Campylobacter jejuni: Profile, Poultry Risk & Control

Campylobacter jejuni

It’s the most common bacterial cause of foodborne gastroenteritis in much of the world — and most cases trace to one food: chicken. Campylobacter jejuni is a fragile organism in the lab and a formidable one in the kitchen, where a few drops of raw chicken juice do the damage.

Taxonomy & characteristics

• Campylobacter jejuni (family Campylobacteraceae); Gram-negative curved rod, microaerophilic — needs reduced oxygen (it won’t grow in normal air or without any oxygen).
• Growth limits (approx): temperature ~30–45°C (thermophilic — doesn’t grow below ~30°C, which is why it doesn’t multiply on chilled chicken, only survives); pH ~4.9–9.5; aw ≥ ~0.98 — sensitive to drying, freezing reduces numbers.
• Doesn’t grow at refrigeration temperatures and dies readily with cooking — yet causes enormous illness because cross-contamination bypasses all of that.
• Complications include Guillain-Barré syndrome (autoimmune paralysis) in a small fraction of cases.

Sources & high-risk foods

• Reservoir: poultry intestines (chickens carry it harmlessly at high levels), cattle, sheep, wild birds; contaminated water.
• High-risk: raw/undercooked poultry, unpasteurized milk, contaminated water. Most infections are sporadic — the cutting board, not the outbreak.

Control measures

• Farm/slaughter: biosecurity, hygienic slaughter, carcass chilling and decontamination treatments.
• Kitchen (where most prevention happens): no washing raw poultry, separate boards/knives, handwashing, thorough cooking.
• Industry: process hygiene criteria (EU), freezing or crust-freezing to reduce loads on carcasses.

The chicken-washing myth

Washing raw chicken under the tap is one of the most persistent bad habits in home kitchens — and it does nothing but spray Campylobacter-laden droplets across the sink and counters. Food safety agencies have campaigned against it for years with limited success, because the habit feels like hygiene. The science is unambiguous: washing doesn’t remove meaningful bacterial loads, but it does aerosolize them. Cooking is the kill step; separation is the cross-contamination control. For industry, the parallel lesson is about process design: interventions that feel reassuring but spread contamination (looking at you, certain carcass washes without validated efficacy) deserve the same skepticism.