Campylobacter is a gram-negative, microaerophilic genus of bacteria of the family Campylobacteriacae. There are more than 20 species of Campylobacter, not all of which cause human illness. Approximately 90% of human Campylobacter illness is caused by one species, Campylobacter jejuni. Less common species, such as C. coli, C. upsaliensis, C. fetus, and C. lari, can also infect people.
Campylobacter jejuni grows best at 37°C to 42°C and seems to be well-adapted to birds, which have an approximate body temperature of 41°C to 42°C and can carry the bacteria without becoming ill.
These bacteria are fragile. They cannot tolerate drying. Freezing reduces the number of Campylobacter bacteria on raw meat.