Reducing Post Harvest Loss in Wheat for Food Security

Supplying the food requirement of a fast-growing global population is posing a big challenge to humanity. The population is predicted to reach 9.1 billion by 2050, necessitating an additional 70% of food production. Most of this population growth is likely to be attributed to developing countries, many of which are currently dealing with hunger and food insecurity.

Crops provide around 93% of the food used to feed the world's population, with cereals accounting for two-thirds of that total (wheat, maize, barley, sorghum, and millet). These cereals provide most of the calories and protein. Wheat, maize, and rice account for over 80% of global cereal production. Wheat is the most abundant cereal. Wheat is grown in 27 developing-world nations. After the Russian Federation, China, the United States, India, Canada, Australia, and Turkey, Pakistan is the eighth greatest producer.

Wheat is the most significant crop and the staple diet for most of Pakistan's people. It also meets the nutritional needs of those who cannot afford high-protein meals such as meat and legumes. Wheat, as a staple dietary grain, provides 72 percent of the calories and protein in the regular diet. Pakistan has the largest per capita consumption of wheat flour in the world, at 124 kg per capita. It is exceeded from China and India, while both having a higher level of GDP and population than Pakistan.

Growing urbanization, climate change, and land use for non-food crop production enhance the concerns about food security. To meet rising food demand, most governments have concentrated their policy during the previous few decades on enhancing agricultural production, land usage, and population management. Unfortunately, Post Harvest Loss (PHL), a major issue, does not receive the attention it deserves, with very limited research resources dedicated to it in past years. According to a research study conducted by FAO, around one-third of the food produced (about 1.3 billion tons), worth around US $1 trillion, is lost during postharvest processes around the world.

Post harvest loss refers to food loss that occurs throughout the food supply chain, from crop harvesting to consumption. The extent of post-harvest losses in the food supply chain varies substantially across crops and regions. Yet, a substantial amount of produce is wasted during post-harvest activities due to a lack of expertise, insufficient technology, and/or inadequate storage facilities.

Poor post-harvest practices account for 10% to 15% of wheat losses in Pakistan. Throughout the crop transition from field to consumer, it must undergo many activities such as harvesting, threshing, cleaning, drying, storage, processing and transportation. During this journey, crops are lost due to numerous factors such as inappropriate handling, inefficient processing facilities, biodegradation due to microbes and insects, etc. It is critical to understand the supply chain and identify factors that cause food losses at various stages.

Harvesting

Harvesting is the initial step in the wheat supply chain and is a vital operation in determining crop quality. Harvesting timing and method (mechanized vs. manually) are two major elements affecting harvesting losses. If harvesting activities are not carried out at the appropriate crop maturity and moisture content, significant losses occur. Too early wheat harvesting at high moisture content increases drying costs, makes them susceptible to mold growth and insect infestation, and results in a high volume of broken grains and low milling yields. Moreover, keeping the mature wheat crop unharvested leads in substantial shattering losses, exposure to bird and rodent assault, and losses due to natural calamities (rain, hailstorms etc.). Harvesting is critical because the crop must be harvested as soon as possible to make space for another crop. Harvesting period may also coincide with heavy rain, severe cyclones, and floods. Given these circumstances, appropriate technology is required to reduce harvesting time.

Wheat is harvested in Pakistan during the hot and dry summer months of March to May. Farmers are aware that the harvested wheat must be dry enough for threshing and storing. It is uncommon to use artificial drying. The manually picked wheat crop is wrapped into small bundles and placed in bunches of 10 - 15 bundles before being left in the field to dry for one to three days. Combine or mechanical harvesters produce a higher proportion of immature grains and offer a moisture threat by not allowing the grain to dry.

Threshing

In Pakistan, threshing is mostly mechanical. Tractor-driven threshers and, on occasion, combine harvesters are utilized. The design and maintenance of the thresher are critical to lowering the broken grain percentage. Delays in threshing following crop harvesting result in significant quantity and quality loss because the crop is exposed to the atmosphere and vulnerable to rodent, bird, and insect assault. As with harvesting, a shortage of machinery is a main element of this delay, which results in large losses. Excessive moisture accumulations in the crop lying in the field may potentially result in the initiation of mold growth in the field.

Transport

In developed countries, very efficient bulk handling techniques exist to load loose wheat into vehicles. Wheat is moved to the grain-processing center in a single trip using an auger, dropped into a receiving bin, and then carried by a mechanical conveyor through the cleaning and drying operations and into storage. Then, it is transferred out of storage into the flour mill at the same facility, where the completed flour is mechanically bagged, put into trucks by elevator, and taken to a commercial bakery or retail market without once being handled manually. Government policy addressing the optimum degree of mechanical wheat handling is frequently focused on the desire to maximize unskilled labor employment.

In Pakistan post-harvest handling, transport and storage of grains at the farm level is done partially in bulk. Wheat is typically conveyed in animal-drawn carts or on camelback. Tractor-driven trolleys and trucks are used by large farmers. Bags are used for transportation in each case. When old torn bags are utilized, they spill grain and cause loss. Often, 100-kg bags are used, which are difficult to transport. Bags are also at risk from hooks that shred them, the rough surface of carts and trolleys, and nails that harm sacks as they are dragged. Transportation happens between farms and markets, between markets and consumers, between markets and temporary storage, between temporary storage and long-term storage, and between long term storage and consumers. Poor quality Jute bags are used extensively during transit and even storage, which results in significant spillage rates due to leakage from the sacks. High quantities (typically 100 kg of grains) in each bag, as well as hooks used to lift these bags, cause tears and significant spillage.

The food grain trade depends upon labor. Therefore, handling, transport and storage of marketed grains in bags is common. Availability of cheaper jute bags also encourages handling, storage and marketing of grain in bags. Large quantities of food grain must be moved through road transport, another major factor promoting use of bags.

Storage

The greatest amount of loss happens during wheat storage due to a lack of adequate storage facilities. The estimated storage requirements are three times greater than the current storage facilities available in Pakistan.

Wheat delivered from the farm to the local market, or a government food department involves a variety of obstacles. Because mills must be able to store enough grain for 30 to 60 days of milling, this wheat may be stored in sheds, massive steel bins, concrete silos, or flour mill holding bins. Wheat can be temporarily stored on railway cars or open stacks in market towns, where the protection is no greater than on a village threshing floor.

In Pakistan, the involvement of millers in wheat storage has been constrained by government subsidies to public sector institutions, which acquire major portion of the wheat harvested. Rather than buying wheat themselves, millers discovered that it was less expensive to procure from these government agencies, who handled most of the long-term storage.

Storage losses are divided into two types: direct losses caused by physical loss of wheat grain and indirect losses caused by quality and nutrition loss. It is critical to include both insect damage and losses during storage, rather than merely weight loss. "Damage" can refer to visible signs of deterioration, such as holes in the grains. It mostly impacts grain quality. The decline in quality results in value loss of the goods, and sometimes leads to total rejection as well. Spillage from leaky sacks causes some loss, which can be noticed when the store is emptied, and the spilt grain remains on the floor.

Insects, molds, birds, and rodents are the main culprits impacting wheat loss during storage. Temperature, humidity, and the type of storage all have an impact on the environmental conditions in storage. High temperatures deteriorate, whilst low temperatures are ideal for storage. High temperatures hasten grain respiration, which creates carbon dioxide, heat, and water, all of which promote deterioration. Grain storage is also affected by humidity. Increased humidity promotes deterioration, and decreased humidity promotes storage.

Conclusion

Post harvest loss is a complex issue with varying scales depending on farming practices, climate conditions, and country economy. Storage losses account for the largest share of all post-harvest losses in developing countries, threatening farmers' livelihoods. Most harvested grains are held in traditional storage infrastructures, which are insufficient to prevent insect infestation and mold growth during storage, resulting in significant losses. Although a significant concern, storage losses can be reduced by using efficient storage technologies, improving infrastructure, and changing storage behaviors.

It is impossible to deny that reducing wheat post-harvest losses throughout the supply chain is the most critical aspect of ensuring food security. Reduced losses will ultimately expand food production prospects, aid in poverty alleviation, improve rural development and improve farmers' Livelihood in developing countries.

Please note that the views expressed in this article are of the author and do not necessarily reflect the views or policies of any organization.

Aslam Memon is Director at PARC-SSRI, Tandojam and Muhammad Ismail Kumbhar is Professor at Sindh Agriculture University Tandojam, Pakistan

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