The Big Chill

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Modern technology makes temperature-controlled transport so easy that we can now enjoy virtually any kind of fresh fruit or vegetable, and many other food items, year-round.  Since many fresh, unprocessed products have a limited “shelf life” at room temperature, these commonly move internationally as chilled or frozen shipments to extend their useful commercial life.

Some food items, including many types of fresh fruits, vegetables, and mushrooms, can remain in good condition for up to several days at room temperature, but much longer in a cool but above-freezing environment.  Many such products can be transferred from one cool location to another, with relatively short periods at room temperature during that transfer, without significantly affecting product quality.

More sensitive items, including many types of meat, egg, and milk products, require a more consistent temperature to maintain optimum quality.  Many products have been found to keep best at a specific temperature, which may be either above or below freezing.  A few examples of ideal storage or shipment temperatures, in degrees Fahrenheit, are:

  •  fresh apples – 30 to 40 degrees

  •  most types of fresh berries – 31 to 32 degrees

  •  fresh watermelon – 50 to 60 degrees

  •  most fresh meat and poultry products – 40 degrees or below

  •  most frozen meat and poultry products – zero degrees or below

  •  frozen crab – minus 13 degrees or below

For transport of these more sensitive food products, international air and ocean carriers have developed solutions including:

  •  temperature controlled ocean containers with mechanical refrigeration units that can be set to keep their contents at a specific temperature, either above or below freezing (commonly known as “reefers”)

  •  “reefer” ocean containers which also provide “controlled atmosphere” during transit, to slow down the fruit and vegetable ripening process, and further extend shelf life

  •  use of “dry ice” or chilled / frozen “gel pacs” to maintain air freight packages or air cargo containers within a desired temperature range

Ocean container mechanical refrigeration units are electrically powered, and loaded “reefer” containers are normally plugged in to power outlets while in a marine terminal or on board ship.  When this type of container moves by truck or rail, the refrigeration unit is typically powered by an internal combustion engine-powered generator set (commonly referred to as a “genset”).  Some types of gensets can be mounted directly on the upper front part of a reefer container, while others attach to the chassis that the container sits on.

To ship food products that will benefit from a controlled temperature environment during transit, shippers and consignees should:

  • know the optimum storage temperature (and type of atmosphere) for the type of product being shipped

  • when possible, avoid mixing products with different temperature and/or atmosphere requirements in the same container

  • pre-cool both the ocean container and the cargo to the desired temperature, before loading the cargo into the container

  • for high-value products, consider placing temperature recorders in the shipment, to maintain a record of any changes in temperature during transit

  • stow cargo packages within the container in loading patterns that create airways along the sides and through the interior of the shipment, to facilitate even circulation of chilled air to maintain an even temperature through all parts of the load

  • verify correct temperature settings before releasing the loaded container to the carrier

  • upon receipt of the container at destination, verify:

    • container seal is intact

    • refrigerating unit temperature is correctly set

  • upon opening the container door, verify:

    • actual temperature of the product

    • if temperature recorders are used, they are positioned in the correct locations within the shipment, and have actually recorded shipment temperature during the entire transit period

For air cargo:

  • confirm with your freight forwarder or carrier whether “dry ice” is allowed for this combination of carrier and routing

  • use a sufficient amount of “dry ice” or gel-packs to keep the product at the desired temperature for the entire transit time, plus any additional time that may be required for customs clearance, plus an additional margin for potential delay in transit

  • arrange the dry ice or gel-packs within the outer package, to provide full coverage for all sides of the inner package that contains the product

For any shipments of refrigerated or frozen cargo, from one-carton sample shipments to full marine containers, your freight forwarder and customs broker can provide valuable advice on how to get your product to its destination safely, and remain in good condition.  Transmark Customs Brokers and its service partners routinely handle a broad range of temperature-controlled products, both export and import, and are always ready to share the benefits of their experience with you.