In fresh fruit exports, quality is not decided in the orchard alone. The gap between harvest and arrival of the container at the destination port can stretch 10–25 days depending on the market. Throughout that period, temperature is the variable that directly affects freshness, damage rates, and the commercial value of the shipment. Cold chain control is therefore part of the trade specification, not a supporting step.
Post-harvest pre-cooling: an indispensable step
Pre-cooling is the removal of field heat retained in the fruit immediately after harvest. For dragon fruit, mango, durian, or longan, the fruit temperature after picking can be 10–20°C higher than the target storage temperature. If rapid cooling is not applied, respiration and ethylene production continue, causing over-ripening, rapid softening, and reduced tolerance for long-distance transport.
Common methods include forced-air cooling, vacuum cooling for certain types of fruits and vegetables, and cooling with ice or cold water. For tropical fruits exported to South Korea and Japan, forced-air is commonly used because it suits many types of produce and causes less cold shock. Pre-cooling time depends on fruit size, tray stacking density, and equipment capacity, typically ranging from a few hours to less than a day.
One point to note: pre-cooling is only effective when performed as soon as possible after harvest, ideally within a few hours. Fruit that has undergone pre-cooling also needs to be kept in a continuous cold environment; allowing the product to warm up and then cooling it a second time increases moisture condensation, creating conditions for fungal growth.
Refrigerated container: select the appropriate mode and parameters
The reefer container is the primary preservation environment throughout the journey. For fresh produce, two modes are commonly used: cooling and ventilation. Ventilation mode helps remove accumulated ethylene and CO2, but also increases heat exchange with the outside. Conversely, pure cooling mode maintains more stable temperature but requires emission control if the cargo is sensitive to ethylene.
The set-point temperature is not the same for every type of fruit. Dragon fruit is typically shipped at around 4–8°C, mango is usually kept higher to avoid chilling injury, while durian has its own specific requirements for temperature and ventilation. Choosing the wrong set-point can lead to chilling injury or over-ripening. This is a parameter that needs to be confirmed between the exporter, the shipping line, and the importer before loading the cargo.
Besides temperature, relative humidity and airflow speed inside the container also affect weight loss and fruit appearance. Arranging trays at the correct density, leaving space for air circulation, and not blocking the air vents are basic technical requirements but are often overlooked during the loading stage.
Temperature monitoring throughout the journey
Temperature data serves as the technical evidence for the entire shipment. Temperature data loggers are placed inside the container, typically at multiple positions such as the door, the middle, and the end of the airflow, to reflect the actual temperature distribution. Some shipping lines provide remote monitoring data, enabling early detection of incidents such as power loss, open doors, or set-point changes.
In the event of a quality dispute, temperature data serves as the basis for determining the cause: pre-shipment fault, in-transit fault, or post-arrival port fault. Therefore, storing and sharing logger data with import partners should be considered part of the transaction process, especially for markets with high traceability requirements such as Japan and South Korea.
Implications for importers
From a B2B perspective, three questions are commonly raised during negotiations: whether the shipment undergoes pre-cooling, what the set-point and ventilation mode are, and whether temperature data is provided with the shipment. The answers to these three questions directly affect the rate of compliant goods upon arrival at the destination port.
TFIMEX controls the cold chain from harvesting in Tien Giang, Long An, and Binh Thuan through container loading, combining VietGAP/GlobalG.A.P supply sources, VHT treatment when required, and temperature monitoring throughout the journey. Importers who need technical specifications or loading specification sheets for each fruit type can contact export@tfimex.vn.
