The city of Jyväskylä confirmed on Wednesday that there are 442 people affected by the salmonella outbreak that began a week ago and affects children and staff of local public and private daycare centers.
Of those infected, 377 are children and 65 are adults, the city authorities said in a statement.
Jyväskylä city authorities are investigating the outbreak, which began abruptly last week when some 150 children of daycare age had to go to hospital suffering from diarrhea and other severe stomach symptoms.
On Tuesday, only a few new cases more were reported, leading authorities to believe that the epidemic could be subsiding. Meanwhile, the cleaning work of the nurseries and facilities used by those affected has intensified.
The authorities have already received the preliminary results of the laboratory tests taken from the food served in the nurseries.
According to the first results, salmonella has been detected in fresh vegetables served for lunch on 18 June.
Swedish iceberg lettuce
Food suspected of causing the outbreak included "foreign iceberg lettuce, domestic fresh cucumber and domestic frozen peas," says the City of Jyväskylä.
According to experts, at this stage "it is not possible to say with certainty which vegetable the salmonella bacterium has come with, but the most likely cause of infection is iceberg lettuce."
The City of Jyväskylä says the foreign lettuce comes from a Swedish manufacturer. It arrived in the central kitchen ready for use and was not processed. Therefore, they believe that the possible contamination occurred during its production or at the Swedish facility where it was processed and bagged.
The domestic fresh cumber was washed and sliced in the central kitchen. Salmonella was not found in this product. Nor in the frozen pea, whose handling in the kitchen is very limited.
"It is assumed that the salmonella bacterium has come with the ready-to-use iceberg lettuce," the city says.
The samples will be retested for confirmation. In the meantime, it has been decided not to use foreign lettuce in meals for the time being.