At that stage, the final quality of all the work the producer has done with raw materials, processing and packaging will be dependent on how well the cold chain can be maintained. Most producers will determine the best-before date of their product in a constant temperature and deduct some time for errors in the cold chain. Temperature checks at each arrival point are meant to verify that the stipulated best-before date can still be trusted. But how do you take into account the temperature abuse between check points.

It stops at the retailer

Normally, the definition of a supply chain is from producer to retailer. Storage by the retailer, consumer handling of the goods to the home and the quality of in-home storage of course has a high influence on the total temperature load of the product. The reason for neglecting this part is that it is virtually impossible to track accurately this part of the chain today. Some have tried with so called TTIs (colour changing indicators) but there is a certain resistance amongst retailers regarding the effectiveness of these. Long-term, this or similar technologies will enable monitoring of the complete supply chain, ultimately giving the consumer a better feel for the accuracy of the best-before date printed on the package.
 
A vision for the future
 
In the meantime, focus has to be on maintaining the correct temperature in the supply chain we can monitor. And it starts in the production facility. Chilled and frozen products are often packed and palletised in an ambient environment, before being put into cold storage. And palletising means adding more labels for traceability purposes as well as shrink-wrapping the pallet. This might take up to several hours in case the SOPs are not working properly for some reason. Once in storage, there is rarely a problem. But each cross-docking point offers a potential danger. A lorry delivering 24 pallets will off-load all of them at once into a reception room. This room will have a cold temperature in some cases and ambient in others. In any case, the time for transferring the first pallet into storage could differ over an hour from the last pallet on the dock, with all the readings and controls that have to be made. And with increasingly complex supply chains, the number of cross-dockings will increase for a lot of products. Adding all this up will certainly add temperature abuse above the specified limit and render invalid the best-before date.
 
One advantage with monitoring the accumulated temperature load is that the focus could be on reading at the end of the chain only, thus avoiding the existing control costs in the chain. Only if the temperature load is too high could controls be initiated at the earlier points. The costs - and unnecessary temperature abuse due to long procedures - could be lowered with this kind of approach.