As the name suggests, the incubator is to maintain the inherent temperature of your food. If the food goes rancid, bacteria will breed (the temperature at which bacteria breed in food is 15-35°C. The higher the temperature, the more likely it is for food to deteriorate). If you put the lunch box in, it will not go rancid easily if the temperature is relatively high (above 65°). Or you can cool down the lunch box, wrap it in a plastic bag with ice cubes and put it in, so the food will not go bad easily