Members of the CINS Organisation (the Cargo Incident Notification System) have issued guidance and guidelines for the carriage of cocoa butter in freight containers, under the principles set out in the IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units (CTU Code).
Nature of cocoa nutter cargo
Cocoa butter is derived from whole cocoa beans which are fermented, roasted, and then separated. About 54–58% of the residue is cocoa butter, containing 57-64% of saturated fats and 43-36% unsaturated fats. Cocoa butter becomes soft and malleable at 30-32°C and can melt at 37°C. Having become warm or molten, it can retain the latent heat and remain in such a condition down to as low as 17°C.
Upon heating, cocoa butter expands and may cause it to burst the packaging and seep out, staining adjacent cartons and possibly leaking outside of the container or causing damage to the container structure. There have been incidents of cocoa butter melting onboard, resulting in the clogging of ships’ bilges.
Correct selection of freight containers
Cocoa butter is mainly exported from equatorial and tropical countries, so it can be expected that the container will experience long periods of high ambient temperatures. Studies have shown that the air temperature inside the container can be substantially higher than the ambient temperature outside the container. During a sunny day, the temperature can in fact easily reach 20°C above the ambient temperature, i.e. sometimes more than 50°C.
Standard freight containers: Cocoa butter is usually shipped in standard dry freight containers. This is possible where the expected ambient temperatures during the intended transportation are taken into consideration when planning the packaging and the packing of the container.
Reefer containers: Particularly when transporting through hot climate zones, cocoa butter should be shipped in reefer containers to ensure a stable cargo quality throughout the whole transport chain. This cargo may be carried in non-operating reefer containers, since the insulation may provide sufficient reduction in thermal transfer. Long exposure to sun light may however still permit some heat transfer, resulting in the outermost cartons softening. Where it is decided to utilise operating reefers, this will successfully limit the heat transfer to the outermost cartons cargo, so long as an air gap is appropriately maintained around the cargo.
Tank containers: Under special circumstances tank containers are used for cocoa butter. No special precaution is required.
Freight container packing
Cocoa butter should be properly packaged in sealed plastic bags placed into cardboard boxes (cartons). When shipped in dry containers, it is important to make sure that the cartons’ design is suitable to support the entire stacked mass even when the cocoa butter is softened due to elevated temperatures. Stack heights should not exceed the strength characteristics of the bottom-most carton.
The provision of some form of protection to the cargo from radiant heat should be considered if reefers are not used. As noted in section 2.3, reefer containers will provide protection from radiant heat. Where the refrigeration machinery is operating, it is important that the cartons are packed to allow appropriate air circulation.
More rarely, cocoa butter is pumped into a flexitank for carriage. In case this option is chosen it is recommended that COA code of practice for use of Flexitanks is followed in particular where choice of Flexitank and compatibility with commodity is concerned. Such combination is always subject to Carrier acceptance.
Terminal operations: Terminals rarely offer shaded storage for containers. Dry containers carrying this cargo should be packed and transported to the load port terminal as late as practically possible to minimise the exposure time to sun/heat before being loaded onboard. An additional risk to be considered by cargo packers is the time in transhipment hubs where containers are exposed to various weather conditions. The entire routeing of the container should be considered in determining appropriate actions to take in reducing the risks.