As the world marks the International Day of Awareness of Food Loss and Waste on 29 September under the theme “Transformative Potential of Reducing Food Loss and Waste”, Professor Lembe Magwaza, Chair of the South Africa-Germany Bilateral Research Chair in Sustainable and Resilient Food Systems (SARChI SuReFoodS), reflects on this global challenge and its profound impact on South Africa and the wider African continent.

In this article, Prof Magwaza explains how food is lost and wasted across the value chain. He also outlines his vision for equipping smallholder farmers with technology, strengthening their contribution to food security and bridging the divide between South Africa’s “two agricultures”.

Prof Magwaza, an NRF-rated scholar and internationally recognised plant scientist and postharvest technology expert, became Chair of SARChI SuReFoodS this year. Based at the University of Mpumalanga, the Chair is funded by the National Research Foundation (NRF) and Germany through the German Academic Exchange Service (DAAD). It is one of approximately 250 active Research Chairs established under the South African Research Chairs Initiative (SARChI). Launched in 2006 by the Department of Science, Technology and Innovation (DSTI) and the NRF, SARChI strengthens research and innovation capacity at South African public universities by supporting leading researchers and Chairs that produce high-quality research, innovation and postgraduate researchers.

Prof Magwaza reflects on the International Day of Awareness of Food Loss and Waste in a question-and-answer format.

How do you conceptualise food loss and food waste within the context of your research? 

Food loss and waste are major threats to food security, nutrition and sustainable food systems in South Africa, across Africa and globally. The terms are distinct: “food loss” is a reduction in the quantity or quality of food from production and harvest through handling, storage, processing, transport and distribution, before retail. “Food waste” occurs mainly at retail, food service and household levels.

An estimated 30% to 50% of global food production is lost or wasted instead of contributing to food and nutrition security. Losses for dry grain crops such as maize, wheat and millet are lower but can still reach 30% — about one-third of production that is discarded, sent to landfill or never reaches consumers. For highly perishable horticultural crops, losses can rise to 50% in worst-case scenarios, particularly in smallholder farming systems. Their high moisture content encourages pathogens, while poor postharvest handling, inadequate cold-chain management and breaks in temperature control accelerate deterioration, senescence and spoilage.

As postharvest scientists, our role is to preserve quality by slowing ripening, senescence and deterioration. The high moisture content of horticultural crops supports the growth of pathogenic microorganisms that cause spoilage. In some cases, these microorganisms also produce harmful compounds, including mycotoxins, which may be lethal or carcinogenic and therefore threaten food safety. Food loss should consequently include not only the complete loss of food along the value chain, but also losses in nutritional and economic value, safety and other quality attributes.

You argue that food waste occurs primarily at the retail, food service and consumer levels. How do consumers contribute to food waste?  

Consumers contribute to food waste through their purchasing habits and expectations of quality and appearance. Convenience and bulk pricing are common drivers. A kilogram of packaged tomatoes, peppers or another product may cost less per unit than a single item because retailers want to sell in bulk. However, someone living alone in Sandton or Mbombela may not need a kilogram and may discard what they cannot consume.

Consumer demand for produce of a particular shape, colour, aroma or packaging also drives waste. Biological products are never perfectly uniform, yet strict market specifications can leave nutritious, healthy produce without a buyer simply because it is cosmetically imperfect. We therefore need agro-processing and value-addition technologies that convert surplus, cosmetically rejected and highly perishable produce into nutritious, shelf-stable products.

What is the emerging picture regarding societal demand for redress in relation to food loss and waste? 

We must recognise the dual nature of South Africa’s agricultural and food system. Agricultural economist Wandile Sihlobo recently explored this in his book The Country of Two Agricultures. South Africa has a highly developed commercial agricultural sector alongside a large smallholder sector dominated by black farmers. Many smallholder farmers have limited access to cold-chain infrastructure, technology, finance, markets and technical knowledge. These constraints increase food losses and make it difficult to supply formal markets consistently with quality produce.

How, then, do we support these farmers? This is where SARChI SuReFoodS, the portfolio I lead, can contribute. Our research develops sustainable approaches that help farmers preserve food quality while improving the economic viability of their operations.

Because some farmers lack electricity, we must explore suitable technologies such as evaporative and charcoal-based cooling. These affordable, environmentally friendly options can preserve perishable produce and help more smallholder farmers participate in cold-chain and mainstream food value chains.

We must also generate evidence to inform policy and teach smallholder farmers how to prevent food loss and waste so that their operations remain economically sustainable. This would help them enter mainstream agriculture, narrow the divide between the “two agricultures” and support a just and equitable food system.

Given that the Research Chair is newly established, what key outcomes would you aim to achieve over the next five years, and what indicators would you use to evaluate the Chair’s research impact and success? 

My specialist field has been postharvest technology, which focuses on preserving food after harvest. Over time, however, I came to understand that postharvest technologies alone do not determine food quality; preharvest management is equally important. We must produce high-quality food and then preserve that quality throughout the value chain. Poor quality at the outset is very difficult to correct or maintain after harvest.

My measure of success for this portfolio returns to the issue of South Africa’s “two agricultures”. I want smallholder farmers in Nkomazi and Bushbuckridge in Mpumalanga, Bergville and Msinga in KwaZulu-Natal, Ngcobo in the Eastern Cape, and elsewhere in South Africa to run profitable, sustainable enterprises. They should be able to enter mainstream agricultural and food supply chains and supply quality food consistently throughout the year. South Africa’s diverse climatic conditions make this achievable, but academic institutions such as UMP, working through initiatives such as SARChI SuReFoodS, must partner closely with farmers to build the knowledge needed for sustainable operations. My main measure of success would be seeing farmers move from subsistence production to economically viable enterprises that contribute meaningfully to food and nutrition security and the agricultural economy.

Lastly, I want a South African food system that is less dependent on the current retail model. Smallholder farmers should view each community as an ecosystem in which food is produced and sold locally. This would improve local nutrition security and, if replicated across communities, strengthen food and nutrition security throughout South Africa.

Let’s talk smallholder farmers and technology. Are there any technological gaps that you think need to be addressed as we move forward?

Several technological gaps need attention, many of which reflect the divide between South Africa’s “two agricultures”. One of the most fundamental is cold-chain management: maintaining each crop at its optimal temperature throughout storage and transport.

Commercial farmers are generally better equipped to manage cold chains because their production volumes justify dedicated infrastructure. Each commodity has specific temperature requirements: bananas, for example, need considerably warmer transport conditions than apples. Storing commodities with different requirements in the same refrigeration system makes it difficult to maintain optimal conditions for each crop.

Smallholder farmers may lack knowledge of each crop’s temperature requirements and, because they produce limited volumes, may store different crops together. Many also lack refrigeration infrastructure altogether. A farmer cultivating vegetables on a small plot may not earn enough to invest in a dedicated cold room. We therefore need aggregation and service enterprises that collect produce from several smallholder farmers and provide properly managed refrigeration and storage facilities.

An entrepreneur could, for example, operate cold rooms at different temperatures for different commodities. Shared infrastructure of this kind would make postharvest technology more accessible to smallholder farmers while creating economic opportunities in rural communities.