Storage time and temperature have historically been recognized for their effect on food quality. Perishable food products simply deteriorate more rapidly at higher temperatures. To minimize this loss of quality, it is crucial that food products be protected during storage and throughout the entire distribution path, commonly referred to as the cold chain.
Explore this issueApril/May 2005
The importance of time-temperature controls is increasing in the face of more stringent regulations, new market demands and more consumer awareness. Simple time-temperature indicators (TTIs) may be the best answer. TTIs are cost-effective tools that can ensure and demonstrate cold chain integrity. However, to properly leverage the benefits of temperature monitoring, the relationship between time and temperature and food quality must be better understood.
The importance of time-temperature controls is increasing in the face of more stringent regulations, new market demands and more consumer awareness. Simple time-temperature indicators (TTIs) may be the best answer.
Effective Cold-Chain Monitoring
Although temperature-monitoring tools have improved considerably from the ice cube test, the basic concept remains: Bacteria grow more rapidly on improperly stored food and this can impact food quality. Companies must manage this time-temperature relationship to ensure food distribution channels remain within adequate operating limits.
Successful food companies know the optimum storage conditions for their products. Incorporating this knowledge into food supply-chain management will help ensure that these storage temperature requirements are met. If the cold chain is compromised at any point, food quality can be compromised. Consistent and accurate temperature monitoring must be implemented.
Several methods of temperature monitoring have been developed throughout the years. From in-truck chart recorders that document trailer temperatures to retail case thermometers, the science of temperature monitoring has evolved. One new technique that has been gaining momentum is the use of simple and proven TTIs.
TTIs provide a convenient system to determine the integrity of a product’s cold chain through use of irreversible visual color changes that track the accumulative effect of temperature exposure.
The rate of color change depends on the amount of total heat energy input to the sensor. At higher temperatures, the color reaction occurs relatively quickly. As the exposure temperature drops, the reaction rate, and hence color change, slows.
Usually produced as pressure-sensitive adhesive labels, the TTIs can be somewhat customized to match the time- temperature storage requirements of specific perishable products. The reaction of the TTI must match the particular time and temperature storage curve or common spoilage rate of different foods. This will ensure that a visual change in the TTIs will correlate with a potential change in product quality. TTIs are made in a variety of formulations to account for different food spoilage rates (such as 5- 10- or 15- day shelf life for foods at 35ºF).
Properly selected TTIs can indicate remaining shelf life of a perishable product from the factory to the end-user. The TTIs accompany the products with placement on the packaging to best reflect the condition of the foods. Consumers and retailers can be satisfied by the provision of additional product quality information. TTIs can provide such a solution with convenience and reasonable costs.
Because cost-efficacy and ease-of-use are important, TTI technology is continually evolving, and at least one type now eliminates the need for indicator refrigeration prior to application thus alleviating logistical hassles.
This TTI is comprised of an indicator and an activator label. The chemical reaction will not take place until the two components are joined. This ensures that any indicator changes are a result of a compromise in cold chain integrity, and not improper indicator storage.
Importance of Food Quality
Protecting perishable seafood has always presented one of the most difficult challenges to cold chain management. Some seafood processors, in particular, have been quick to adopt quality controls on the basis of temperature and are using TTIs to track cold chain integrity.