How long should you leave cooked rice unrefrigerated?
Last week a friend sent me an urgent text. Due to a miscommunication with her babysitter, a full pot of rice, veggies, and black beans sat on the counter all day. When my friend got home from work, she found the pot still unrefrigerated. Tired, she was loath to throw out what was supposed to be that night’s dinner.
It was an appetizing and healthy one-pot meal. No doubt having a 2-year old watching her every move added to my friend’s sense that starting from scratch was a much-less-than-ideal solution. What should she do?
The short answer is that she absolutely should throw it out. Leaving cooked rice unrefrigerated all day is dangerous, especially for small children and those with immune-compromised systems.
Why shouldn’t she feed her family the room temperature food that had been left on the counter, even though it smelled and looked fine?
It’s unlikely she would kill any of them. However, feeding her kids rice and beans left unrefrigerated for hours would might well sicken them in a rather unpleasant way. The culprit would be bacillus cereus. Even if your eyes are glazing over at this point, listen up if you cook – or just eat – rice.
Most people associate foodborne illnesses with meat or fruits and vegetables. However, rice can also be a source for food poisoning.
Uncooked rice can contain spores of bacillus cereus and those spores survive cooking.
When rice cools slowly (i.e. you leave it on a counter to cool instead of being put into the refrigerator within 2 hours), the bacteria spores grow and produce a toxin that can make you sick.
Reheating the rice won’t kill those spores.
For most adults, food poisoning from cooked rice contaminated with bacillus cereus subsides within 24 hours without serious or permanent injury. However, it may more severely affect those with compromised immune systems and young children.
If you’re interested in the specifics of how the bacteria does its nasty work, check out the FDA’s appropriately-titled Bad Bug Book.
We don’t live in a perfectly safe world and you can never totally avoid all risk of food poisoning. But here are some tips to keep you healthy.
Tips to Help Minimize the Risk of Sickness from Cooked Rice
- Once you cook rice, cool any leftovers (including dishes containing rice) quickly and refrigerate them. Ideally refrigerate it within 1 hour, though some authorities say within 2 hours is OK. When refrigerating a large quantity, transfer the rice into a clean, cooler container. Using a wide container helps too. The rice cools more quickly if you spread it in a thinner layer, rather than leave it piled up.
- Refrigerate rice only for a short period of days at or below 40 degrees F. According to numerous food safety experts, you should only refrigerate cooked rice for 1 day. I have kept rice for 4-5 days, the storage time considered allowable by the USA Rice Federation. But after researching for this post, I’ll try to use or throw away (refrigerated) cooked rice after 1-2 days.
- Reheat cooked rice only once.
Now that I’ve spent several hours researching rice and food safety, I’m in a bit paranoid.
Intellectually, I know there isn’t bacteria in every pot of rice I make or serve. Still, I can’t help feeling like a medical student who gets every disease they read about.
So, to ease my mind, I’m going to re-read this wonderful piece from Harold McGee on sensible, real world balancing of risk and cooking reward.