If there’s one rhetoric in the agriculture and food security sector that’s doing the been doing the rounds on a regular basis, it is that food production needs to grow by 70 per cent in order to feed a world population that is estimated to grow to 9 million by 2050. Adding to this is an extremely high proportion of food-insecure population. The pressure on increasing production of food is so high that a more balanced way to deal with the food security issue is to cut out food losses after harvest. This would turn out to be as effective a strategy in stabilizing the world’s food security problem as growing more food.
Year after year, massive quantities of food are lost due to spoilage and infestations on the journey from farm to consumer. The appalling fact is that in some of the less developed countries with tropical weather and poor infrastructure, the wastage rate is as high as 40- 50 per cent, and unfortunately, on a regular basis. Post-harvest loss is defined as the degradation in both quantity and quality of a food product from harvest to consumption. Here again, there are two kinds of losses – quality losses that affect the nutrient or caloric composition, and quantity loss, which is the loss in the amount of the product. While quality losses are predominant in developed countries, developing countries experience more of quantity loss, which happens when food is lost after harvest to processing, spoilage, insects and rodents.
Agricultural crop loss is a measurable parameter and comprises interconnected activities through the processes of harvest, processing, marketing and food preparation, right until the consumer’s final decision of whether to eat or discard the food. Freshly harvested agricultural produce is a living thing that breathes and undergoes changes during post-harvest handling, and this is the reason it is vulnerable to loss. Again, this ‘loss’ is different from ‘damage’, which means deterioration, and restricts the use of a product, whereas loss makes it impossible to use. Cutting post-harvest losses could, presumably, add a sizable quantity to the global food supply.
Food losses occur due to poor infrastructure and lack of technology, insufficient skills, knowledge and management capacity of supply chain actors, and lack of access to markets. There are internal and external factors contributing to post-harvest losses, for which it’s important to understand the post-harvest system first. The critical point in time is the time of harvest, where the grain needs to be ripe and ‘dry’ to an optimum level. If it retains moisture, then it is susceptible to molds and can rot during storage, and if the grain is too dry, then it is likely to be damaged during threshing. Here, the absence of an established maturity index for some commodities, and low adoption rate by farmers are responsible for the losses.
Apart from the time of harvest, the grower must be aware of the method of harvesting as well as storage mechanisms in order to retain the quality of the product, because poorly designed harvesting tools and rough handling also leads to losses. Also, during processing, excessive hulling or threshing can result in grain losses, making the grain vulnerable to insects.
Storage is also an important component of the post-harvest system. A wide range of storage structures are used throughout the world to successfully store horticultural produce. In general the structure needs to be kept cool, and the produce that is put into the storage must be of high initial quality. Facilities, hygiene and monitoring must all be adequate for effective, long-term storage. In closed structures, control of cleanliness, temperature and humidity is particularly important. It’s also important to manage pests and diseases, since damage caused can result in losses in quality and food value as well as quantity.
After this phase comes the transportation of the produce to the market. In this context, in most developed countries, roads are not adequate for proper transport of horticultural crops. Also, transport vehicles and other modes of transport, especially those suitable for perishable crops, are not widely available. This is true for both local marketing and for export to other countries. Most producers have small holdings and cannot afford to purchase their transport vehicles.
The final phase in the post-harvest system is packaging, which takes place in a packing house or distribution centre. The way it is handled here- like tying up into bundles, also reduces shelf life if not sold quickly. Many of the chemical constintuents naturally present in the food spontaneously react, causing losses of colour, flavor, texture and nutritional value. Also, the longer the time the food is stored, the greater is the deterioration in quality.
Since 2008, there’s been increasing interest in effective intervention for post-harvest losses. In comparison to the benefit it fetches, the investment required to reduce post-harvest losses is relatively moderate and achievable. PHL reduction interventions is increasingly recognized as part of an integrated approach to realizing agriculture’s full potential to meet the world’s increasing food and energy needs.
Technologies and practices to reduce post-harvest losses
There are many examples or improved practices spanning a wide range of technologies from training in better handling and storage hygiene to the use of hermetically sealed bags and household metallic silos. The kind of technology that is finally adopted is based on circumstances such as scale of production, crop type and climatic conditions. Winnowing and cleaning is usually done prior to storage or marketing if the grain is to be sold directly. For majority of the smallholders, this is done manually. A variety of packaging material is also available – natural and synthetic fibre sacks and bags as well as molded plastic boxes seem to be more suitable and have greater promise for packaging roots and tubers and for their transport to distant markets.
Post-harvest technologies can contribute to food security in multiple ways. They can reduce PHL, thereby increasing the amount of food available for consumption by farmers and poor rural and urban consumers and bring about better food security in the agricultural sector. Therefore, reducing PHL clearly complements other efforts to enhance food security through improved farm level productivity. The issue of food losses is of high importance in the efforts to combat hunger, raise income and improve food security in the world’s poorest countries.