Reducing post-harvest losses: a priority for Africa

Post-harvest loss and its consequences for development is a widely recognised challenge. So what are the solutions already underway to ensure that food produced reaches the end user?

A €2 PICS bag can hold around 90 kg and creates a hermetic seal, starving insects of oxygen to keep crops safe © Tom Campbell, Purdue University
A €2 PICS bag can hold around 90 kg and creates a hermetic seal, starving insects of oxygen to keep crops safe © Tom Campbell, Purdue University

Thursday, 29 March 2018

With up to half of all crops being lost before they can be sold or eaten in Africa, there’s an urgent need to identify solutions that can deliver impact at scale.

Around a third of all food produced globally is lost or wasted. In Africa, the figure is estimated to be as high as 50%. In developing countries, the majority of food ‘loss and waste’ is in fact loss, and it happens mainly because of poor crop harvest and handling practices early in the value chain. Access for smallholders to effective and affordable post-harvest technologies is therefore a development priority.

Reducing post-harvest losses increases food supply, avoids the waste of inputs already used, and can enable smallholders to access higher value markets. The challenge is to identify those technologies and processes that can transform value chains and smallholder livelihoods on a wide scale.

“Such transformational impact can come from trailblazing technologies or business models that change conventional thinking,” says Sara Farley, chief operating officer and co-founder of the Global Knowledge Initiatve (GKI), which recently published a report identifying high-potential post-harvest innovations. “And sometimes, other innovations that seem more incremental in nature are also capable of ushering in large-scale and long-term change. We feel the scale of the challenge is such that it’s important to identify the most promising existing innovations – the ones to invest in today – while also looking further ahead at next-generation emerging innovations,” Farley explains.


The GKI report calls for investment into ‘quick wins’ that show promise for immediate impact – and one example of that would be ColdHubs, which is providing affordable refrigeration to farmers in Nigeria.

ColdHubs sells access to refrigeration hubs on a pay-as-you-store basis, solving the problem for individual farmers of large upfront investment in their own equipment. The business currently has five hubs serving 320 customers, and its demonstrable impact has recently attracted investment which means three more hubs are in the process of being developed. “A 20 kg crate of tomatoes sells in Nigeria for US$40-50 [€32-40] during the peak season,” says Nnaemeka Ikebwuonu, CEO of ColdHubs. “That’s the price from 7am until about 1pm. By this time, rot has set in and it is sold for 50% less. By 5-6pm, it will be sold for 80% less. But ColdHubs enables farmers to store that 20 kg crate for US$0.50 [€0.40].” In other words, if a farmer has surplus tomatoes, an affordable €0.40 investment per crate will enable them to stagger sales and prevent a substantial loss in income.

US start-up company Evaptainers is taking a traditional refrigeration technique – evaporative cooling – and using it to manufacture pre-built, lightweight mobile refrigeration devices. Its EV-8 is a collapsible box made with a synthetic fabric, and users just pour water into the space between the inner and outer layers to activate the cooling process. It will sell for €20-28 and a pilot project using 300-500 units is planned in Morocco this year, with a view to an eventual wider roll-out in other countries. “Our hope is that this pre-built device will be easier for wide distribution than traditional evaporative cooling chambers, which need construction,” says CEO and co-founder Quang Truong.

Adding value

Being able to turn perishable or surplus crops (including residues) into a new product can enable farmers to access entirely new markets and sources of income. CAVA II, for example, will enable up to 250,000 farmers across five African countries to earn additional income from processing cassava into high-quality cassava flour to be sold to brewers and bakers.

In Nigeria, the International Livestock Research Institute (ILRI) has led a project creating value out of previously discarded cassava peels by processing them into animal feed. Using a new type of pressing equipment, 500 l of water can be squeezed out 1 t of fresh grated peels in just half an hour, and the resulting cake can be dried in as little as 6 hours rather than 3 days. “At Ojikpata in Kogi State, a women’s cooperative that established a small-scale peel processing outfit has attained production of 1 t per week of fine high-quality cassava peel mash which it is marketing to a fish feed manufacturing company in Lagos,” says Dr Iheanacho Okike, senior agricultural economist at ILRI. “The cooperative has 22 members generating peels from which they now earn N50,000 [€112] per week.”

And in Kenya, funding from USAID for an automated air drier has enabled one enterprise – Sweet ‘n’ Dried – to develop a dried mango range, and to source its mangos from hundreds of local smallholders, who previously had no market for their excess produce.

Safe storage

For grains in particular, secure storage is crucial. Traditional forms of storage, such as cloth sacks, can lead to quantitative and qualitative losses from problems such as rodents, weevils and aflatoxin accumulation. It is a widespread problem, but relatively low-tech interventions have been shown to deliver a high impact. In Kenya, for example, the introduction of simple metal silos with support from the Swiss Agency for Development and Cooperation and the International Maize and Wheat Improvement Center has led to some farmers reducing their crop losses from 90% to zero.

Metal silos are however relatively expensive, with larger ones costing as much as €285. A €2 Purdue Improved Crop Storage (PICS) bag can hold around 90 kg and creates a hermetic seal, starving insects of oxygen to keep crops safe. Over the past 10 years, more than 5 million farmers in 56,000 villages in sub-Saharan Africa have been trained in their use, and more than 10 million PICS bags have been sold.

More specialised bags are now also emerging. Last year, the Rockefeller Institute awarded a €400,000 grant to the UK’s Natural Resources Institute (NRI) to scale up its Cassavabag, which has built-in curing technology. “Currently, up to 40% of cassava is wasted as it can deteriorate as soon as 24 hours after harvest,” says NRI’s Director Andrew Westby. “The NRI Cassavabag’s built-in curing technology will keep cassava fresh for at least 8 days after harvest and could be transformational for the 500 million people in sub-Saharan Africa who rely on cassava for food security and nutrition.”

Ultra low cost innovations

Competitions are also encouraging entrepreneurs and researchers to come up with new innovative post-harvest technologies, with some recent winners standing out with products that are not just effective, but also very low cost.

One of them, a biopesticide known as Molepse bio-resource, costs just €0.80 for a 6 month supply and came second in the 2017 East Africa Post-Harvest Technologies Competition. Developed by Donatus Njoroge, an industrial chemist at Mt Kenya University, the biopesticide can be applied as a liquid or powder and provides 95% protection for grains against weevils.

For the same price, farmers might soon also be buying the DryCard, which won first place in the 2017 All Africa Postharvest Innovation Challenge. When placed in a sealed container with dried goods, the simple laminated strip changes colour to indicate whether the goods are dry enough. “Since March [2017], we and our partners have sold or distributed around 10,000 cards,” says James Thompson, one of the scientists at UC Davis University who pioneered the technology. “Our goal now is to incubate local businesses to manufacture and sell DryCard.”

Ultimately, it will be farmers themselves who determine which innovations succeed. The impact of post-harvest technologies simply depend on solutions that work and that farmers actually want to invest in, states Westby. “The Cassavabag is inexpensive and, crucially, we’ve found that it really appeals to farmers,” he says. “That’s why it’s a solution that we think will really have an impact."

Caspar Van Vark

Other dossiers

Facts and Figures

A €2 PICS bag can hold around 90 kg and creates a hermetic seal, starving insects of oxygen to keep crops safe © Tom Campbell, Purdue University

SOURCE: Rockerfeller Foundation, 2016 & PYXERA Global, 2017

The Technical Centre for Agricultural and Rural Cooperation (CTA) is a joint international institution of the African, Caribbean and Pacific (ACP) Group of States and the European Union (EU). CTA operates under the framework of the Cotonou Agreement and is funded by the EU.