Pakistan have a very fertile and variety of soil. It has variation in its soil and climatic conditions, which is very favourable for the production of fruits, vegetables, flowers and other crops. Mostly high valued fruits, vegetables and crops are produced in our country. Pakistan, ranging from tropical to temperate, allows growing 40 different kinds of vegetables and 21 types of fruits. Major vegetables grown include potato, onion, chilli, melons, cucumber, tomato, turnip, okra and pea, whereas, citrus, dates, mango, guavas, apple, banana, apricot, grapes, almonds, peach, plum and pomegranate are the main fruit crops.
At present area under fruits and vegetables is 0.995 million ha (4.3 per cent of the total cropped area) with the total production of 10.992 million tons. Area and production both increased in the past but at a very low pace. The major factor limiting increase in area and production remained high investment and low return to the grower. Post-harvest losses in fruits and vegetables range from 25 to 40 per cent or even greater. Consumers prices rise in addition to hidden quality losses. These losses bring low return to growers, processors and traders and country suffers in terms of foreign exchange earnings. Primary factors of post-harvest losses in citrus are mechanical, physiological, pathological or environmental factors are directly responsible. Mechanical loss is caused by careless handling during harvesting, packing, transportation, storage etc. Some insects and birds are also responsible for the mechanical injury.
A significant portion of losses during the post-harvest period is attributed to the diseases caused by fungi and bacteria. Besides attacking fresh fruits and vegetables, these organisms also cause damage to canned and processed products. Environmental factors, temperature, humidity, composition and proportion of gases in controlled atmospheric storage also play an important role. High temperature and relative humidity favours the growth of micro-organisms which cause extensive damage to the produce. In fruits and vegetables, the quality of produce starts deteriorating right after their harvest. Post-harvest produce losses are poor pre-harvest measures-adoption of poor production techniques (varieties with low shelf life, imbalance use of nutrients, insect pest and disease infestation and a biotic stresses; low tech harvesting procedures-non-application of pre-harvest recommended treatments/practices, harvesting at improper stage and improper and improper care at harvest; and post-harvest problems-non-removal of field heat, dumping produce, moisture condensation causing pathogen infestation, packaging in bulk without sorting and grading of produce, improper transportation and storage, and distant and time consuming market distribution.
In order to preserve the produce quality different post-harvest techniques are recommended for variety of produce. These techniques include; hyper cooling, refrigeration and freezing, modified atmosphere packaging, modified packaging storage, control atmosphere storage, skin coating, hypo-baric or low pressure storage, irradiation, dehydration, canning, high pressure processing and pulsed electric fields and pulsed light applications. Transportation and distribution of the fruits and vegetables are the most important areas of post-harvest losses. In Pakistan, the transportation of perishable commodities is in the most precarious stage. For local market, the produce is brought either by bullock cart or tractor trollies and injuries done to the product.
Quick transport done in order to maintain the quality with minimum damage during transportation is very important for successful marketing of the produce. It is very important that horticultural produce reaches the market as soon as it is possible and at a time when the market needs it the most. Storage also play important role its main objective is to extend the storage life of fruits and vegetables and increase their period of availability.
In order to promote horticultural industry, standardization of pre-harvest and post-harvest management technologies minimizing post-harvest losses and to enhance foreign exchange earning to the maximum extent is therefore essentially required for necessary adoption. Efforts are being made both at federal and provincial level to minimize these losses to safe guard the interest of growers, processors, traders, retailers and consumers.
The writers are associated with the Institute of Horticultural Sciences, University of Agricultural Faisalabad and Post-harvest Research Centre, Ayub Agricultural Research Institute Faisalabad