The largest ever detected Listeria outbreak in known history is over, according to officials in South Africa.
Between Jan. 1, 2017, and July 17, 2018, South Africa recorded 1,060 laboratory-confirmed cases of listeriosis, including 216 deaths.
The outbreak was linked to a ready-to-eat (RTE) processed meat plant owned by Tiger Brands, the Enterprise Foods production facility in Polokwane. However, investigators for the government and in the private sector have not been able to determine how the outbreak strain was introduced in the affected factory.
A total of 12 million South African rand ($810,000) was spent to deal with the outbreak.
Health Minister Aaron Motsoaledi gave processed meats the all clear at a media briefing on Monday.
“A team of World Health Organization, international and local experts (have) agreed that because no cases of listeriosis due to the outbreak strain have been identified since the first week of June 2018, and that over the last two months the incidence rate of laboratory-confirmed listeriosis cases has dropped to pre-outbreak levels, the outbreak of listeriosis is over,” Motsoaledi said
Listeriosis cases have been recorded for 40 years in South Africa. There have been between 60 and 80 cases every year for the past five years.
In December 2017, South African authorities announced the outbreak and made listeriosis a notifiable medical condition. In March this year the Listeria was traced to a ready-to-eat sausage product known as polony made by Enterprise Foods.
The Listeria outbreak strain sequence type 6 (ST6) was identified in patient isolates, in the polony, and the processing environment of Enterprise Foods. However, about 10 percent of outbreak victims were infected with one of at least 19 different strains of Listeria.
The Enterprise factory in Polokwane is not open for production. Details on its status are expected next month. Enterprise Foods exported products to 15 countries in the African region but no linked cases were reported.
Neonates, infants 28 days or younger, were the most affected age group at 42 percent, or 443 of the 1,060 patients.
Almost 900 environmental health practitioners from every health district in South Africa have been retrained in factory inspections, food safety systems, and testing of factories for Listeria.
More than 150 facilities that produce RTE meat have been inspected with food and environmental testing conducted for Listeria.
Officials said 5,812 tons of affected foods have been recalled and destroyed since March. They expect the process will be completed by the end of September.
Following the outbreak, the Department of Health put in place a surveillance system, with support from the World Health Organization, to find and test all Listeria isolates from human cases to identify clusters of cases that may represent outbreaks. Early investigation should detect outbreaks faster and identify affected foods quicker.
Food safety laws have also been updated so all factories that make RTE processed meat and chicken need to have food safety management systems in place, according to a regulation published in June while inspections of plants are ongoing according to updated hygiene regulations.
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