Coloured scanning electron micrograph (SEM) of Salmonella enterica subsp. enterica serovar Typhimurium bacteria. This flagellated Gram-negative bacterium is a major cause of food poisoning (salmonellosis) in humans, most commonly caught from infected pork, poultry and eggs. Symptoms include fever, chills, severe diarrhoea and vomiting. Treatment is with antibiotics. Magnification: x12,000 when printed at 15cm wide.