Frozen corn and possibly other frozen vegetables are the likely source of an outbreak of Listeria monocytogenes that has been affecting Austria, Denmark, Finland, Sweden, and the United Kingdom since 2015.

Experts used whole genome sequencing to identify the food source, which initially was thought to be limited to frozen corn. As of 8 June 2018, 47 cases including nine deaths had been reported.

The same strains of L. monocytogenes have been detected in frozen vegetables produced by the same Hungarian company in 2016, 2017 and 2018. This suggests that the strains have persisted in the processing plant despite the cleaning and disinfection procedures that were carried out.

The available information confirms the contamination at the Hungarian plant. However, further investigations, including thorough sampling and testing, are needed to identify the exact points of environmental contamination at the Hungarian plant. The same recommendation applies to other companies belonging to the same commercial group if environmental contamination is detected.

On 29 June 2018, the Hungarian Food Chain Safety Office banned the marketing of all frozen vegetable and frozen mixed vegetable products produced by the affected plant between August 2016 and June 2018, and ordered their immediate withdrawal and recall. This last measure is likely to significantly reduce the risk of human infections and contain the outbreak. All freezing activity at the plant has been stopped.

New cases could still emerge due to the long incubation period of listeriosis (up to 70 days); the long shelf-life of frozen corn products; and the consumption of frozen corn bought before the recalls and eaten without being cooked properly.

To reduce the risk of infection, consumers should thoroughly cook non ready-to-eat frozen vegetables, even though these products are commonly consumed without cooking (e.g. in salads and smoothies). This applies especially to consumers at highest risk of contracting listeriosis – such as the elderly, pregnant women, newborns and adults with weakened immune systems.

• Multi-country outbreak of Listeria monocytogenes – first update

Frozen broccoli contaminated with Listeria monocytogenes bacteria has been found at Stop & Shop’s store on Ellington Road in South Windsor, and the chain is recalling the product. State food inspectors found the listeria-tainted, 16-ounce “Private Brands Frozen Broccoli Cuts” during a routine test of sample products at the store and the supermarket chain issued the recall on Monday. The product code for this broccoli is “UPC 068826700926” and the packages’ use-by code is “BEST BY MAR 15 2020.” Stop & Shop issued a voluntary recall on the frozen broccoli based on the results of tests done by the state Department of Consumer Protection.

Giant Food Stores, with locations across Maryland, said Wednesday it is voluntarily recalling frozen broccoli under its own label because it may have been contaminated with the Listeria monocytogenes bacteria. Private Brand Frozen Broccoli Cuts (16 oz.) with a sell-by date of March 15, 2020 and UPC code 68826700926 are being recalled by the grocery chain after a supplier notified the company of the possible contamination. Giant/Martin’s has removed all affected product from its shelves and urges customers to return the product to their local store for a full refund, according to a news release. While there have been no reports of illnesses to date, the frozen vegetable product is being recalled as a precautionary measure after a product sampled by the state of Connecticut Department of Consumer Protection tested positive for Listeria monocytogenes.

Listeria Monocytogenes is an organism that can cause serious and sometimes fatal infections in young children, frail or elderly people and others with weakened immune systems. It’s also particularly dangerous to pregnant women, as it can cause miscarriages and still births. Healthy people usually only suffer short-term symptoms, such as high fever, severe headache, stiffness, nausea, abdominal pain and diarrhea. Anyone who has these symptoms are urged to seek medical attention.

According to press reports, the listeriosis epidemic is under control now that meat products from Enterprise and Rainbow Chicken have been recalled, Health Minister Aaron Motsoaledi told Parliament on Tuesday. “Since the recall, we have had fewer than five cases a week in the past five weeks compared to 40 a week before the recall,” Motsoaledi said during his R205bn Budget Vote in Parliament.

According to the NICD report released today, 1,033 laboratory confirmed cases (728 ill, 204 dead) have been reported from 01 January 2017 to 10 May 2018. The number of reported cases has decreased since the implicated products were recalled on 04 March 2018.

Neonates ≤28 days of age are the most affected age group, followed by adults aged 15 – 49 years of age.

Most cases have been reported from Gauteng Province (59%, 605/1 033), followed by Western Cape (13%, 130/1 033) and KwaZulu-Natal (7%, 75/1 033) provinces.

The findings of the NICD are in summary:

• 92% of clinical isolates taken from case-patients belong to listeria sequence type 6 (ST6) and are genetically similar confirming that a single strain of listeria is responsible for the outbreak
• 86% of patients interviewed reported eating polony in the month before falling ill with listeriosis
• The isolates taken from patients and from the Enterprise Foods’ Polokwane production facility (the post-cooking area and final production clips and casing) are 99.99% similar, linking the L. monocytogenes ST6 strains
• 7 samples of ready-to-eat processed meat products taken at the Enterprise Factory in Polokwane on February 15, 2018 tested positive for the ST6 outbreak strain. The samples were taken by the NICD accompanied by two WHO food safety experts.

According to the NICD, these findings are irrefutable evidence that:

• Enterprise Foods and by extension Tiger Brands Limited are the source of the listeria outbreak.
• 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. NICD Press Statement.

To Tiger Brands’ credit, it has been transparent with its test results.  Its transparency support of the NICD findings is hopeful for its customers that suffered as a result of the Listeria-tainted product.  Tiger Brands should be commended for its willingness to provide the results in a public forum.

Here is the Tiger Brands’ announcement in full:

Results of Independent Tests carried out in respect of the presence of Listeria monocytogenes ST6 type (“LST6”) Shareholders are referred to the SENS announcement issued by the Company on 5 March 2018, relating to an order issued by the National Consumer Commission for the Company to conduct a recall of certain identified Enterprise products. In that announcement, it was stated that in a batch of one of its products tested by the Company on 14 February 2018, the presence of the ST6 strain could not be confirmed and that the relevant samples had been sent to an external laboratory for the identification of the strain. The test results were received on 15 March 2018, but these had proved inconclusive and, as a result, the samples were sent for further re-testing.

The purpose of this announcement is to update shareholders on the results of the independent laboratory re-testing which was carried out in respect of the presence of LST6 in the above samples which were manufactured at the Enterprise Polokwane processing facility. On 24 April 2018, Tiger Brands received confirmation of the presence of LST6 in these samples. As reported previously, we have been actively engaging with the Department of Health and the National Institute of Communicable Diseases on our findings and will continue to collaborate with them on the actions taken to date to actively address our findings.

The Enterprise facilities in Polokwane, Pretoria and Germiston still remain closed while remedial work continues. An arrangement has been concluded between Pork Packers (which is based in Clayville) and our pig suppliers to contract slaughter on their behalf with effect from 2 May 2018.

“Now it is time to take care of the victims and to work with government, the industry and the public to see that an outbreak like this never, ever occurs again,” said, US Food Safety Attorney, William Marler, who is acting as a consultant to the South Africa Listeria Class Action.