Buzz
Do you enjoy eating rice? Do you sometimes store it in the fridge for later? I do too! These are all common, relatable habits. However, there’s been a recent uproar on social media warning about the supposed dangers of consuming rice that’s been sitting around for days. While these warnings are mostly exaggerated, there is a bit of truth to the caution.
Yes, reheated rice is safe to eat
I’ll begin by sharing the conclusion, then we’ll dive into why this is the case. Those who claim that you should never keep leftover rice or suggest that reheating rice could be fatal are either misinformed or are vastly overstating the risks involved.
Reheated rice is safe to eat as long as it hasn’t spent too much time in the danger zone. The danger zone is between 40 and 140 degrees Fahrenheit – warmer than a fridge but cooler than cooking temperatures. Two hours is the safe time limit, and this rule should apply to all your cooked, perishable foods.
If your rice made it from the rice cooker (or stovetop) to the fridge within that time, you’re in the clear. Your rice will last for several days, just like other leftovers. However, if you leave rice out on the counter for hours while you eat, clean, or get distracted… well, how long has it been sitting there? In that case, you should throw that rice away.
The potential for food poisoning from rice
Food poisoning is caused by microorganisms, like bacteria, or by the toxins they produce. While many germs can thrive on rice, the main culprit behind most concerns is Bacillus cereus (B. cereus for short). Fun fact: “cereus” comes from “cereal,” even though this bacterium is found in soil and can contaminate nearly any food, rice is its most notorious home.
Like other bacteria, B. cereus can exist as living bacterial cells that feed off the nutrients and moisture in your food. So far, nothing unusual. But B. cereus is one of the few foodborne bacteria that forms spores, which can be likened to eggs for the next generation. These spores are heat-resistant, meaning that even if you cook the food and kill off the adult bacteria, the spores remain. In fact, the cooling process after cooking activates them to germinate, starting the growth process immediately.
While B. cereus bacteria are multiplying, they can produce a toxin known as an emetic toxin, which is a poison that induces vomiting. This toxin is responsible for the condition commonly referred to as “fried rice syndrome” or “reheated rice syndrome” that’s often blamed on leftover rice.
To summarize, the key difference between B. cereus and most other food poisoning bacteria is that heat does not eliminate the vomit-inducing toxin. Normally, reheating leftovers to 165 degrees (or “until steaming” or “until piping hot”) makes them safe. However, B. cereus scoffs at that microwave treatment. The best way to avoid B. cereus making you sick is to stop it from growing in the first place, and then remember to kill it off.
But can B. cereus actually kill you?
Food poisoning from B. cereus in leftover rice may cause vomiting, but it’s very unlikely to lead to anything more severe. A typical case of emetic B. cereus lasts less than 24 hours and involves nausea, vomiting, and stomach cramps. It’s unpleasant, and certainly not something I recommend experiencing. However, the extreme warnings about leftover rice sending people to the hospital are exaggerated.
There are two types of food poisoning you can get from B. cereus: the type associated with rice and starchy foods, which we’re discussing here, and a diarrheal form that is more commonly contracted from meat, vegetables, and dairy products.
Taking both of these into account, the CDC estimates that between 2000-2008, there were approximately 63,000 cases of B. cereus food poisoning annually, with 20 hospitalizations and no deaths. This means only about one-third of 1% of cases required hospitalization, and there were no fatalities. While this doesn’t mean deaths are impossible, it does show that the extreme warnings from TikTok lack significant perspective.
B. cereus can cause severe illness and even death, but not in the form associated with food. The NIH has a publication for healthcare professionals here, explaining the various types of B. cereus infections, including their complications and risk factors. The more serious cases are linked to bacteria introduced through injuries, intravenous drug use, or medical devices like central lines and pacemakers. (Remember, this is a soil bacterium, so people get this type of infection through contaminated wounds.) There are also B. cereus infections that start in the eyes, often following eye injuries. Medically significant: yes. Found in bowls of refrigerated rice: no.
How to store and reheat rice safely
As we’ve mentioned earlier, rice is safe to reheat (or eat cold), as long as it’s been handled correctly from the start. Let’s walk through the important details.
And by the way: While I love being your trusted source for debunking the science behind online rumors, please keep in mind that the USDA offers extensive food safety resources online, as do many university cooperative extensions. These are far more reliable than TikTok, blogs, or even major media outlets. Food safety experts specialize in this because it’s their job.
Let’s dive into this publication from the USDA and the University of Florida’s Institute of Food and Agricultural Sciences, which explains how to prevent foodborne illness caused by Bacillus cereus. Does it recommend throwing out your rice? No! It actually says:
To destroy the vegetative (actively growing) cells, cook the food to ≥ 145ºF (63ºC) and reheat it to 165ºF (74ºC) for at least 15 seconds.
Once the food is cooked, quickly cooling it will prevent spores from germinating. However, keep in mind that food cannot be made safe if toxins have already been created.
To prevent spores from forming, keep hot foods above 135ºF (57ºC) and cold foods below 41ºF (5ºC). • Properly refrigerate leftovers by cooling them rapidly to 41ºF (5ºC) or lower. Avoid stacking containers too closely together to allow proper airflow and ensure faster cooling.
They don’t give a specific duration for what counts as “rapid” cooling, but elsewhere they mention guidelines that suggest food should not sit out for more than two hours.
A rice cooker set to the “warm” setting usually sits around 150 degrees Fahrenheit, which means, while it may sound unappealing, rice left on this setting for hours is likely still safe to eat. However, if you do this frequently, it might be a good idea to use a thermometer to ensure your rice cooker maintains a temperature high enough to keep the rice out of the danger zone.
How long can you store rice in the fridge if it was initially handled properly? There isn’t a specific recommendation just for rice, but the general guideline for cooked food is to store it for no more than 7 days, provided it stays below 41 degrees the entire time. (Your fridge should be set well below 41ºF to keep food safe and extend its shelf life. The ideal temperature is in the mid-thirties, as 32ºF is freezing.) While the 7-day rule applies to restaurants, the general public is advised to store leftovers for no more than 3 to 4 days instead.
For reasons I don’t fully grasp, some sources from the United Kingdom (such as this from the NHS) suggest refrigerating rice for no more than one day. However, U.S. guidelines align more with the University of Florida’s stance. A food safety expert from the University of Wisconsin-Madison says leftover rice, if handled properly, can be stored for three to five days (and mentions that a cold rice salad is one of her go-to lunches). The University of California shares a similar viewpoint in their own rice safety publication, also recommending three to five days. I’ll follow their guidance instead of the TikTok panic, and continue enjoying my leftover rice.
