More than 700 employees at an Airbus Atlantic plant in northwest France fell ill after the Christmas meal that the company offered on December 14, regional health authorities indicated this Friday.

The affected workers, employed at a plant located in the town of Montoir-de-Bretagne, showed “clinical symptoms of vomiting or diarrhea, the majority on December 15 and 16,” indicated the Regional Health Agency.

The agency opened an investigation in collaboration with different French public health services and the department “to find out the origin of this food infection and take appropriate prevention measures,” the institution informed AFP.

The investigations “focus on the festive food on December 14,” the agency said.