Harare — A 2019–2020 study into the prevalence of the food-borne pathogen Listeria monocytogenes in beef and beef products at some abattoirs and retailers in the provinces of Gauteng, Mpumalanga, and the North West produced findings with potentially alarming implications for consumers.
According to the research, 4,6% of cold carcasses sampled at seven abattoirs in one of the provinces was found to be contaminated with Listeria monocytogenes, according to a study conducted by the University of Pretoria's Faculty of Veterinary Science and the Agricultural Research Council-Onderstepoort Veterinary Institute (ARC-OVI). This indicates that beef and beef-related items sold at retail establishments in the province may include infected carcasses and hence could enter the food chain.
An outbreak of listeriosis that resulted in 1,065 confirmed cases and 218 fatalities in 2017–2018 served as the impetus for the study, which was supported by Red Meat Research and Development South Africa.
"Processed foods become contaminated by contact with equipment, the handling of raw products, or from post-processing settings in which the pathogen can survive despite the routine use of disinfectants," said Dr Rebone Moerane, Head of UP's Department of Production Animal Studies, who was part of the research team along with Professor Abiodun Adesiyun, an extraordinary professor in the department, Dr Nomakorinte Gcebe of the ARC-OVI, and four postgraduate students.
The incidence and risk factors for Listeria in cattle, silage, feeds, and water on farms in the three provinces, in killed animals and carcasses at processing facilities, and in tainted beef products at retail were also examined by University of Pretoria researchers. Samples of raw beef and beef products, including ready-to-eat goods, were gathered from stores of all sizes, as well as carcass swabs from abattoirs and samples of cattle ranches.
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According to research, there is very little chance that cattle on farms will be exposed to listeriosis. However, they noted that both the findings at retail establishments and the discovery of infected chilled carcasses at Gauteng abattoirs are alarming.
In stores in North West, Mpumalanga, and Gauteng, samples of beef and beef products were taken, and the prevalence of Listeria was 6%, 8.3%, and 9.3%, respectively. For cold beef and beef products, the prevalence was 4.3%, 11%, and 9.3%.
"Some of the contaminated products were RTE items – including polony, which is widely consumed, and biltong. This increases the risk of human exposure to the pathogen," said Moerane.
To decrease contamination and the likelihood of a new outbreak of listeriosis, scientists advise the government and business sector to enact strict food safety regulations at abattoirs and processing facilities.
Among pregnant women, listeriosis is a potentially fatal illness that can result in miscarriage and stillbirth. The majority of human cases are linked to eating prepared foods, and the risk of disease rises with the quantity consumed. The refrigerated temperatures at which items are kept to avoid rotting allow the disease to live and grow.
