Both quantitative and qualitative losses occur in horticultural crops between harvest and consumption. Fresh fruits and vegetables accounted for nearly 20% of consumer and foodservice losses, which are due to product deterioration, excess perishable products that are discarded, and plate waste. In developing countries, the losses are expected to be around 30% of the total produce every year.
Factors affecting food losses-
There are biological as well as socio-economical factors affecting these losses. The biological factors can be reduced by addressing the socio-economic factors like better handling, storage infrastructure, cold chain transportation etc, but it requires the administration’s attention and better policies to reduce the losses.
As an example, the following table gives estimates of the quantitative losses of rice for each stage in the the post-harvest system in Southeast Asia.
| STAGE | LOSSES |
| Harvest | 1-3% |
| Handling | 2-7% |
| Threshing | 2-6% |
| Drying | 1-5% |
| Storage | 2-6 % |
| Transport | 2-10% |
| Total | 10-37% |
Source- http://www.fao.org/3/t0522e/T0522E04.htm
BIOLOGICAL AND ENVIRONMENTAL CAUSES OF LOSSES
Biological losses include deterioration due to respiration rate, ethylene production, compositional changes leading to the deterioration of colour, texture, flavour, and nutritive value, mechanical injuries during handling, water stress, etc. Other losses include sprouting, rooting and physiological disorders during growth making them unappealing to the consumers.
These major biological losses depend on environmental factors like temperature, humidity, exposure to oxygen, CO2 and ethylene and sanitation during storage. Loss of weight occurs mostly due to moisture loss which can reduce the weight of the product over a period of time, leading to lower-income to the farmers for their harvest.
SOCIOECONOMIC FACTORS
Inadequate marketing system
Farmers can produce large quantities of good-quality fruits, grains and vegetables, but, if they do not have a dependable and fast means of getting such commodities to the consumer, losses will be extensive mostly due to biological losses mentioned earlier.
Lack of required machines and tools and expensive machinery
In developing countries the majority of the farmers are small scale farmers and the high tech machinery are just not viable for the amount they harvest. Moreover, the machines used in harvesting and post-harvesting are very expensive and small scale farmers cannot afford them. There are measures taken by people in this regard where cooperatives buy the machines and rent them to the farmers during harvest seasons, but the maintenance of these machines are expensive as well.
Poor storage infrastructure and transportation
The developing countries are facing challenges of constructing advanced storage solutions using Controlled atmosphere technology in order to store the harvest especially perishable fruits and vegetables. This is due to the extensive cost of these type of stores and lack of knowledge among the farmers who still prefer the traditional storage methods even though they lead losses as much as 30% in a short period of time.
Transportation in a developing country like India creates a major issues, especially for fruits and vegetables as a commodity like apples has to be transported from Himachal Pradesh, Uttarakhand to metros in the south like Chennai and Bangalore. These fruits have to cover thousands of kilometers and due to lack of cold supply chain in India (mostly because of the cost and economics of transportation) these perishable fruits like many others face a lot of biological as well as physiological losses.
Lack of information and education
Another factor influencing the post-harvest losses is a lack of education of farmers who generally have a herd mentality. New technology and better scientific methods are very hard to explain to this crowd especially in the rural areas of the developing countries.
STRATEGIES FOR REDUCING POSTHARVEST LOSSES
There are many strategies and technologies available which are being used to reduce the food loss at each stage in the supply chain. But, there are still gaps to be filled and following the guidelines for better practices can significantly reduce the losses.
| TABLE 1: STRATEGIES FOR REDUCING POSTHARVEST LOSSES FOR GRAINS AND CEREALS | |
| Harvesting | The crops should not be harvested too early as it incurs a loss in nutritional and economic value. Quality can only be maintained if the harvest is done at the proper maturity stage and at peak quality. |
| Drying | Grains should be dried in such a manner that damage to the grain is minimized and moisture levels are lower to oppose mold growth during storage (usually below 13-15% ). The harvested crop may be dried in the yard or in a crib. |
| Threshing | For some grains, like millet threshing, may be delayed for several months after harvest stored in open cribs. Some other small scale machines can be used for like maize sheller or Rice mechanical threshers. s |
| Winnowing | There is little incentive for smallholders to provide well-cleaned grain for marketing; as a result profits from sales are limited. |
| Storage | Storage plays a key role in reducing losses, therefore they should be constructed in such a way as to provide dry, well- vented conditions allowing further drying in during storage, provide protection from rain and groundwater; and are sealed to protect the crop from rodents and birds and temperature fluctuations. |
| TABLE 2: STRATEGIES FOR REDUCING POSTHARVEST LOSSES FOR FRUITS AND VEGETABLES | |
| Harvesting | Pre-mature and improper harvesting may lead to early infestation with molds and viruses leading to rotting. If harvesting operations are correctly undertaken there is greater scope to improve shelf life. Proper tools and equipment along with trained workers for harvesting should be a priority prevention of food loss. |
| Handling | Breaking of the skin also stimulates physiological deterioration and dehydration. Careful handling significantly reduces post-harvest losses. |
| Sorting and cleaning | Sorting/ grading along with appropriate packaging and storage will extend shelf life, maintain wholesomeness, freshness, and quality of the fruits and vegetables. |
| Packaging | Using ventilated containers for packaging is a very important factor in cutting down losses in these crops during harvesting, transportation, marketing, and storage as ventilation doesn’t allow the foul smell to settle in the packaged items. |
| Storage | Shelf life can be extended by maintaining a commodity at its optimal temperature, relative humidity and environmental conditions like in CA chambers. It’s a must to store only high-quality produce only as the damaged ones can rot all the stored items. |
Effect of food losses to food security and environmental sustainability
Food security means when all people, at all times, have physical and economic access to sufficient safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life. These four components are a must in order to attain food security-
· Physical availability of food
· The economic and physical access to food,
· Food utilization
· Stability of each of these three over time
Now, the food that we produce today, suffers approx. 30% loss avg every year. And with the earth population estimated to reach 9 billion by 2050, the requirement for food is only going to increase. Therefore, the need for the more cultivated areas will increase, which is not possible. Therefore, measures need to be taken now to increase the productivity of the land in order to feed the increasing population. But, increasing productivity is not easy as it increases the stress on the land, environment and ecological system as a whole. Right now, almost 70% of the total consumed freshwater is being used for agriculture and in order to increase land productivity, more water will be required. The water footprint of the agriculture sector is the highest and if we calculate the water footprint of the food loss per year, then it surpasses the water footprint of the USA and China. Now, we know that most of the high population areas are facing scarcity of water, be it metros in India, the USA, China or any other place. Therefore, the need is to reduce the postharvest losses mentioned earlier in order to attain food security.
In India, agriculture is still primitive due to a lot of socio-economic reasons like large families of farmers has led to a very small land bank for next-generation farmers. A high percentage of farmers in India today are small scale farmers. This has led to a lot of economic issues in the agriculture sector. This, in turn, has kept agriculture on a primitive level as new technologies are not viable on these small scale farmlands. These small farmer’s earnings have taken a hit as well and therefore they do not have access to good storage infrastructure. Due to the low income, they are unable to purchase the right tools and types of machinery required for harvesting, drying of grains, cutting of roots, fruits, and vegetables, storage and transportation. This leads to poor quality products at a very early stage of the supply chain and hence they don’t fetch good prices in the market and the whole cycle keeps repeating.
Similarly, due to the lack of knowledge and storage infrastructure support, the farmers are forced to sell their products just after harvest, leading to surplus supply and lower prices in the market. The proper method of storing the harvested crops is in cold storages but they are expensive to build and although government subsidies are available, it is very hard for a farmer to develop such a storage unit on is own. Therefore, the farmers tend to store their harvest in a traditional manner, leaving their produce susceptible to pest, rodents, moisture, and any other environmental factors.
Transportation has been figured out as a key component in the supply chain and in food loss. Nearly 7-10% of grains are destroyed during transportation due to lack of good handling techniques, poor transportation methods and poor harvesting methods lead to rodent attacks while on the road.
These issues have a direct impact on the environment as well.
There is not enough available water for human resources and to meet the demands for the growing economics. And that about the irrigation industry and domestic uses all including that water table, the groundwater table is depleting in every country. For eg., A cup of coffee takes up about 208 liters of water to make if one includes all the elements involved in the process. Similarly, there are many other crops with very high water footprints like rice, avocados, etc. And due to poor irrigation methods and lack of knowledge among farmers, the wastage of water has been a matter of concern. Moreover, the water footprint of each crop increases as it moves up the supply chain, and if the harvested crops are damages and lost then that amount of water is also wasted. This is a great concern in developed countries wherein plate wastage is very high, which leads to a high water footprint on the crops.
Water is the key to life and at this rate, all the urban areas where a high amount of population resides will face a shortage of water. Therefore, in order to increase environmental sustainability, measures need to be taken by the government and policymakers to improve the irrigation systems, develop an education structure for the farmers to teach them about the implications of their actions. Better storage facilities, cold storages should be developed and maintained by the governments in the rural areas where farmers can store their produce on a rental basis. This will reduce a lot of postharvest losses and also reduce the stresses on the cultivated land.
-SURBHIT GODHA, 5 APRIL, 2020
References-
1. https://www.actahort.org/members/showpdf?booknrarnr=682_296
2. http://www.fao.org/3/t0522e/T0522E04.htm
3. https://www.actioncontrelafaim.org/wp-content/uploads/2018/01/technical_paper_phl__.pdf
4. POST-HARVEST LOSSES AND STRATEGIES TO REDUCE THEM, Victor Kiaya, 2014, pg.1-25. URL- https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/postharvest-losses.
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