

If you suspect that you have developed rice food poisoning from Bacillus cereus, seeking medical treatment as soon as possible can help you recover more quickly and avoid potentially serious complications.

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Last Updated on May 2, 2023 by Our Editorial Team