An outbreak of listeriosis (a disease caused by Listeria monocytogenes) linked to frozen corn and possibly to other frozen vegetables, has been ongoing in five European Union Member States (Austria, Denmark, Finland, Sweden and the United Kingdom) since 2015. The European Centre for Disease Prevention and Control (ECDC) reports that as of 15 June 2018, 47 cases with nine deaths have been identified. Whole-genome sequencing (WGS) analysis has shown that the human cases are linked to frozen corn and several other frozen vegetable products produced at the Greenyard Factory in Hungary. The outbreak strain is L. monocytogenes sequence type 6 (ST6), but this strain is NOT related to the ST6 strain which caused the recent listeriosis outbreak in South Africa; NICD scientists have confirmed this with ECDC colleagues.
Woolworths has announced a recall of their frozen savoury rice product as a precautionary measure; the product contains frozen corn and is reportedly sourced from Belgium. This follows on an alert issued by the Hungarian Food Safety Agency to the global food industry. On 29 June 2018, the Hungarian Food Chain Safety Office banned the marketing of all frozen vegetables and frozen mixed vegetables produced by the company between August 2016 and June 2018 and ordered their immediate withdrawal and recall. All freezing activity at the plant was stopped in June 2018.
The ECDC advises that to reduce the risk of L. monocytogenes infection due to frozen vegetables, consumers should thoroughly cook frozen vegetables that are not labelled as ready-to-eat, even those that are sometimes consumed without cooking, for example in salads and smoothies.
We encourage all persons at high risk for listeriosis to cook frozen vegetables before eating (cook thoroughly in boiling water or heat to high temperatures (≥70°C)).
People at high risk for listeriosis include:
∙ pregnant women
∙ very young infants
∙ persons >65 years of age, and
∙ anyone with a weakened immune system (due to HIV infection, cancer, diabetes, kidney disease, liver disease, people with transplants and those on immunosuppressive therapy such as oral corticosteroids, chemotherapy, or anti-TNF therapy for auto-immune disease).