Campylobacter jejuni is a Gram-negative, microaerophilic, thermophilic curved rod and the most frequently reported cause of bacterial gastroenteritis worldwide. The genus includes C. jejuni (accounting for approximately 90% of human infections) and C. coli (about 10%). Campylobacter requires reduced oxygen (3-6%) and elevated carbon dioxide (2-10%) for optimal growth and is thermophilic with an optimum growth temperature of 42°C, matching the avian gastrointestinal tract.

Campylobacteriosis is characterized by acute, self-limiting diarrhea (often bloody), abdominal cramps, fever, and nausea, with an incubation period of 2-5 days. Although most infections resolve within a week, severe complications include Guillain-Barré syndrome, an autoimmune polyneuropathy triggered by molecular mimicry between C. jejuni lipooligosaccharides and human gangliosides. The infectious dose is low, estimated at 500-800 cells. Major sources include undercooked poultry, raw milk, and untreated water. Handling of raw chicken is a significant risk factor in domestic kitchens.

Detection of Campylobacter requires microaerophilic incubation at 42°C for 48 hours on selective media such as modified charcoal cefoperazone deoxycholate agar (mCCDA) or Campy-CVA agar. Enrichment in Preston or Bolton broth improves recovery from processed foods. Confirmation involves Gram stain (gull-wing morphology), oxidase and catalase tests, and hippurate hydrolysis (C. jejuni positive, C. coli negative). Molecular methods include multiplex PCR targeting hipO (C. jejuni) and asp (C. coli), as well as real-time PCR and whole-genome sequencing for subtyping in outbreak investigations.

Control of Campylobacter in poultry production is challenging due to high levels of intestinal carriage. Interventions include biosecurity measures at the farm level (barrier hygiene, control of insects and rodents), bacteriophage therapy, competitive exclusion cultures, and the use of feed additives. At the consumer level, thorough cooking (74°C internal temperature) and prevention of cross-contamination between raw poultry and ready-to-eat foods are essential. Freezing of poultry carcasses reduces Campylobacter counts by 1-2 log units. Campylobacter is frequently found alongside Salmonella and E. coli in poultry production. It causes food infection rather than intoxication, with symptoms appearing 2-5 days after ingestion.