Caption

Salmonella. Coloured transmission electron micro- graph (TEM) of a single Salmonella enteritidis bacterium. The outer membrane and cell contents are seen; hair-like flagellae are visible (top). These Gram-negative rod-shaped bacilli cause food poisoning (Salmonellosis) in humans. Salmonella enteritidis produces enterotoxins which act on the small intestine. Infection occurs when numbers of these bacteria are ingested in contaminated food, particularly meat, milk and chicken eggs. Salmonella food poisoning symptoms include nausea, vomiting, abdominal pain and diarrhoea. The infection is usually controllable and rarely fatal. Magnification: x21,000 at 6x4.5cm size.