False colour scanning electron micrograph (SEM) of a colony of Salmonella typhimurium growing on blood agar, showing individual & dividing flagellate, Gram- negative bacilli. S. typhimurium is a major cause of food poisoning (salmonellosis) in humans. Salmonella bacteria are transmitted in food. Infections are common in poultry & eggs. Inadequately cooked pork & beef are also potential sources. Oysters farmed near sewage outlets may become contaminated with faecal bacteria. Rats & mice are also common carriers. Clinical symptoms are headache, fever, abdominal pain & diarrhoea. Magnification: x2,300 at 35mm size. Yellow tinted version of B220/297