Swiss authorities are investigating if cheese from one company is linked to the deaths of 10 people with listeriosis since 2018.

The Schwyz Public Prosecutor’s Office has opened criminal proceedings in connection with Listeria in dairy products and is investigating allegations against the owner of the cheese firm.

A total of 34 cases are believed to have been infected with the same Listeria strain that was detected in brie from the dairy, according to the criminal complaint. Ten of the 34 sick people died. This resulted from analyzes commissioned by the federal government.

The ongoing investigation, with Schwyz police, includes whether the business owner is responsible for the illnesses and has violated food law.

Käserei Vogel AG, based in Steinerberg, a municipality of Schwyz, found Listeria in semi-hard cheese and at its production site in May this year. The company issued a recall, told authorities and informed its buyers to remove the products from shelves. The cheesemaker has already closed the business. More than 25 items sold across Switzerland were recalled and distribution also included Belgium and Germany.

Listeria outbreak link
In that same month, officials from the Federal Food Safety and Veterinary Office (FSVO) told Food Safety News at least 11 people had been infected by Listeria with two deaths and analysis was pending for a further 10 infections to see if they belonged to the outbreak cluster.

Of the 11 confirmed cases, five were men and six were women aged 66 to 86 years old. Infections occurred in seven cantons, or regions, of the country. Cheese was made from pasteurized milk.

The Center Hospitalier du Valais Romand (CHVR) previously said that from late March to early May four patients were diagnosed with invasive listeriosis. Infected patients did consume cheese during hospitalization but the brand was not clear. Three people recovered but one person with underlying health conditions died.

Symptoms of infection can include vomiting, nausea, persistent fever, muscle aches, severe headache and neck stiffness. It can take up to 70 days after exposure to Listeria for symptoms of listeriosis to develop.

Pregnant women, the elderly, young children, and people such as cancer patients who have weakened immune systems are particularly at risk of serious illnesses, life-threatening infections and other complications.