Rice Reheating Mistakes That Could Make You Sick

Many people prepare extra rice and save it for later meals. While this is practical and convenient, improperly stored rice can pose a health risk.

Cooked rice may contain spores of Bacillus cereus, a bacterium capable of surviving the cooking process. If rice is left at room temperature for too long before refrigeration, these spores can multiply and produce toxins. Importantly, reheating rice does not destroy these toxins once they have formed.

Health risks
Consuming contaminated rice can lead to food poisoning, typically causing nausea, vomiting, and diarrhea. Symptoms usually appear within 6 to 15 hours and often resolve within 24 hours. Although generally not severe, these symptoms are unpleasant and preventable.

Scientific studies have confirmed this risk. For example, research published in the journal Foods (MDPI, 2023) found that Bacillus cereus spores can survive cooking and rapidly grow when rice is stored at warm temperatures (25–30 °C). In contrast, refrigeration at 4 °C effectively prevented bacterial growth for up to seven days. This reinforces the importance of rapid cooling and cold storage as the best line of defense against contamination.

Safe storage practices
Health authorities, including the UK’s National Health Service (NHS), recommend the following guidelines to minimize risk:

• Cool rice quickly and refrigerate it within one hour of cooking.

• Divide into smaller portions to speed cooling.

• Store below 5 °C (41 °F).

• Do not refrigerate rice while it is still hot—allow it to cool slightly first.

• Consume refrigerated rice within 24 hours.

• When reheating, ensure it reaches at least 74 °C (165 °F).

Rice itself is not toxic. The danger arises when it is stored improperly. Proper refrigeration and reheating practices can prevent the growth of harmful bacteria and reduce the risk of foodborne illness.