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Post harvest loss: management
and environmental conditions
By Nisar Ali Shah and Dr. Umar Farooq

Balochistan has the largest area under fruits in Pakistan as nearly one million tons of fruits are annually produced from 0.239 million hectares. In this way, Balochistan's share in country's fruit area and production is 32.6 per cent and 17.4 per cent, respectively. The production of deciduous fruits (particularly apple) in Balochistan has a special significance among other fruit growing areas. This is because the environmental conditions are relative far more suitable for the production of apple. Therefore, apple is the first largest planted fruit in Balochistan and it is second most produced fruit after dates in the province. Apple is grown in highlands of Balochistan and it covers 0.101 million hectares with a production of 0.224 million tones having retail value of about Rs6.7 billion. The Tur-Kulu (Red Delicious) and Shin-Kulu (Golden Delicious) are the famous varieties for their very attractive color and taste throughout Pakistan. Therefore, these varieties fetch relatively high prices in the markets of Sindh, Punjab and NWFP. In Balochistan, the share of apple is 42 per cent in the total area under fruits and 23 per cent in terms of total fruit production. Pishin with Killa Abdullah, Mastung and Zhob are the main apple producing districts. A recent farm level apple varietal survey in Pishin and Killa Saifullah districts revealed that Tur Kulu and Shin Kulu and Kaja are major varieties occupying >50 per cent, 25 per cent and 10 per cent of total apple orchard area, respectively. These estimates have some meanings when considered from post harvest loss management point of view.

For year round availability of this fruit, apple must be stored at 32oF and relative humidity of 90 per cent. Considering the geographical spread of Pakistan, marketing of this fruit in the country (i.e. all the three provinces and AJK) vis-‡-vis storage requirements to maintain the quality of fruit till it reaches the consumers, careful handling of this fruit at all stages is very important. This will control seasonal price fluctuations and ensure availability of good quality fruit to the consumers for a relatively long duration at affordable prices because the losses during the transportation are ultimately transferred to the consumers in the form of poor quality and high prices. Moreover, unduly high prices also result in reducing the demand which leaves less incentive for the producers to increase production because the benefits of high prices are also not passed on to the farmers as the commodity has already left the farm gate.

Balochistan has the poorest communication system and infrastructure development. It is poorly endowed with road infrastructure, marketing and appropriate storage facilities. This has resulted in higher post harvest and transportation losses. Generally speaking the longer the distance and time are involved from the production to the consumption of horticultural commodities, more opportunity there is for loss of all kind to occur. A substantial quantity of production is subjected to post-harvest losses at various stages of marketing. The quantum of loss is influenced by several factors like method of harvesting, packing and transportation etc. During distribution and marketing, significant losses are incurred which range from a slight to total spoilage. Postharvest losses may occur at any point in the marketing process, from the initial harvest through assembly and distribution to the consumer.

The causes of losses are many. The primary causes are: biological and microbial (i.e. pests and diseases); chemical and biochemical (i.e. contamination with pesticides and other chemicals, toxins and bad-flavour due to diseases); injuries, cuts, bruises, abrasions, peeling and trimming etc; environmental (i.e. overheating, chilling, freezing, dehydration etc.), and physiological (i.e. sprouting, rooting, transpiration etc.). The secondary causes include inadequate curing, improper storage, inappropriate transportation, inadequate production and harvest planning etc. He also indicated stages like at harvesting, product preparation, preservation, processing storage and transportation etc. Various studies reveal that about 15 per cent of apple is lost due to various reasons from its production point till it reaches the consumer.

Respiration is a good indicator of the metabolic activity of fruit tissues and can serve as a commercial indicator of the potential storage life of the produce. Flavour is one of the most important aspects of quality which develops under normal conditions. Some horticultural products are conditioned by exposing them to certain temperatures and conditions. Post harvest deterioration of fresh horticultural produce is due to water loss, senescence, and development of physiological disorders and fungal attack. While refrigeration is the principal means of retarding this deterioration, and external atmosphere control is finding wider application, certain ancillary treatments are of high value. Waxing of the fruit surface adds shine and reduces water loss and rate of transpiration, thus improving external appearance and extending storage life. Several wax formulations have been developed and tested.

Post-harvest technology of horticultural perishables is comparatively a new field in the agriculture sector of Pakistan. Its economic and nutritional importance cannot be ignored as depending upon commodity more or less 30 per cent of the produce is wasted during its transport from farm-gate to consumer. Horticultural crops are relatively more valuable in terms of price than the field crops. Therefore, these losses cost to the nation in billions of rupees which, could be avoided and can result in increasing the availability of horticultural commodities by adopting appropriate post-harvest technologies. Investment in development and transfer of post-harvest technologies is of particular importance for Balochistan where filed crops production sector is dismal as compared to other provinces of the country. Apart from creating awareness, there is a need to impart training to the stakeholders for improved operations for harvesting, post-harvest handling in the orchard, post-harvest treatments, grading, packing, storage, transport and marketing etc. A good amount of research and development work has been carried out in the horticultural advanced countries in this regard. No doubt, the concerted efforts should be made for transfer of technology, but it will also require trained manpower in this specialized field as well as creating viable receiving-end by continuous awareness campaigns as a national cause.