Discovery of a veterinary drug in ham that was served as part of a public high school meal has ignited a government probe on Wednesday.

According to local news reports, the foreign substance -- later confirmed as Aluspray, a veterinary spray used to stop bleeding in livestock and not meant for human ingestion -- was discovered in ham at a high school in Chuncheon, Gangwon Province.

According to the school, the substance was found by the school’s nutritionist. The ham was produced by a well-known company that distributes processed meat nationwide, and was found to have been processed at a plant in Gimje, North Jeolla Province. An internal review by the distributor concluded that ham from the same batch was also delivered to an elementary school.

The names of the schools and the company have not been disclosed.

The manufacturer sent an apology to the school, while strengthening the screening process for foreign substances in raw meat and banning the use of the drug to its raw meat supplier.

But the school principal judged the measures as inadequate, demanding further strengthened actions.

“We are conducting a two-month full investigation into which schools the ham with foreign substances was delivered to, and will collect the products as soon as we confirm this information. Also, the product of the corresponding brand will be suspended for one month in accordance with the regulations,” an official with the supply center, which delivered the ham to the high school, was quoted as saying by local media outlets.