Maintaining temperature control for fruits and vegetables in transit is the most critical factor in assuring successful transport so consumers can enjoy fresh produce at its top condition, flavor and nutritional value.
Yet in the global transport of perishable goods, the “cold chain” that stretches from point of harvest to point of sale can be thousands of miles long with many players participating in the process. With each perishable item having its own distinct optimum temperature and tolerance for temperature fluctuations, how can temperature control for quality assurance be maintained? Considering the volume of goods successfully shipped every day, it’s both complicated and a modern marvel.
The cold chain must be an integrated process where all players recognize their own role as well as those of the previous and subsequent players. This is necessary to assure compliance.
Preparations and Precautions
The packing plan is where the cold chain begins. Products need to be cooled as quickly as possible after harvest to remove the heat load accumulated over the many weeks of growing in the field or orchard. Packing plant personnel must process, cool and pack the produce quickly, avoiding delays of even a day. At no point, should there be mixing of cold and warm products.
Before transport, products should be pre-cooled to their minimum safe temperature to ensure all biochemical and physiological processes are slowed down and to guarantee enough potential postharvest life to endure transport and commercialization at destination markets. Most efficient and effective ways to pre-cool fresh produce involve very cold water, forced air or even vacuum, depending on the type of commodity.
The Journey Begins
If produce is loaded into refrigerated containers or trucks using non-refrigerated cross docks or loading stations, the container’s refrigeration system should not be running while loading, as warm air from the surroundings will likely be introduced into the container.
When fresh produce arrives at destination ports, it either goes directly to distribution centers or ripening facilities in the same containers, or it is transferred to refrigerated trucks and then hauled.
Keeping it Cool
Up to this stage of the perishable commodity’s journey from farm to fork, the “heavy lifting” of temperature control has been largely handled by a container refrigeration system. Now, nearing the final destination, the perishables will leave the security of the container and may be subject to unintended breaks in the cold chain as they get closer to the “finish line” of the consumer’s shopping cart.
If fresh produce only spends a short time at distribution centers before being dispatched to stores and supermarkets, it may not suffer negative consequences from being kept at temperatures too high or too low. However, if these goods are staged at suboptimal temperatures for even several hours, then deterioration, ripening or chilling injury can be triggered.
After being staged in distribution centers, fresh produce will be dispatched for stores, supermarkets and wholesale markets.
Fresh on Arrival
Once fresh produce arrives at stores, supermarkets and wholesale markets, it will often be commercialized at warmer than optimal temperatures. Typically, stores and supermarkets maintain ambient temperatures between 68 and 75 degrees Fahrenheit for the comfort of shoppers. Unless stores have the space and equipment to create refrigerated storage areas kept at different temperatures, backroom staging of fresh produce tends to range between 50 and 90 degrees Fahrenheit.
Fresh produce usually remains on shelves between one and five days before final sale. Managing fresh produce display areas is a constant battle against time and spoilage (over-maturity), where produce managers work to keep shrink levels low.
Exposing fruits and vegetables to suboptimal warmer or colder temperatures during distribution and commercialization will undermine quality, condition and shelf life potential.
We have technology that is better than ever to maintain temperature compliance. The rest is up to those who manage the distribution process so that consumers can enjoy fruits and vegetables that seem freshly picked, even when the originating farm or orchard is half a world away.
Eduardo Kerbel joined Carrier Transicold Global Container Refrigeration in 2015, building on a 29-year career focused on postharvest business practices for private industry and government and as an educator.