Listeria contaminated abattoir to remain closed
“At this juncture, we cannot conclude that the abattoir called Sovereign Foods is the source of the present outbreak. [However] 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.
“What concerns us more at this moment is that this particular abattoir was closed two months ago by DAFF (Department of Agriculture, Forestry and Fisheries) following the discovery of unhygienic conditions and practices, which of course were not necessarily related to Listeria,” said the minister
The Department of Health has put the Listeriosis outbreak on high surveillance as 119 new cases have occurred since 5 December 2017 and 61 patients have died.
Sovereign Foods abattoir, which lab tests found to contain traces of Listeria, did not test positive for ST6, which is the strain suspected to be the cause of the present outbreak.
Motsoaledi said environmental health investigations had been conducted in July 2017 by Tshwane Metropolitan Municipality at the abattoir, the findings of which were “existence of conditions that constitute a nuisance in the facility”.
“These led to delayed issuance of a Certificate of Acceptability at the time until such time that the corrective measures were implemented,” said the minister.
Sovereign Foods
Sovereign Foods was served with a prohibition notice after a chicken sample that was traced to its abattoir from a Listeriosis patient’s home tested positive for listeria.
According to the Department of Health, the chicken sample from the fridge at the patient’s home tested positive for Listeria monocytogenes.
“This chicken was traced back to the store, and from there traced back to the abattoir it was sourced from, Sovereign Foods.
“Environmental health practitioners visited the abattoir and collected food and environmental samples, several of which tested positive for Listeria monocytogenes. As a precaution, the abattoir was served with a prohibition notice pending further investigations,” Motsoaledi said.
Genome sequencing
In an effort to scientifically trace the origins of the outbreak, a whole genome sequencing (WGS) analysis was done.
WGS is a DNA-fingerprinting analysis which aims to determine whether particular organisms are related and are of the same sequence type.
To do this, the National Institute for Communicable Diseases (NICD) used what it calls isolates from three different sources. These sources are:
- Clinical isolates: obtained from the blood of a sick patient;
- Food isolates: obtained from the food that is found in the patient’s home or any other locality like food production sites; and
- Environmental isolates: obtained from the environment where food is produced.
The clinical isolates are represented by nine sequence types which are ST1, ST101, ST2, ST219, ST5, ST54, ST6, ST8 and ST876. However, 91% of these clinical isolates are sequence type 6 (ST6), which are closely related and represent a single strain of Listeria monocytogenes.
“It can then be said that the strain for this present outbreak we are experiencing is ST6 or strain 6. It has been identified in isolates from all nine provinces. This supports the current working hypothesis that a single widely consumed food product or multiple food products produced at a single facility is causing the outbreak,” said Motsoaledi.
He said although inroads have been made, they cannot yet link the clinical isolates obtained from patients to a particular food stuff or a particular food production site environment.
Sovereign Foods abattoir, which contained traces of Listeria, did not test positive for the ST6, which is the strain suspected to be the cause of the present outbreak.
“All the samples collected from the food and environment at the abattoir have up to so far failed to pick up the outbreak strain ST6,” he explained
The abattoir was nonetheless slapped with a prohibition notice for public health safety because other strains with the potential to cause disease were identified.
Health calls for clean-up of food industry
In an effort to curb the outbreak, a special meeting was held with all senior managers in Gauteng on 15 December 2017 to inspect all food premises within the province, targeting food processing areas and retail foods.
“The director general of the National Department of Health has formally requested food industry stakeholders to submit details of Listeria-positive food items, environmental swabs and Listeria isolates to the NICD,” said the department.
Despite several stakeholders coming forward, the ministry said not all stakeholders have responded as yet.
Useful sources
The Department of Health has urged pregnant women to register on MomConnect to receive updates on Listeriosis as babies under 28 days old are the worst affected.
“Clinical Listeriosis management guidelines are available on the website and the NICD continues to operate its 24-hour hotline to support healthcare workers,” the minister said.
Members of the public can call the NICD Emergency Operations Centre during working hours on 011 386 2000. Health workers can call the NICD Hotline for Clinical Emergencies after hours on 082 883 9920.
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