Editors note: This is the first in a series of articles written by Eduardo Kerbel for Food Logistics' Cool Insights column.
Whether it is blueberries or bananas, the transport of fresh produce to distant destinations will be considered successful only if the produce arrives well preserved and in optimal quality. This requires far more than simply loading goods into a technologically-advanced refrigerated container, adjusting the temperature and waving bon voyage as it sets sail aboard a modern containership.
When fresh produce arrives at the port of departure, shipping lines trust that it’s been handled by growers and packers in accordance with the best cold chain practices. These are vital to optimizing conditions for shipping and avoiding problems in transit.
Proper harvesting and handling practices are the first critical step to achieving high product quality. Fruits and vegetables must be picked at the right moment, factoring in the time required for transport. Also, handling should not injure the produce, since it can set off a chain reaction of premature ripening in transit.
Criteria, such as harvest age, diameter, maturity, firmness and Brix (sugar content), are important parameters for harvesting and selecting produce. In order for produce to arrive at retail in top condition, growers need to consider the farm-to-fork timespan, including the holding time at the country of origin, transit time on the vessel, and time to deliver and display at retail.
Taking Care at the Packing Plant
Nearly all fresh produce is delicate at harvest, needing protection from direct solar radiation and careful handling both in transport to the plant and while there. Any physical injury can diminish transit life potential and lower quality. The more the produce is handled, the greater the chance for physical injury.
Critical issues at the packing plant are sanitation, water quality and potability, and the avoidance of low quality or infected product into the packing line. Other factors include: adequate selection processes to remove culls and the proper application of appropriate fungicides to thwart the potential spread of disease and decay during transit.
Produce should be processed, packed and cooled as soon as possible on the same day as harvest. Carrying over to the following day can diminish the quality of the perishables and reduce transit life potential.
Proper packing and packaging also are critical. Adequate packaging materials should be used to protect perishables from physical injury. It also should have ventilation for proper pre-cooling. Packaging materials should allow for fumigation treatments for insect-control, depending on the receiving country’s requirements.
Avoiding Breaks in the Cold Chain
Temperature management is imperative for any product to reach its maximum transit-life potential. Handlers should use the fastest and most effective means of pre-cooling for each specific product, bringing temperatures down to the minimum safety level based on guidelines.
Once the desired temperature is achieved, it is important to avoid exposing produce to temperature fluctuations beyond allowable limits for the specific item. Pre-cooled produce should never be mixed with warm produce in the same refrigerated container, as the warmer product will reduce transit-life potential of the pre-cooled product. Finally, recommended temperature settings should be maintained for each type of commodity.
Ethylene is produced by all fresh produce and its presence should be minimized during transit, because it can accelerate ripening, aging, decay, and loss of firmness and texture.
Minimizing ethylene inside the refrigerated shipping container starts at the packing plant. A properly refrigerated and tightly-closed cross dock should be maintained when loading produce into a container. However, if complete closure between container and dock cannot be achieved, the refrigeration unit should be shut off during loading to not draw in ethylene, which can be generated by nearby decaying plant material or emitted in the exhaust of vehicle engines that may be running in the vicinity.
To maximize success in transporting perishables, growers, exporters and shipping lines should work together to clearly define responsibilities and agree upon handling and transport practices, including recommendations for temperature settings, relative humidity and ventilation. Additionally, desired oxygen and carbon dioxide levels should be communicated if technologies such as Carrier Transicold’s XtendFRESH™ controlled atmosphere system are being used to help extend transit times over longer distances.
When all parties involved in the process have a clear understanding of the importance of initial product quality and condition, the use of proper handling and packaging techniques, and the optimization of shipping conditions for the voyage ahead, the results will be “fruitful” all the way to the consumer’s shopping cart.
Eduardo Kerbel is the postharvest technology business manager of Global Container Refrigeration at Carrier Transicold. He 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. Today, he works closely with Carrier Transicold customers, sharing his knowledge and experience to help them advance their success in transporting perishable goods from farm to consumers everywhere.