Between 4°C (40°F) and 60°C (140°F) is called the temperature danger zone. Within this temperature range, it is possible for bacteria to multiply rapidly. As food handlers, it is our responsibility to reduce the possibility of this rapid multiplication of bacteria by keeping food out of the temperature danger zone. Foods may enter the temperature danger zone during cooking or food handling at times, but we need to make sure that the food products we are handling do not spend more than 4 hours total within the temperature danger zone. However, it is suggested to keep that time under 2 hours, whenever possible. This time frame includes from the minute the food is delivered to the food service operation, to the time it is served to the customer.
If foods are within the temperature danger zone for more than two hours, the bacteria can multiply so quickly that it can cause an instance of food-borne illness. As a general rule to prevent food from entering the temperature danger zone: keep hot food hot and cold food cold. It is imperative that food spend as little time as possible within these temperature ranges.
The Time/Temperature Factor states that the longer food is in the temperature danger zone, the more bacteria will multiply. Since bacteria are able to multiply faster within the temperature danger zone, if a food is within this temperature range for over four hours, it should be thrown away and never eaten or served to a customer.
The most important tool to use when practicing safe food handling, is a thermometer. This little, magical instrument will ensure that food products are at the right temperature when they are: delivered, stored, cooked, displayed, and cooled. It will also measure the temperature of cleaning and sanitizing solutions. There are many types of thermometers used within commercial food operations, some with specific uses like a candy thermometer. There are also digital read thermometers, analog thermometers and multiple kinds of probe thermometers. After using a thermometer, always clean and sanitize the probe, as well as its sleeve, if it has one. If you find that a probe thermometer is not reading the temperature correctly, it can be calibrated by placing it into a cup of ice water and adjusting the needle manually (depending on the type of thermometer).