How manage post-harvest losses of food crops, fruits & vegetables

Food wastage is not acceptable anywhere in the world considering resources required to grow foods. It is more so in Nigeria where millions of people go to bed hungry and starved. FEMI IBIROGBA, Head, Agro-Economy Desk, writes on how to preserve common perishable food crops, fruits and vegetables.

Post-harvest losses could be described as a disservice to humanity in a world where millions, if not billions of people around the world either suffer from outright or hidden hunger (malnutrition).

Nigeria is, according to the World Bank record, home to over 87 million extremely poor people, and one of the criteria for this classification is lack of access to quality foods.

Professor Gloria Elemo, Director General of the Federal Institute of Industrial Research, Oshodi (FIIRO), had revealed that economic value of post-harvest losses in 2017 was $9 billion.

From vegetables, fruits and food crops, a large percentage of farm products are either wasted on the farm, in transit or at commodity markets.

A visit to the Ketu market in Lagos would convince anyone that the volume of food wasted in Nigeria is massive. Tomatoes, because of poor handling and the use of raffia baskets for transportation, are heavily wasted. Watermelons are massively wasted, for there is hardly any juice company off-taking and processing the products in Nigeria. In fact, post-harvest losses in Nigeria are estimated to be hovering around 50 per cent of the total foods produced.

Give-away prices
Apart from losses, farmers are compelled to sell most of their food crops at give-away prices as a result of inability to preserve. This inability is compounded by the fact that most of the farmers do harvest their farms in the same periods, creating an over-supply at a given time, and hence selling at extremely give-away prices, most of the times below production cost.

Losses and low prices as disincentives to agro-investments
Losses of harvests and selling the remnants at ridiculous prices are one of the most devastating factors discouraging new investments into and expansion of farm operations. Inability to break even or make profit is a negative stimulus that has been receiving negative responses of backing out of farming and scaling down of farm operations.

Mr Femi Ajileye, a Lagos-based retiree who made an effort to cultivate yam in Kogi State in the 2017/2018 planting season, invested about N300,000 in the business. To his surprise, he realised about N90,000 from the sale of the yam.

Discouraged, Mr Ajileye said he would not make attempt to cultivate yam in the next planting season.

Post-harvest management
Considering the economic implications of the losses, post-harvest management becomes inevitable. It means tackling the challenges with an eclectic approach by exploring different ways to prevent either losses or selling at give-away prices. The following are possible ways forward.

Locating an off-takers
Part of a good plan for agribusinesses is marketing planning. Producing what nobody buys or what somebody buys below the cost is economically nonsensical. Farmers should, therefore, do marketing plans based on surveys of where and when to sell at good prices. Farmers should be ready to leave their comfort zones by moving their products to urban areas where they command higher prices.

There are off-takers (processors) for yam, cassava, sweet potato and plantain, who, in turn, process the same into pounded yam powder (Pandoyam); ethanol or starch/flour; potato flour/ethanol and plantain chips or powder, respectively.

Yam, plantain, sweet potato and particularly cassava, are, to a great extent, industrialised food crops that farmers should make deliberate efforts to market.

Processing cassava, sweet potatoes for better shelf life, profitability
Though processing could mean extra labour and cost, it helps to eliminate both losses and poor prices. Through processing, moisture contents are minimised to acceptable levels of about eight to 10 per cent, and hence the products are preserved. Preserved products are not sold in a hurry. In fact, they tend to command a far better value if packaged decently and attractively.

Converting cassava to garri in Nigeria means business, and a farmer gets a higher value doing this.

Mr Kolawole Adeniji, a farmer and processor, told The Guardian that a kilogramme of garri is now N200. He said 300 or more kilogrammes are obtainable from one metric tonne of cassava. This would give the farmer about N60,000. If he sells the cassava raw, he would sell a tonne between N17,000 and N25,000. Minus the cost of processing the cassava, which is about N10,000, the farmer would go home with additional N25,000, at least.

Country Manager of the International Potato Centre in Nigeria (CIP), Dr (Mrs) Olapeju Phorbee, told The Guardian that sweet potato is processed into garri the same way cassava is processed, and that the sweep potato garri is even more nutritious and aromatic than cassava’s.

Rather than selling a tonne of sweet potatoes at about N15,000, a farmer can process and make a gross of N60,000.

Nigeria is one of the largest producers of sweet potato, but one of the least industrially utilizing roots crops, leading to annual gross loss of the food security crops.

Unlike cassava that takes up to one year before maturation, sweet potato takes about three to four months to mature, and hence a crop with paradigm shift potential if losses are prevented, Phorbee said.

It is a paradigm shift crop in two ways. The bio-fortified varieties could be used to tackle Vitamin A deficiency and hidden hunger, and farmers could be empowered with more utilization of the root crop, she said.

Preserving fruits and vegetable
Fruits and vegetables, by their nature, are highly perishable, and this becomes more pronounced without adequate technologies and value addition.

However, the Nigeria Stored Products Research Institute (NSPRI), Ilorin, has developed solar and hybrid multipurpose dryers to preserve and prolong the shelf life of some fruits and vegetables. Wax coating, the institute said, can delay ripening of tomatoes, banana and plantains for a few more days or weeks, without negative health implications.

Leaves of vegetables can be solar-dried, packaged and marketed with longer shelf life. Peppers and scent leaves are also preserved using dryers, flash dryers and gas dryers. The institute has provided some guidelines for processing and preserving the following fruits and vegetable, among others.

Dried mango chips
Several tonnes of mangoes are wasted every year right from the farm gates to aggregate centres and commodity markets. Ogbomosho, in Oyo State, is known for the best variety of mangoes in Nigeria, and the production per annum is usually huge. But wastage of the fruit is equally colossal because mango is highly perishable, fragile and poor in shelf life without appropriate technologies.

NSPRI has developed a template for drying mangoes into chips. With the template also comes some processing equipment.

NSPRI guidelines state that the processor should select fruits about or just ripening, wash and slice the pulps into preferred shapes and then dry.

Drying can be done under the sun on a raised platform since mangoes are usually available in the dry season when sunshine is assured, but to produce chips of exportable quality and quantity, the processor should use solar trays, multipurpose or hybrid dryers.

Dried chips should be packaged in food grade polythene bags and sealed to prevent re-absorption of moisture after packaging.

There is high demand for mango chips in South Africa and some European countries. The chips are used for juice or eaten raw after rehydration, especially by vegetarians.

Packed mango sachets should be put in cardboard cartons or light wooden crates for transport into the market, NSPRI stated.

Dried tomatoes
Farmers and tomato aggregators can prevent loss of millions of naira yearly by processing ripe tomatoes into dried forms. Inability to sell tomatoes as quickly as possible leads to rottenness or selling at low prices, resulting in huge wastages.

As a way out of the usual mess, NSPRI advises that farmers, their cooperatives or entrepreneurs could prevent the wastage, make tomatoes available year round in dried forms, create processing and marketing jobs, and increase the profitability of primary producers by preserving tomatoes through drying.

Tomatoes to process should be ripe, red, firm and fresh, NSPRI recommends, and they should be washed, drained and sliced into small pieces of about 0.5cm thick.

“You can dry tomatoes slices on clean, [and] raised platform[s] under the sun. For large scale drying and more hygienic products, dry tomato slices with solar trays, multipurpose dryers or hybrid dryers,” the NSPRI production guidelines stated.

Dried vegetable leaves
Leafy vegetables are the most perishable of all the agricultural produce. In the rainy seasons, losses are huge, but these are preventable with little efforts and investments.

For a long storage life and export, vegetable leaves can be dried and stored and stored.

Researchers at the institute said to produce dried vegetable leaves, farmers or processors should use freshly harvested green leaves by cutting them into desirable pieces and parboil.

The parboiled vegetables should be drained, and dried using the various available dryers aforementioned. The dried leaves should be allowed to cool, and should be packed in food grade polythene bags and sealed.

Lagos spinach, spinach, water and bitter leaves, scent leaves, ugu, jute leaves, sweet potato leaves and other vegetables are processed, preserved and stored for future uses using the above processes.

Traditional ways of prolonging shelf life
There are traditional techniques of preserving tubers of yam, sweet potato and water-yam, to mention but a few. Among these techniques is burying the roots or tubers under a tree, after laying some dry leaves on the floor of the pit. The tubers and roots are also covered with leaves before proper burying.

Bans are also improvised in ventilated places, especially under shady trees to prolong the shelf life of yam and potato, making it possible for farmers to avoid selling at give-away prices.