Innovative Techniques to Contain Storage Loss of Food-grains

India is to produce 251.12 MT of food-grains in 2014-15 (estimated to have declined by 5.25 percent due to poor monsoon and unseasonal rain in the past two months). The major components of production are 90.78 million MT of wheat, 102.54 million MT of rice, and 17.38 million MT of pulses. With the pace of extensive research and development (R&D) in the field of crop science, introduction of high yield varieties and application of modern technologies, the increase in production of food-grain is poised to increase manifolds in the coming years. So far, extension agencies have concentrated on increasing production. The time has now come to see that grain saved is equivalent to grain produced. High technology has led to production targets being achieved, but much less attention has been given to minimising losses, which have remained constant since the beginning of the ‘Green Revolution’. Annual post-production losses by crop in India, expressed as a percentage of total production, are: wheat eight percent; paddy 11 percent; pulses 9.5 percent; and all food-grains 9.3 percent. With the above percentage losses, India is likely to lose 23.35 million MT for food-grain in 2014-15, which could be minimised using improved post-harvest technologies.

Post-harvest activities are an integral part of a food production system, and the aim should be to promote best practices for post-harvest handling and management along the entire food supply chain, focussing on a broad spectrum of operations and stakeholders in traditional and modern marketing systems. The ultimate goal of the system is to deliver high quality, safe food to consumers with low cost technology. Technological interventions are required at all stages of crop handling such as harvesting, threshing, winnowing, bagging, transportation, storage and processing.

Post-harvest losses are a measurable reduction in foodstuffs and may affect either quantity or quality. They arise from the fact that freshly harvested agricultural produce is a living thing that breathes and undergoes changes during post-harvest handling. Loss should not be integrated with damage, which is the visible sign of deterioration, e.g., chewed grain. Damage restricts the use of a product, whereas loss makes its use impossible.

In tropical countries, 75 percent of basic food comes from cereals and pulses. In the food chain, quantities of food are measured in terms of weight but this does not mean that organic structure and nutrients be ignored. The main cereals are wheat, maize, rice, barley, sorghum, millet, oats and rye; pulses cover the various species of pea, bean, broad bean and lentil. Food loss refers to total modification or decrease of food quantity or quality, which makes it unfit for human consumption. Quantitative loss is a loss in terms of physical substance, meaning a reduction in weight and volume, and can be assessed and measured. Qualitative loss, however, is concerned particularly with the food and reproductive value of products and requires a different kind of evaluation. A few of the parameters affecting the storage of food-grains are moisture content, damaged grains and other direct and indirect losses.

In agriculture, moisture content or humidity rate is usually indicated as a proportion of the moist product, i.e., the moisture content is the proportion of the weight of moisture to the total weight of dry matter and moisture. Damage is a clear deterioration in the product, e.g., broken or pitted grain, which affects more its quality than its quantity and can in the long-term, result in a definite loss. Both damage and loss should be quantified in terms of weight and cost. Direct losses occur when the disappearance of a foodstuff is caused by leakage (for example, spillage from bags) or consumption by pests (insects, rodents, birds), whereas indirect losses occur when a reduction in quality leads to the consumer’s refusal to purchase.

In order to control the moisture content at the time of storage, many evolved dryers have come into operation such as:

• Continuous Grain Dryer: The dryer has capacities of 0.8 MT/hour for wheat, 0.8 MT/hour for paddy, 0.96 MT/hour for maize, and 0.8 MT/hour for red gram;
• Cup and Cone Dryer for Paddy Drying: 950 kg of parboiled paddy of 30 percent moisture content can be dried to 14 percent in 2 hours at a drying temperature of 120° C and an airflow rate of 127.5 m3/min;
• IGSI Batch Dryer: The dryer can accommodate 1.5 tonne of paddy per batch, which takes 4 hours to dry;
• Community Grain Dryer: It takes 6.5 hours to dry 1 MT of paddy from 24 percent to 1496 moisture content;
• Re-circulating Batch Dryer: In this, paddy is circulated till the moisture content falls to 14 percent, the capacity of the dryer is 1.25 MT/batch;
• Solar Cabinet Dryer (CIAE).

The pre-treatment necessary for better storage life is cleaning and drying of the grain, but storage structure design and its construction also plays a vital role in reducing or increasing the losses during storage. In India, around 60-70 percent of food-grains produced are stored at home level in indigenous storage structures. The major construction materials for storage structures in rural areas are mud, bamboo, stones and plant materials, which are neither rodent-proof, nor secure from fungal and insect attack. On an average, out of a total six percent loss of food-grain in such storage structures, about half is due to rodents, and another half is due to insects and fungi.

Some of the innovative and small-sized storage structures with wide acceptance by farmers are:

• Coal Tar Drum Bin (150 kg capacity);
• Hapur Bin (200 kg capacity);
• Chittore Stone Bin (250 kg capacity);
• Double-Walled, Polyethylene-lined Bamboo Bin (500 kg capacity);
• Pusa Bins (1-4 MT capacity).

Some of the large storage structures with wide usage are:

• Cover and Plinth Storage;
• Community Storage Structures (25-100 MT capacity);
• Rural Godowns (100-1000 MT capacity);
• Silos (The silo system is equipped with other preparatory units like cleaning and drying equipment, capacity can be increased or decreased as per requirement).

Storage plays a vital role in promoting agriculture marketing and ensuring food security in the country. The warehousing capacity available in India, in public, cooperative and private sector is over 112 million MT and another 35 million MT of warehousing capacity is required during the 12th Five Year Plan for storing all major crops highlighting the huge demand-supply mismatch. About 70 percent of warehousing space is with government agencies. Moreover, the warehouses in India lack in optimal size, adequate design, ventilation facility, inventory management and storage systems as they are built following the traditional norms without proper specifications, and even some of the modern warehouses do not meet international standards.

In India, around 20-30 percent of total food-grain harvest is wasted due to inadequate storage capacity, regional imbalance in warehouses, lack of adequate scientific storage and inefficient logistics management. Each grain bag is handled at least six times before it finally opened for processing, which leads to higher storage and transportation charges and adds to wastage of during transit and handling.

Defying all odds, warehousing will continue to be the backbone for developing trade and commerce and the agro processing industry, as it plays a crucial role in strengthening agricultural supply chains, ensuring food security and price stabilisation. There is an intense competition amid the warehousing industry due to low entry barriers (lower capital outlay and lower regulatory environment) and high fragmentation. Moreover, the unorganised segments also pose a great threat and competition to modern warehousing because of lower overheads and competitive warehousing rates in the country.

About Author:
Dr Hanish Kumar Sinha is Head – Research & Development at National Bulk Handling Corporation.