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22 January 2020 | Story Leonie Bolleurs | Photo Leonie Bolleurs
Soil Confrence at UFS
At the Combined Congress with the theme ‘Basic and applied sciences – Fundamentals of sustainable agriculture’, were from the left: Prof Klaus Kellner, Prof Prakash Naidoo, Dr Cobus Botha from the Agriculture Research Council, Prof Vaughan Hattingh, and Mr Matome Ramokgopa.

“We are at the beginning of a new decade that will in all likelihood be pivotal for aspects such as food security, climate change, and the sustainable use of natural resources – aspects that the societies you represent are of course keenly involved with – and in terms of which you can play an increasingly valuable role.” 

These were the words of Vice-Rector: Operations at the University of the Free State (UFS), Prof Prakash Naidoo, on opening a Combined Congress of the Soil Science Society of South Africa (SSSSA), the South African Society of Crop Production (SASCP), the Southern African Weed Science Society (SAWSS), and the Southern African Society for Horticultural Sciences (SASHS).

The UFS Department of Soil, Crop and Climate Sciences is hosting the congress, with scientific content of four disciplines (soil, crop, weed, and horticulture) presented by both local and international guest speakers.

The theme of this year’s congress taking place on the UFS Bloemfontein Campus, is Basic and applied sciences – Fundamentals of sustainable agriculture.

Prof Naidoo continues: “It has been predicted that the world will need almost double the current food supply by 2050 to feed an ever-increasing world population. This clearly makes the scientific work done in the agricultural sector and the organisations affiliated with it, more vital than ever. We need to do what we can to ensure food security and sustainability.”

“A congress like yours is an opportunity to tap into the perspectives and research results of collaborators from different fields, and from different levels of skill and experience – with the aim of ultimately benefiting wider communities.”

Leader in agriculture sector

Prof Vaughan Hattingh, representing SASHS (Chief Executive Officer of Citrus Research International); Mr Matome Ramokgopa, representing SASCP (General Manager of Enza Zanden SA); and Prof Klaus Kellner, representing SSSSA (Department of Botany at the North-West University), delivered the combined opening address.

Prof Hattingh, speaking on ‘Industry–University partnership opportunity road ahead for horticultural research’, says citrus is a major horticultural product internationally and the biggest horticultural export from South Africa. The citrus industry, the second largest exporter of citrus in the world, generates R20 bn per year and is the biggest funder of research in this area. 

Prof Hattingh states that university partnerships, developing science to assist the industry, are key. “The future of horticultural industries and horticultural research at universities depends on successful university-industry partnerships.”

Mr Ramokgopa talked about ‘Innovative solutions for vegetable seed production for a growing population’, saying that Enza Zanden employed several techniques in vegetable production in response to the needs of retailers and consumers. These include smaller tomatoes (for snacking purposes), smaller leaf size of lettuce (thus a smaller area for decay), plastic-free packaging of cucumber with a longer shelf life, and more uniform onions (suitable for onion rings). 

Prof Kellner focused on ‘Scientifically sound policies and practices to ensure food security and sustainable agriculture’. He said: “It is getting warmer in Southern Africa and Europe. We need to realise it and adapt practices accordingly.”

More discussions on sustainable agriculture

Other interesting topics covered at the congress include, ‘Developing propagation technologies for indigenous plants used in the natural products industry’; ‘The influence of foliar and application rate of nitrogen fertiliser on seed and oil yield of canola’; ‘Sweet potato production in sacks: potential utilisation of limited space in rural, urban and peri-urban areas’; ‘The efficacy of postharvest wax application in the reduction of chilling injury incidence in lemon fruit’; and ‘Herbicide use within the commercial forestry sector in South Africa’.

Congress attendees can also look forward to the ‘Soil fertility and crop nutrition symposium: principles and practices’ on Wednesday 22 January 2020.

The congress kicked off on 21 January, and will come to an end on Thursday 23 January 2020. For more information on the sessions, see programme.

News Archive

Research eradicates bacteria from avocado facility
2017-01-17

 Description: Listeria monocytogenes Tags: Listeria monocytogenes

Listeria monocytogenes as seen under an electron
microscope. The photo was taken with a transmission
electron microscope at the microscopy unit of the UFS.
Bacteriophages (lollipop-like structures) can be seen
next to the bacterial cells.
Photo: Supplied

“The aim of my project was to identify and characterise the contamination problem in an avocado-processing facility and then to find a solution,” said Dr Amy Strydom, postdoctoral fellow in the Department of Microbial Biochemical and Food Biotechnology at the University of the Free State (UFS).

Her PhD, “Control of Listeria monocytogenes in an Avocado-processing Facility”, aimed to identify and characterise the contamination problem in a facility where avocados were processed into guacamole. Dr Strydom completed her MSc in food science in 2009 at Stellenbosch University and this was the catalyst for her starting her PhD in microbiology in 2012 at the UFS. The research was conducted over a period of four years and she graduated in 2016. The research project was funded by the National Research Foundation.

The opportunity to work closely with the food industry further motivated Dr Strydom to conduct her research. The research has made a significant contribution to a food producer (avocado facility) that will sell products that are not contaminated with any pathogens. The public will then buy food that is safe for human consumption.


What is Listeria monocytogenes?

Listeria monocytogenes is a food-borne pathogenic bacterium. When a food product is contaminated with L. monocytogenes, it will not be altered in ways that are obvious to the consumer, such as taste and smell. When ingested, however, it can cause a wide range of illnesses in people with impaired immune systems. “Risk groups include newborn babies, the elderly, and people suffering from diseases that weaken their immune systems,” Dr Strydom said. The processing adjustments based on her findings resulted in decreased numbers of Listeria in the facility.

The bacteria can also survive and grow at refrigeration temperatures, making them dangerous food pathogens, organisms which can cause illnesses [in humans]. Dr Strydom worked closely with the facility and developed an in-house monitoring system by means of which the facility could test their products and the processing environment. She also evaluated bacteriophages as a biological control agent in the processing facility. Bacteriophages are viruses that can only infect specific strains of bacteria. Despite bacteriophage products specifically intended for the use of controlling L. monocytogenes being commercially available in the food industry, Dr Strydom found that only 26% of the L. monocytogenes population in the facility was destroyed by the ListexP100TM product. “I concluded that the genetic diversity of the bacteria in the facility was too high and that the bacteriophages could not be used as a control measure. However, there is much we do not understand about bacteriophages, and with a few adjustments, we might be able to use them in the food industry.”

Microbiological and molecular characterisation of L. monocytogenes

The bacteria were isolated and purified using basic microbiological culturing. Characterisation was done based on specific genes present in the bacterial genome. “I amplified these genes with polymerase chain reaction (PCR), using various primers targeting these specific genes,” Dr Strydom said. Some amplification results were analysed with a subsequent restriction digestion where the genes were cut in specific areas with enzymes to create fragments. The lengths of these fragments can be used to differentiate between strains. “I also compared the whole genomes of some of the bacterial strains.” The bacteriophages were then isolated from waste water samples at the facility using the isolated bacterial strains. “However, I was not able to isolate a bacteriophage that could infect the bacteria in the facility.

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