The banana is one of the most important perishable commodities in international trade. Cargoes of bananas are carried either in the holds of reefer (refrigerated) vessels or refrigerated shipping containers. A voyage may take a few days or several weeks from the loading to the discharging port. In the past decade, the banana trade is fast-moving to almost full containerization. The international banana trade is based on the harvesting and transportation of hard, green, unripe fruit, which is later ripened in the country of consumption. The lowest temperature at which bananas may safely be shipped is in the region of 13.3°C, which is optimal for extending postharvest life. At temperatures below this critical value, there is a risk of chilling injury. In contrast to most other fruit commodities, bananas are usually presented to the carrier at ambient temperature. It is the task of the ship or container to cool them safely to the carriage.
Technological changes have allowed for the development and growth of the international banana trade. One of the major developments of banana handling techniques was the packing of bananas in cardboard boxes. The mechanization of handling techniques in loading and discharging areas, through cranes in ports and the use of forklifts or even robots, are also very positive advances for the movement of such a delicate fruit as bananas. Advances in refrigerating technologies are very important for the development of banana reefer transport and allow for bananas to reach faster and with better quality the consuming centers.
The new methods for transporting perishable technologies better control the cold chain and allow for tracing the process through computerized systems. When transported by sea, bananas are said to be ‘put to sleep’, reducing the amount of oxygen in the storage area to extend their shipping life. Some of the technologies used are controlled atmosphere, controlled humidity, remote access monitoring, enhanced airflow, better insulation materials and techniques, and internal monitoring controls.
The banana supply chain is as follows:
- The banana producers can be small independent growers, national companies, or multinational companies. From the production sites (mostly located near plantations in South-Central America), the boxes of bananas are transferred to the loading port. In the chosen port, the boxes are consolidated into pallets loaded directly inside a bulk ship or in reefer containers.
- Bananas are transported by sea through independent reefer carriers (specialized or containerized) or by reefer fleets owned by the same multinationals.
- After their unloading in the importing countries, bananas may move through importers before their arrival to retail outlets to be sold to consumers. At the port of destination, the vessel is unloaded and hauled towards the retailers’ infrastructures (reefer warehouses and platforms). Before the ship’s arrival, a barcode manifest of the cargo is sent to the terminal so that it is known beforehand what the volume of the products are and the type of packaging (boxes, pallets, containers). This manifest is sent electronically to the terminal and automatically uploaded into the IT system of the terminal.
The equipment typically used in the discharge process are quayside cranes, forklifts, and pallet jacks. Some of the vessels that arrive at the terminal do have their own onboard cranes, but quayside cranes are faster and more efficient than the on-board cranes:
- When reefer containers are transported by a mainline container vessel, the reefer container usually ends up at a full container terminal in the port. It is then brought to the banana facility by truck or barge (if available).
- Reefer vessels usually also have reefer containers on deck. These reefer vessels call at the banana terminal directly, where they first unload the reefer containers before engaging in below-deck cargo handling operations of palletized banana boxes.
The equipment used to discharge bananas depends on the unit load used:
- Discharge of reefer containers: Reefer containers are handled by mobile shore cranes or, when availably, by STS container cranes. Reefer containers are plugged in at the electrical outlets that are provided at the terminal, and their cargo is stripped later on in a warehouse adjacent to the quay. The pallets inside the containers are transferred to the warehouse with forklifts and are processed in the same way as the rest of the pallets.
- Discharge of pallets: In order to begin the discharging process of the pallets from the hull of the reefer vessel, the first batch of four pallets should be unloaded. That will happen with the use of a sling. These four pallets have been prepared from the port of origin and are bound together with belts. That applies to each level of the hull because this way there a square opens in the hatch, and then the forklifts inside the vessel are able to handle the rest of the pallets. These first pallets will be picked up by a sling and then forklifts that are waiting in quayside will collect them and transfer them to the warehouse where the temperature is controlled. Once this is done, inside the vessel with pallet jacks and forklifts, the pallets are placed in a pallet cage or pallet tray where up to 8 pallets can be accommodated depending on the equipment. The pallets are offloaded in the quayside, and again forklifts which are waiting on the quayside, collect them and move them inside the warehouse. Consequently, the pallets are exposed to the open air for a limited amount of time and only for transportation from the quayside to the warehouse. A number of reefer vessels have side doors and the loading and discharging is done via the ships’ side-door and cargo elevators. But these operations are not as productive as using the terminal’s cranes.
- Discharge of loose boxes: In the past, it was possible for loose boxes to be found in the hull of the ship. In order to unload loose boxes, spiral unloaders were used that can reach any required point in the ship’s hold to take in the boxes. In the hull, the boxes were manhandled onto the telescopic belt and traveled automatically into the spiral. As soon as the loose boxes were discharged, they were guided to the warehouse using a conveyor belt. Palletizing robots were used for palletizing the boxes before bringing these to the cold store.
With the introduction of pallet cages and containerization, the number of banana boxes handled per minute per crane increased from 50 when using a spiral unloader to 385 for the pallet cage and 480 when pallets are containerized.
As soon as the pallets are offloaded from the vessel, they are transferred to the warehouse. Depending on the type of warehouse (automated or not), different processes apply:
- Automated warehouse: this type of facility uses automated storage and retrieval system (AS/RS), then the pallets enter the reception area of the warehouse and are placed on the conveyor belt with a forklift. As the pallets move along the conveyor belt, they pass a scanning device that scans the barcode that is affixed to the carton. In this way, the warehouse management system of the terminal is updated. Each pallet follows a pre-designed path to the actual stacking area, and they are stored according to temperature.
- Traditional warehouse: block stacking is typically used, and the pallets are stacked at the aisles by temperature and depending on how they need to be delivered (by vessel, container, etc.).
When the receiver/buyer requests his cargo, then his pallets are collected from the warehouse and moved to the shipping area and are loaded to the dedicated truck. In this process, the truck is parked against a docking space of the warehouse. The pallets are loaded onto trucks using forklifts. In this process, there is little exposure to non-controlled air. The trucks are refrigerated trailer trucks.