Transport and storage of fresh fruit and vegetables in Papua New Guinea

• Department of Primary Industry, Papua New Guinea
• Department of Primary Industry, Papua New Guinea

Papua New Guinea could produce all its fresh vegetable and fruit requirements in its Highlands. However, prospects for developing a viable industry there depend on the ability to move commercial quantities of produce within the country by surface transport, while maintaining it is good condition. Previous attempts to do so have failed badly. During the 18 months of its operation, the Central Highlands Food Marketing Corporation has increased production of vegetables, but inadequate packing and handling have severely limited its success.
The three main aims are to develop improved methods of transporting produce within Papua New Guinea, to determine factors affecting the shelf life of bananas (especially the indigenous Papua New Guinean cultivars) and to develop low-cost methods of extending shelf life.
In a new approach for that country, the transport studies will investigate the use of international shipping containers. Because of the size of particular markets, this necessitates packing the produce in mixed loads, and initial research in Papua New Guinea will seek compromise temperatures for carrying mixtures of chilling-resistant and chilling-susceptible species in refrigerated containers. While this use of containers will minimise mechanical post-harvest damage, other research will investigate curing methods for produce such as sweet and Irish potatoes to reduce microbial damage. Following completion of satisfactory trails with these durable items, the team will attempt to transport more perishable produce such as leafy greens. Static and transport trials will identify the causes of wastage for investigation at the Gosford laboratory, and will progressively test improved curing and fungicide treatments developed at Gosford to control these.
Scientists at Gosford will identify micro-organisms causing this wastage and develop measures such as hot-water of fungicide treatments to control it, particularly for highly regarded Papua New Guinean cultivars that are Irish and sweet potatoes, seeking a single temperature regime to allow curing of both types together. This will include a microscopic study of the effects of curing.
Bananas are a stapic food in Papua New Guinea, and the team there will study the ripening behaviour of major indigenous cultivars. This involves the effect of temperature on the time taken and on the quality of ripe fruit, and that of ethylene in inducing ripening. The team will also investigate how modified atmospheres affect storage of the major local cooking cultivars, particularly in the absence of refrigeration, and the extent of fungal wastage in fruit handled either carefully or in the present rough manner. If careful handling avoids fungal invasion this simple approach will save on the cost of fungicide; if wastage remains important despite it, the organisms responsible will be identified for further studies at Ryde.
A taste panel will be set up to evaluate the effect of ethylene treatment on the eating quality of cooking bananas. Treatments found promising in the laboratory will be tested under semi-commercial conditions.
Scientists at the Division of Food Research will use sealed polyethylene bags to investigate storage of individual bunches with ethylene absorbent and also the possibility of delayed harvesting due to increased carbon dioxide and reduced oxygen within the bag. Studies to determine the maximum period for which bananas can be stored in commercial lots will involve controlled-atmosphere storage and ethylene removal.
Co-operation of various bodies in Papua New Guinea should lead to rapid adoption of the technology.