BELGRADE, April 21 (Xinhua) -- The number of people apparently poisoned at a local fast food restaurant in the northern Bosnian city of Tuzla reached 131 Monday, said reports reaching here from Bosnia.
The food poisoning victims sought help at the city's infectious diseases clinic complaining of severe stomach pain, nausea and other difficulties, the Bosnian Fena news agency reported, citing information from Tuzla University Clinical Center.
Four of those hospitalized are in a serious condition although their illness is not life-threatening, hospital sources confirmed.
All the patients had dined at the popular Bos Burger fast food restaurant in downtown Tuzla. Local media said scores of people had come down with stomach problems since Friday.
The restaurant has been closed as hospital officials investigate the source of the poisoning.
The results of food analysis are expected to determine the cause of poisoning, but some media reports suggested that bad mayonnaise in hamburgers and sandwiches had caused the problem.