The Vice of Rice
How the economics of rice making is probably bad for your health
By Saipriya Shahi
Ever cooked a bulk of rice and left it to sit on your kitchen counter to have as leftovers with takeaway a day or two later?
Yes? Well you shouldn’t have!
Rice, a staple food in many countries around the globe. Known for its versatility serving as a base in numerous dishes from curries and stir-fries, to sushi and even puddings. With an annual consumption of 477 million metric tons around the world in 2017, this rate does not seem to have a decline in site.
Rice is considered to be a great source of carbohydrates and protein, and seems pretty straight forward to cook. Boil some water, chuck in some rice and let time run its course. But you might be making a mistake. A simple one. But big enough to send the entire family to the hospital if things go astray.
Technically the issue isn’t with the cooking of the rice, it’s what you do after that could deteriorate things. Uncooked rice can comprise of spores of Bacillus cereus –a bacterium capable of causing food poisoning. The spores are heat resistant therefore can survive when rice is cooked.
The high heat while boiling the rice may destroy the bacterium, but leaves the spores. So when rice is left on the counter at room temperature to cool down for various hours, it provides the spores with optimum conditions to become activated where they grow into the bacteria, multiply some more and produce toxins. These toxins are strong enough to send you running with a case of vomiting and diarrhoea. All within 1-5 hours post consumption.
Basically, the longer the cooked rice sit out at room temperature, the higher the chances of bacteria growth and the higher the chances they are unsafe to eat.
But what should you do you may think? Well simple! The moment the rice is cooked, eat it, and if any are left, store them in the fridge right away. It’s important to cool any leftovers as soon as you can, possibly within the hour since they were made. But that doesn’t mean keeping them stocked in your fridge for days to come will mean no bacteria growth. If they are over a day old, it’s time to toss them.
Now another factor to take into careful consideration would be when you decide to reheat the leftover rice for later consumption. An easy way out we all take it putting it in the microwave oven and let the machine do its thing. That is the most convenient method in this day and age after all, but it doesn’t guarantee a job well done.
"A microwave may not heat your food evenly so the cold areas are the area of concern capable of causing food poisoning within a short while."
According to science journalist Michael Mosley, “Microwaves create hot spots and dangerous cool spots in your food…and in the cool spots, bacteria can thrive.” So basically, a microwave may not heat your food evenly so the cold areas are the area of concern capable of causing food poisoning within a short while. The precaution you can take to fix this; heat your rice and stir it, and heat it again. Your rice should be steaming hot before you can be satisfied of its safety. But, another but in this case, sorry, just remember not to reheat rice on more than one occasion.
“The temperature of reheating is roughly at 75 degrees Celsius, enough to kill most bacteria except for some, and unfortunately, the Bacillus cereus pathogen lives in rice regardless.”
Just to get a little technical, the rice when placed in the fridge is at approximately 5 degrees Celsius which isn’t ideal for the spores to grow. The temperature of reheating is roughly at 75 degrees Celsius, enough to kill most bacteria except for some, and unfortunately, the Bacillus cereus pathogen is the one which lives in rice regardless.
But if left out at room temperature and allowed to cool slowly, these heat resistant spores and toxins will form, and once formed, reheating cannot destroy them. So it’s better to prevent them from forming in the first place.
Now rice isn’t the only food which these pathogens thrive on. Essentially anything starchy e.g. leftover pasta, noodles, even starchy vegetables like potatoes aren’t safe from these pathogens. And neither are you if you aren’t careful.
So what do you do? Make a smaller quantity initially so there isn’t a need to take extra precautions later on. And if you have enough for left overs, store it in the fridge within the hour. Then just follow –reheat, stir and reheat or if older than a day toss is away!
Seems like a hassle right now, but going to the hospital is a bigger one, and health should always be considered priority one.
Views expressed are personal.
About the Author
Saipriya Shahi holds a Bachelor’s of Science in Food Science from the Auckland University of Technology. She aims to change the future of food with her innovative yet quality product ideas, while being obsessed with photography on the side.