Leftover rice may seem to be at the bottom of the totem pole where food poisoning is involved, but experts say that something seemingly innocuous can cause health threats when stored improperly.
With more than 5 million food poisoning cases in Australia every year, it falls on professionals in the foodservice industry to further their knowledge through food handlers certificate courses. Just the same, those who choose to eat at home will still benefit from proper food storage and preparation.
Leftover rice, while seemingly safe, can still contain pathogens that cause food poisoning under certain conditions.
Pathogens Still Lurk
Food safety specialist Benjamin Chapman says cooking rice doesn’t exactly kill all pathogens that lurk in it. A particular pathogen called Bacillus cereus, in the form of spores is prevalent in dry rice, and these can survive cooking.
By holding cooked rice at room temperature, moreover, spores tend to emerge from their protective form and germinate, allowing vegetative forms to multiply. It also doesn’t help that cooked rice provides the ideal environment for the growth of these pathogens, as they present plenty of nutrients and water for growth. As a consequence of growth, they create toxins, including one that’s stable in heat.
Beyond home-cooked rice, food scientist Donald Schaffner notes that some restaurants practice cooking up a large batch of rice and holding it all day at a room temperature. As Bacillus cereus is a heat-stable toxin, this is not a best practice and has in fact led to outbreaks in the past.
A study estimates that every year, there are about 63,623 cases of Bacillus cereus-related poisoning. Fortunately, proper storage, handling, and preparation can help defeat toxins.
Experts say that popping your leftover rice in the fridge after you eat should help keep it safe. The Epidemiology and Infection, meanwhile, suggests to either keep boiled rice hot (above 145.4°F) or cool it quickly and transfer it inside the fridge within two hours after cooking. When eating out, it also pays to be mindful whether or not they served you freshly-cooked rice.