What are Time-Temperature Indicators?

When global distribution systems for food began to be widespread, issues surrounding the temperature tolerance of some foods began to surface, with some packaged goods being inedible by the time of delivery. Time temperature indicators are used in food packaging to indicate the freshness and safety of a product. They are designed to assist in stock rotation, consumer identification of food which is safe to eat, and in the monitoring of food supplies. Time temperature indicators are relatively inexpensive, and began appearing on some food products in the late twentieth century.

Time temperature indicators take a crucial factor which affects food safety into account. The longer food is kept in poor conditions, which could be extreme heat, freezing, or both, depending on the product, the more likely it is to experience damage which could result in making it unsafe to eat. Many companies warehouse packaged food for months at a time, potentially exposing it to extreme temperature conditions. Usually, if food has been exposed to dangerous temperatures, it becomes apparent after the package has been opened. However, this is not always the case, and it is also an inefficient way to detect potential damage to the food.

Time temperature indicators show interested parties when a food has been in a potentially hazardous temperature situation. Some foods, for example, should not be frozen, and will use a temperature indicator to show that the food has been handled or stored improperly, causing it to freeze and potentially be inedible. Other foods are sensitive to heat and use temperature indicators to show that the food has been compromised.

Time temperature indicators allow manufacturers to trace their foods along the supply line, and consumers to feel confident about what they are purchasing. These indicators usually take the form of a small badge which is adhered to the exterior of the packaging. Time temperature indicators usually have a clear bar which will fill with color as the food is exposed to an unsafe temperature. If removed from the poor conditions, the bar will still be colored in, showing that the food was exposed, and the duration of the exposure. Another type incorporates a circle which slowly darkens as the food is kept in hot conditions.

External indicators are also highly useful, allowing personnel to quickly and accurately evaluate the safety of foods. In some cases, a minimal exposure to poor temperature conditions may not be harmful, and the food is safe to eat, although it may not be of optimal flavor. In others, it should be discarded. By checking food as it moves through the supply chain, companies can identify and address areas of weakness. Consumers at home can be certain that they are keeping their food in a healthy temperature range with the assistance of time temperature indicators, while organizations such as the military use them to monitor rations.