Transport practices for avocado

Transport of avocado generally takes place in (refrigerated) trucks, reefer containers, or by plane. Checks and proper loading are always important to maintain good (temperature) conditions for the product during transport. Refrigerated transport is often necessary. Trucks and reefers can maintain a low temperature, but do not have enough cooling capacity to lower the product temperature. Therefore, products must be pre-cooled before entering the refrigerated truck or reefer. During transport and waiting periods, the load must be well covered to protect against dust, sun and rain. Careful driving and handling are essential to prevent damage to produce from mechanical actions.

Loading truck in avocado orchard. Photo by WFBR.

Proper transport conditions for avocados

The pick-up of avocados from the orchard should follow soon after harvest because it is essential that avocados, especially for overseas shipment, are cooled as soon as possible. Therefore, delays between harvest and cooling should be avoided. After cooling in packhouse, they can be transported further in refrigerated trucks or reefer containers. The best transport temperature for avocado depends on variety, production areas and the season, it is usually in the range between 5 and 7 ºC. The optimum humidity would be around 90% RH. The temperature during transport should be kept constant to reduce condensation. Higher humidity or condensation may encourage the growth of moulds.

Attention points when transporting avocados

  1. Loading at avocado farm. Photo by anarociogf/Shutterstock.com

    Loading at the farm

    Upon pick-up, the crates or other packaging must be stacked carefully and tightened to ensure they do not shift or fall-over during transport. In the case of larger trucks and loads that do not fully occupy the truck floor, the tightening must be done by placing (pallet-)edge protectors at the edges of a batch of stacked field crates. Especially for warm loads (picked up at harvest), air ventilation through the stacks should be warranted
  2. Loading avocados after packing and precooling. Photo by WFBR.

    Loading after pre-cooling

    The loading must be realized preferably from a climate-controlled loading dock via “cold tunnels” (<8°C) into the truck or reefer. This prevents ambient air from entering the pre-cooled reefer container, or truck, or the climate-controlled loading dock. Apart from maintaining the avocados at the desired low temperature, this is important in order to avoid condensation, which will occur when warm moisture-laden air enters the reefer container or truck
  3. Stacking of precooled boxes as a solid block in a refrigerated truck and reefer. Photo by WFBR.

    Stacking of refrigerated truck and reefer

    In reefer containers, with bottom-air delivery system the cargo must be stacked as a solid block with only little space between the cartons and the reefer container wall to avoid short–cycle airflow. Also do not stow above the red line at the reefer wall. Pay also attention to the coverage of the open floor and forklift pocket openings pallets in the rear.
  4. A reefer container. Photo by WFBR.

    Settings of reefer containers

    Temperature may be set between 5 and 7°C. For specific production areas and chilling sensitive avocado fruits, a stepdown temperature program may be applied. When transport under regular atmosphere, set up the ventilation (fresh air) panel to 120m³/h for a 40 foot container to remove CO2 produced by respiration of avocado. When avocado are transported under Control Atmosphere, oxygen level should be set up between 2 and 5%; 3 and 10% for CO2 levels
  5. Image of a plane circling the earth by Creative icon styles/Shutterstock.com

    Air transport

    The volumes of avocados which are transported by air is small. For transit at the airport, foil laminated thermal blankets can be used to cover a whole pallet if cold chain temperature cannot be guaranteed
  6. Temperature mangement in the packhouse. Photo by Sorn340 Studio Images/Shutterstock.com

    Temperature logging

    The cold chain should not be broken with optimal temperature range depending on variety and maturity. Lower or higher temperatures can easily result in loss of quality. Cooled avocados that are re-warmed when the cold chain is broken, can have condensation on the fruit. This will increase their susceptibility to fungal decay. Good quality control during transport includes temperature logging
  7. Unloading at import destination. Photo by WFBR.

    Unloading

    Before unloading the container, ventilate the container to bring back atmospheric oxygen level inside. Unload carefully to avoid handling damage. The pallets (or other packaging) with avocados must be moved directly to a cold storage. When pallets are moved to the cold storage upon unloading, it is recommended to sample fruits for inspection before stowing the pallets in the cold storage. Visual appearance of avocados, but also of packaging and pallets can be documented via photographs.

"A reefer container or truck is only capable of maintaining the produce temperature, not to lower it. Therefore, products need to be pre-cooled."
Eelke Westra - Specialist Postharvest Technology