No, rice should never be left to cool to room temperature! Almost all of us make this mistake after cooking the rice, however, it can be dangerous for your health. Here’s why.
Very often, we cook rice in large quantities, so as to have leftovers. But if these leftover rice have been poorly stored, they can quickly lead to food poisoning. Indeed, after having cooked the rice, we generally close the lid of the pan and then let its contents cool to room temperature. We end up placing the rice in the fridge, several hours, even a whole night after cooking. Only here, during this time wisely elapsed at room temperature, bacteria found in rice releases dangerous toxins.
Rice hides a little-known bacterium: Bacillus cereus. It is a bacterium that is naturally present in the environment (earth, water, plants) and some of its strains are natural contaminants of rice fields. It is therefore not surprising that rice is at the top of the list of foods most frequently contaminated by this bacterium. Unlike the well-known salmonella and listeria, this one shows up very resistant to cooking. Reheating rice that is already cooked and poorly preserved would not be enough to save you the day. If the rice is eaten immediately after cooking, there is no risk of contamination. It is only if the rice has been cooked, then stored at room temperature, that the bacterium becomes dangerous: it releases toxins that can cause vomiting, diarrhea and abdominal cramps. If these symptoms generally disappear on their own 12 to 24 hours after consumption of the contaminated rice, we would gladly do without them.
So this is it the right rules to follow to avoid this: place your leftover cooked rice in small containers in the fridge immediately after cooking (the temperature must be below 10°C) and when you reheat the cooked rice, prefer a very high temperature (74°C at least ), it’s the perfect opportunity to make fried rice! In all cases, beyond 24 hours, do not eat these leftovers!