South Africa’s public health officers say there is unequivocal evidence that polony from a Tiger Brands plant is to blame for the world’s largest ever Listeria outbreak, stopping just short of accusing some elected officials of spinning propaganda in the company’s favor.
A statement Tuesday from South Africa’s National Institute for Communicable Diseases (NICD) did not mince words on the source of the outbreak, which includes 982 laboratory-confirmed listeriosis cases and 189 deaths. The NICD reported test results Tuesday that showed samples of finished product returned seven positives for the outbreak strain of the foodborne pathogen.
“This means that the outbreak strain has been found inside the ready-to-eat processed meat products manufactured at Enterprise Foods’ Polokwane production facility, dispelling claims made to the contrary,” according to the report from the federal agency.
The NICD also reiterated details about multiple swab samples from the Enterprise Foods processed meat plant that already tested positive for outbreak strain of Listeria monocytogenes sequence type 6 (ST6).
In refuting statements issued this past week by South Africa’s Democratic Alliance party, the federal public health agency referred to whole genome sequencing tests. The NICD did not name the political party or Patricia Kopane, the Member of Parliament who was quoted in the party’s statement.
Instead, the NICD offered hard science to rebut the party statement. The agency described whole genome sequencing tests as the “gold standard,” comparing them to paternity testing for people.
“The L. monocytogenes genome has approximately 3 million base pairs. The outbreak strain isolates from patients and from the Enterprise Foods’ Polokwane production facility — notably, the post-cooking area and the final product clips and casing — differ by (less than or equal to) only 7 single base pairs out of 3 million,” the NICD reported Tuesday.
“This extremely high level of genetic relatedness, 99.99 percent similarity, means there can be no doubt that these L. monocytogenes ST6 strains are all linked, and that there is certainty that products manufactured at Enterprise Polokwane are the source of the outbreak.”
The NICD expressed concern “about the confusion that emanated from statements” during a meeting called by the Parliamentary Portfolio Committee on Agriculture on March 28. The agency did not call out Tiger Brands, even though the company has suggested the products of its wholly-owned subsidiary are not the source of the Listeria.
Of major concern for NICD are statements that the primary source of the outbreak is still unknown. The public health agency flatly disagrees with that claim.
“From the evidence above, it is extremely misleading for anyone to claim that the primary cause of this listeriosis outbreak is unknown,” according to NICD’s investigation update Tuesday.
“Furthermore, we condemn the statement made that the government prematurely scapegoated ‘Enterprise and Rainbow’ without sufficient evidence. We contend that this evidence has been amply provided by the NICD.
“We do not regard these claims as a small matter, because the NICD is not just a routine diagnostic laboratory with an impact localized to South Africa. The NICD’s work goes far beyond the borders of our country and has an international impact.”
Further defending the integrity of its investigation and testing practices, the NICD cited its previous and ongoing collaboration with the World Health Organization, the U.S. Centers for Disease Control and Prevention, the U.S. National Institutes of Health, the European Centre for Disease Control and Public Health England.
The NICD is the coordinator of the PulseNet Africa network, within PulseNet International. PulseNet is a global network of laboratories dedicated to tracking foodborne infections worldwide, all of whose laboratories, including the NICD, utilize internationally recognized, standardized genotyping methods and share information in real-time.
Weighing in with support for the NICD’s statement Tuesday, attorneys representing outbreak victims and their families praised the agency.
“The offices of Richard Spoor Inc. supports the NICD for condemning those claiming that the source of the outbreak is unknown,” according to a news release from the law firm in South Africa.
“The ST6 strain of Listeria responsible for the outbreak was not just found in the environment of the Enterprise Foods Polokwane operations as some commentators suggest, but also on the final product.”
Editor’s note: The offices of Richard Spoor is pursing the class action lawsuit in partnership with the Seattle law firm Marler Clark LLP. Bill Marler, a founding member of the firm, is publisher of Food Safety News.
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