School of Engineering


Professor Tilahun Seyoum Workneh (centre) with family and colleagues.

Innovative Postharvest Technologies the Answer – Bioresources Engineer

Integrated, innovative postharvest technologies are capable of reducing losses in horticultural crops, says Professor Tilahun Seyoum Workneh.

A Bioresources Engineer with a BSc in Agricultural Engineering from Haramaya University in Ethiopia, Workneh was addressing fellow academics and students at his inaugural lecture, which officially ushered him into the UKZN professoriate.

With a MScEng degree in Agricultural and Food Engineering from the University College of Dublin in Ireland and a PhD in Food Science from the University of the Free State, Workneh – a C2 NRF-rated researcher – has during the course of his career developed low-cost appropriate cooling technologies, proving that they can assist in the extension of the shelf life of fruit and vegetables.

He has also developed an integrated postharvest technology by combining pre-harvest and postharvest treatments of fruit and vegetables.

‘African countries have a range of climates that are favourable for the production of horticultural crops,’ said Workneh. ‘These countries have attempted to intensify production but production in Africa is lower when compared to other continents. Also, the production has not been consistent over successive years.’

The reason for this was that little emphasis is placed on innovation and implementation of post-harvest technologies in the horticultural value chain, vital to stimulate the desired high harvest yields and reduce losses.

‘The availability of affordable post-harvest technology is of the upmost importance to meet consistently high productivity, and to make available high-quality fresh produce in markets. ‘Advanced post-harvest technologies which utilise complex machines that consume high energy are expensive for stakeholders in sub-Saharan Africa. Affordable low-cost innovative post-harvest technologies have been developed and are ready for implementation as intermediate technology to solve produce losses and ease food security challenges the continent is facing,’ he said.

Workneh described several innovative and affordable coolers that have been developed, including a naturally ventilated, single-pad and multi-pad evaporative cooler.

‘Integrated post-harvest technologies combining environmentally friendly disinfection treatment and evaporative cooling have proven effective in extending the shelf life of horticultural crops. When developed, these integrated post-harvest technologies were found to be effective under hot, arid and semi-arid conditions.’

Workneh, who has more than 28 years of experience in multidisciplinary research in the area of agricultural engineering and postharvest technology, has received the School of Engineering’s Research Excellence Award eight times.

His research interests include heat and mass transfer; hybrid drying technology; food processing and preservation technologies; optimisation and modelling of food processes; postharvest technology and process engineering of fruit and vegetables; food quality and food safety engineering; engineered systems for food production; environmental modification; and control for biological systems.

He has published more than 110 scientific articles in peer-reviewed international and local journals in the multi-disciplinary research areas of agricultural processing, food science and postharvest technology, environmental control for biological commodities, and renewable energy.

Workneh has supervised 35 MSc and PhD students and four postdoctoral fellows, and has received a UKZN School of Engineering Best Lecturer award twice. He is a fellow of the South African Institute of Agricultural Engineers, a professional member of the South African Association of Food Science and Technology, and a member of the American Society of Agricultural and Biological Engineering.

Words: Sally Frost

Photograph: Albert Hirasen