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18 June 2019 | Story Leonie Bolleurs | Photo Leonie Bolleurs
Dr Christine Engelbrecht from the Agricultural Research Council
Dr Christine Engelbrecht from the Agricultural Research Council presented the keynote lecture on climate dynamics, predicting that El Niños will double in frequency towards the end of the century.

The world will need nearly double the current food supply by 2050 to feed an ever-increasing world population. This is a mammoth, almost impossible task.

Building on knowledge

According to UFS Rector and Vice-Chancellor, Prof Francis Petersen, if we approach challenges such as these with scientific level-headedness, systematically build on knowledge and experience gained, and draw on similar inputs from other specialist fields, the seemingly impossible becomes possible.

“To what extent do we integrate our knowledge across sectors – within the university and outside the university; on the continent as well as globally?” he asked the 300-plus delegates, which included animal scientists, students, and various other role players in the livestock sector, at the 51st South African Society of Animal Science (SASAS) congress on the Bloemfontein Campus of the University of the Free State (UFS). 

Willingness to adapt to new strategies


The theme of this year’s congress was: Managing the ecological footprint of livestock through efficient production. The congress provided a platform for discussions on the impact of livestock production – bringing in elements of critical thinking, as well as the willingness to adopt new strategies. 

During the congress, workshops on topics such as silage, predation management, intensive sheep production, prickly-pear utilisation, and animal welfare provided delegates with the opportunity to discuss challenges faced by the South African livestock producer.

Dr Christine Engelbrecht (Meteorology) from the Agricultural Research Council presented the first keynote address, focusing on climate dynamics. 

“We have high-impact weather systems across Southern Africa. It is projected that strong El Niños are to double in frequency towards the end of the 21st century,” said Dr Engelbrecht. 

She further predicted temperature increases of between 4 and 7 degrees Celsius in the interior before the end of the century. Over the Free State, Northern Cape, and North-West Province, we can expect shorter frost seasons, significant increases in maximum temperatures for both summer and winter, as well as more frequent El Niño-induced droughts. 

Ecological footprint of food

Improved production outputs need to be achieved by using less land, water, and available energy, while ensuring that the degradation and pollution of natural resources are limited. A scientific approach would be a viable option to improve the efficiency of livestock production.

SASAS President, Prof Este van Marle-Köster from the University of Pretoria, pointed out that all food had an ecological impact.

Dr Frikkie Maré, Head of the Department of Agricultural Economics at the UFS, presented a keynote lecture on managing the footprint of beef through efficient production. Comparing the water footprint of different cattle breeds, his question was what could be done to reduce this. 

Animal welfare was introduced to the congress for the first time. Prof Cathy Dwyer from Scotland’s Rural College presented a session on, ‘Can animal welfare contribute to improved production efficiency?’

The oldest conception of animal welfare is the five freedoms adapted to the five welfare needs of animals, namely a suitable environment, a suitable diet, exhibiting normal behaviour patterns, being with or being apart from other animals, and protection from pain, injury, suffering, and disease. Studies demonstrate that animal welfare can be an important and effective part of production efficiency, and that animal welfare should be seen as an integral component of improving the sustainability of livestock. 

Prof HO de Waal from the Predation Management Centre at the UFS presented a session on the impact of predation on livestock production, with the tile: The need for coordinated predation management in South Africa – quo vadis? He said: “The current approach to predation management is fragmented and uncoordinated. Solutions for the management of human-wildlife conflict require a South African institutional memory. Most of the information on predation and the hunting of predators is held by specialist predator hunters and farmers. In a system of coordinated predation management, farmers and government are equal partners, each with specific responsibilities.”

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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