ⓒYONHAP News

Authorities looking into the mass food poisoning at a kindergarten in Ansan, Gyeonggi Province will expand their investigation to focus on the school's learning program.

Officials have yet to find any trace of the enterohemorrhagic E. coli bacteria in the food the children ate or the facilities at the school.

A local health center in Ansan said they are now looking into all possible sources, including what the children were learning. One official noted that if the children had a class when they drank water or touched mud, this could have exposed them to E. coli as well.

Over a hundred students at the kindergarten are believed to be showing symptoms of food poisoning since the first case on June 12.

Fifteen students are now displaying signs of hemolytic uremic syndrome (HUS), also known as hamburger disease, with four undergoing dialytic therapy due to worsened kidney conditions.

A total of 24 patients have been hospitalized, including family members.

On Friday, the Education Ministry issued a public apology over the case, expressing regret for causing additional concerns over children’s health and safety amid the protracted COVID-19 crisis.

The ministry also apologized to the affected children and promised to strengthen the country's preventive healthcare system.