False colour scanning electron micrograph of the rod- shaped bacteria Salmonella enteritidis covering the surface of a kitchen cutting board. S. enteritidis was the cause of a severe outbreak of food poisoning in Britain in 1988. The outbreak was traced to chicken eggs containing the bacteria. Chickens have always been associated with Salmonella, but until recently it has been the less virulent species S. typhimurium. Magnification: x900 at 35mm size. Yellow tint.