The prosecution has appealed a court's ruling that gave suspended prison terms to three employees of a supplier that had distributed contaminated burger patties to McDonald's Korea, judicial sources said Monday.

On Tuesday, the Seoul Central District Court sentenced an executive and a factory manager of the burger patty supplier to three years in prison, suspended for four years, on charges of distributing 63 tons of contaminated food.

The investigation showed that the patties tested positive for intestinal hemorrhagic E. coli contamination, which causes the hemolytic uremic syndrome, also known as the hamburger disease.

The other quality control manager was sentenced to two years in prison, also suspended for four years, on the same charge.

According to the sources, the prosecution appealed the ruling Friday.

In July 2017, the mother of a 5-year-old girl filed a complaint against McDonald's Korea, claiming that her daughter was diagnosed with the hamburger disease after eating a burger served with an undercooked patty the previous year.

In February 2018, prosecutors indicted the supplier employees for violating hygiene control and food safety regulations. But they dropped charges against the fast food chain, citing insufficient evidence to back the accusations.

The prosecution launched a re-investigation into the case the following year, after nine civic groups filed a new complaint against McDonald's Korea, claiming that it is responsible for the past selling of unhealthy burgers.

The former and current executives of the food chain have recently been questioned by prosecutors on whether they pressured their employees to make false statements during the initial investigation in order to hide the company's alleged knowledge of the distribution of contaminated burger patties, according to the sources. (Yonhap)