Four Buenos Aires McDonald’s outlets were closed yesterday after testing revealed the presence of the toxic “escherichia coli” bacteria in the company’s hamburgers and chicken sandwiches.

Samples were taken from the menu by health authorities after a McDonald’s customer complained of food poisoning a month ago.

The toxic bacteria can cause “hemorrhagic colitis, uremic hemolitic syndrome and death” according to Martha Lopez Barrios, the director of Hygiene and Food Safety for Buenos Aires. It “comes from the digestive tracts of animals, contaminating their meat”, she explained.