What Is Fried Rice Syndrome? TikTok Draws Attention to Dangers of Reheating Leftover Rice

Leftovers are an essential part of many people's refrigerators, but there's one item you've been storing and reheating later that you might want to consider ditching. A recently viral TikTok drew attention to the bacterial dangers reheating rice, a common activity that many were shocked could be deadly.

The phenomenon is known as reheated rice or fried rice syndrome. "The danger isn't really in the reheating part; it's in that precarious time between the cooking and the storing that I always love to talk about," explained Food52 in their TikTok video. "The problem is in the type of bacteria that grows in leftover rice. It's called bacillus cereus, or B. cereus for short."

"It's actually heat-resistant," Food52 warned of the bacteria. "Essentially no amount of reheating, nuking, microwaving, steaming, whatever is going to save you if that bacteria did happen to grow in your rice."

"Rice, because it has a high water content, is really really prone to growing bacteria, so there's just a really high chance that in the short time—should be short time—between you cooking and storing your food in the refrigerator that the rice has probably started to grow those spores," they explained.

As for what can happen to you, it's not exactly pretty. "The symptoms of this kind of food poisoning are just really nasty," they said. "A lot of people equate it to botulism symptoms and hospital workers say it's some of the worst cases of food poisoning they've ever seen. It can lead to death."

If you want to avoid being taken out by bad grains, just try to stay away from leftover rice as much as possible. "Basically, if you are not storing your rice within the hour of you cooking it, storing it in the fridge in a totally sealed container, and then only reheating it once the next day—you can only eat it the next day—just throw it away," Food52 advised. "Just throw away your leftover rice, friends. It's really not worth it."

The videos brought the issue to social media users' attention, but scientists have known about the dangers that Bacillus cereus can cause for many years. Research published in 2022 and shared by the National Center for Biotechnology Information outlines the different symptoms associated with B. cereus—namely, diarrhea and vomiting—and their connection to certain foods.

Vomiting, or emesis, is "most often associated with rice products, but it has also been associated with other types of starchy products such as potato, pasta, and cheese," scientists said. The researchers went on to explain what happens after eating bad rice and just why this bacteria is so strong. "Symptom onset is generally within 30 minutes to 6 hours of consuming rice or starchy foods left at room temperature, even after being reheated. This illness is due to the presence of cereulide, an ionophoric low-molecular-weight dodecadepsipeptide that is pH-stable and resistant to heat and proteases," they said.

Another study published last year in the Foods journal explored this phenomenon with rice specifically. Just as the TikTok mentioned, the bacteria's heat resistance makes it a dangerous agent that can easily survive being warmed up in the microwave.

"The inevitability of the contamination of raw rice by B. cereus spores and the violation of time–temperature control and poor hygiene in food preparation and handling are very common, and such practices have resulted in foodborne outbreaks," the researchers said. "The results of this study confirm that the domestic cooking process of rice is insufficient to inactivate the spores of B. cereus."

You might want to start making your rice fresh every day instead of meal prepping and storing it for the week.