Environmental Health visited the Hartbeespoort poultry abattoir and collected food and environmental samples which tested positive for Listeria monocytogenes.
Department of Health samples were submitted to the National Health Services Laboratory (NHSL) in Parktown at the Charlotte Maxeke Infection Control Laboratory.
Duplicate samples taken by Sovereign Foods went for independent analysis by Deltamune – a SANAS accredited facility approved to test for Listeria in food and hygiene samples.
Sovereign Foods said Deltamune found no Listeria in samples but the NHSL lab found eight of 14 were positive.
The abattoir was served with a prohibition notice pending further investigations on 22 December. This was removed on 8 January and operations have resumed.
Sovereign Foods had called the notice ‘premature and unfounded’ and started legal action.
Blaine van Rensburg, head of production, said: “Public health officials have not isolated Listeria bacterium in the latest samples of our plant, and as a result they are willing to lift the prohibition notice.”
Elusive ST6 isolates
Whole genome sequencing (WGS) of 337 isolates from January 2017 includes clinical, food and food production environment isolates.
Clinical isolates are represented by nine sequence types (ST): ST1, ST101, ST2, ST219, ST5, ST54, ST6, ST8 and ST876. However, 91% (225/247) are ST6 and are closely related, representing a single strain of L. monocytogenes.
The ST6 strain was identified in isolates from all nine provinces and supports the hypothesis of a single source of food contamination such as a widely consumed product or multiple items produced at a single facility, said authorities.
World Health Organization
Dr Rufaro Chatora, country representative from the World Health Organization, said it and the international community are ready to support the Department of Health and others involved in fighting the outbreak.
“The Government of South Africa shared the detailed information with WHO in compliance with the provisions of the international health regulations. This has helped South Africa and the global community at large to protect health, to stand ready to identify, to respond and to control outbreaks where they occur in keeping with the regulations.
“The country has also implemented some important measures such as making Listeriosis a notifiable condition for the first time ever. This is helping to track the diseases.”
Dr Aaron Motsoaledi, South African minister of health, said it cannot yet link clinical isolates from patients to a particular foodstuff or production environment.
“All the samples collected from the food and environment at the abattoir have so far failed to pick up the outbreak strain ST6,” he said.
“But we can conclude that it has Listeria, which can cause illness, and hence it was in the best interest of public health that the abattoir was prohibited from further preparing food pending the cleaning of the environment and meeting certain conditions given to them.”
Dr Motsoaledi said the abattoir was closed two months ago by the Department of Agriculture, Forestry and Fishery (DAFF) following findings of unhygienic conditions and practices not related to Listeria.
“These were preceded by Environmental Health investigations which were conducted earlier in July 2017 by Tshwane Metropolitan Municipality the findings of which were existence of conditions that constitute a nuisance in the facility.
“These led to delayed issuance of Certificate of Acceptability at the time until such time that the corrective measures were implemented.”
More carcass washing points
Van Rensburg said the company was strengthening steps to ensure product safety such as installation of five more carcass washing points.
Other plants typically have washing of carcasses at one point and also prior to chilling.
“It is important to note that South African law does not stipulate how, how often or with what you are required to wash the carcass,” he said.
“Typically, you would expect to see a carcass washer after defeathering and in the evisceration line as a part of the process. Additional points would generally be considered above requirements.
“All these points are or will be proportionally dosed with alternating anti-microbial agents at optimal concentration in order to ensure microbial reduction.
“These anti-microbial agents are specifically selected for their oxidative reduction potential (ORP) and residual action which further mitigates potential cross contamination of the carcass during handling during portioning, trimming and packing.”
The South African Poultry Association (SAPA) said it has contacted DAFF and the DOH to determine a sample and test protocol using agreed and accredited labs to produce credible and repeatable results.
It added testing should be stepped up on locally produced and imported frozen chicken that is thawed, handled, sold as ‘loose serve’ and also when re-packed locally.
Since December, the Department of Health has added Listeriosis to the list of notifiable diseases.
Industry has been requested to submit details of Listeria-positive food items, environmental swabs and isolates to the National Institute for Communicable Diseases (NICD) and whilst several stakeholders have done this not all have yet responded, said authorities.