Heating food for a long time at high temperatures will kill harmful bacteria. But you cannot judge if food is cooked completely by looking at its color. Experts advise people to use a thermometer when cooking. Food thermometers measure the exact temperature of the food being cooked. They help guarantee that food is cooked to a safe temperature.
Thermometers also can prevent food from being cooked too long and becoming too dry.
Keeping food at an unsafe temperature also can lead to food poisoning. Some foods left outside in warm weather for more than two hours may not be safe to eat. Experts say such foods should be kept in containers with ice to keep them cold. And, foods should be kept in the coolest part of a vehicle, away from sunlight, whenever possible.