Will rice spoil overnight without opening the lid

Whether rice will spoil if left uncovered overnight depends on the ambient temperature and storage conditions. Bacteria are prone to breed in high temperature and humid environments in summer, and may be well preserved in low temperature and dry environments in winter. In environments where the room temperature exceeds 25 degrees Celsius, rice exposed to air is prone to bacterial contamination, especially heat-resistant bacteria such as Bacillus cereus, which may proliferate. The toxins produced by these bacteria are difficult to completely eliminate even when heated, and may cause gastrointestinal discomfort such as vomiting and diarrhea after consumption. If overnight rice becomes sticky, has a changed taste, or has abnormal color, it indicates that it has spoiled and needs to be discarded. The insulation function of a rice cooker can delay spoilage, but continuous insulation can accelerate moisture and cause a deterioration in taste. In winter or environments below 20 degrees Celsius such as air-conditioned rooms, covered rice has slower microbial growth and can usually be stored for 8-12 hours. Seal and refrigerate with clean utensils in a timely manner, which can extend the freshness to 24 hours. Before re consumption, it is necessary to thoroughly heat it to a center temperature of 70 degrees Celsius or above, but repeated heating can damage the B vitamins. It is recommended to make it in moderation to avoid excess. Regardless of the storage method, the nutritional value of overnight rice will decrease. After starch aging and retrogradation, the glycemic index decreases, but the digestion and absorption rate synchronously weakens. It is recommended to judge the condition of rice based on the environmental temperature and humidity, and prioritize fresh cooking when there is a high risk of spoilage. Daily can be paired with vegetables and fruits rich in vitamin C to help reduce the potential harm of nitrite. Special populations such as pregnant women, infants, or those with weakened immunity should avoid consuming any overnight staple foods.