Let's analyze the rice in the rice cooker in detail as follows:

First case: After the rice is served or even the rice cooker has not been opened, most of the bacteria are destroyed. If the lid of the rice cooker is not opened, the bacteria will not be able to enter. Although the water and nutrient content in rice is suitable for bacterial growth when the power is turned off and the temperature drops, the bacteria will not grow due to lack of bacteria. In this case, the rice will not spoil if left overnight or even worse.

Second case: After the rice is cooked, open the lid to take a little while it is still hot and then close the lid again. At this time, the temperature inside the rice cooker is still relatively high, although some bacteria may enter when the lid is opened, but the rice can be maintained at a higher temperature for a period of time after the lid is closed. During this period, it will have a significant killing effect on the bacteria introduced. After the temperature drops, there won't be too many bacteria left and they won't grow much overnight, so there won't be any problems in general.

In the third case, although the rice has cooled down when it is brought out, the spoons and utensils in the house are still clean and very few bacteria have entered. After one night, the bacteria will not grow much, so it is not a big problem.

The fourth situation is that the leftover spoon of rice has more bacteria, or the pot has more bacteria, using rice in a cold electric rice cooker will create more bacteria. If the room temperature is more suitable for bacterial growth (such as summer), the possibility of these bacteria causing spoilage is relatively high.

Simply put, the first and second situations are basically no problem, but it is not easy to judge the third and fourth situations. From a cautious point of view, it is best to put rice in the refrigerator to control the growth of bacteria through low temperature.