Risk assessmentindependent cross-checkfull text checked I-CHK-05 in-depth review
EFSA: controlling Campylobacter in broilers
Update and review of control options for Campylobacter in broilers at primary production.
Overview
EFSA BIOHAZ Panel. EFSA J 2020 · PMID 32874298 · DOI 10.2903/j.efsa.2020.6090
Farm measures could reduce human Campylobacter infections from chicken meat substantially.
Does the study support the specific claim? Partly · Methodological quality: high
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Effect of on-farm control options on human campylobacteriosis from broiler meat
- How was the study done?
EFSA scientific opinion (PAF modelling, expert knowledge elicitation)
- How many people, animals or samples were studied?
Not applicable; EU broiler production
- What was actually found?
In the EU, about 27% of broiler flocks and 37% of fresh broiler meat carry Campylobacter (2008 baseline: 71% of batches, 76% of carcasses); chicken meat may cause 20-30% of human cases. Farm measures could cut broiler-related cases by roughly 7-27% each (very uncertain); a 3-log cut in gut counts by 58%.
- How large was the observed effect?
PAF; EKE
- What do the results mean in everyday life?
The risk is real and can be reduced.
- What are the study's limitations?
Wide uncertainty
- What does it say about Elawady's specific claim?
Supports pathogen claim, not avoidance.
- Do the results apply to Germany and Europe?
Directly EU.
- What can explicitly not be concluded from this study?
Exact effect sizes; combined effects; anything about digestibility or gut damage from chicken meat.
Scientific in-depth review
1. Full reference
- Authors
- EFSA BIOHAZ Panel
- Journal
- EFSA J
- Year
- 2020
- Identifier
- PMID 32874298 DOI 10.2903/j.efsa.2020.6090
- Verification
- verified – PubMed efetch 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- full text
- Conflicts of interest and funding
EFSA opinion requested by the European Commission; produced under EFSA's declarations-of-interest framework (individual declarations not reproduced in the retrieved text).
2. Research question
Effect of on-farm control options on human campylobacteriosis from broiler meat
3. Study design and population
- Study design
- Risk assessment – EFSA BIOHAZ Panel scientific opinion (adopted 18 March 2020): literature review, population attributable fraction (PAF) calculations from risk-factor studies, updated QMRA-type model (caecal-skin regression + 8 consumer-phase models + dose-response), and Expert Knowledge Elicitation (adapted SHELF) for ranking
- Population
EU broiler production
- Country
EU
- Period
Literature since the 2011 opinion up to 2019/2020; opinion adopted 18 March 2020
- Sample size
Not applicable (evidence synthesis); e.g. 15 studies on caecal-skin concentration relationship; PAF from multiple risk-factor studies (half from Nordic countries)
- Inclusion and exclusion criteria
Literature on on-farm control options for Campylobacter in broilers; no systematic-review protocol with formal inclusion criteria reported in the retrieved text.
4. Methods and endpoints
- Exposure / intervention
On-farm control options
- Comparator
No intervention
- Endpoints
Relative risk reduction
- Statistical methods
PAF; EKE
5. Actual results
- Results
Context: Campylobacter is the most frequently reported foodborne pathogen in the EU (>200,000 confirmed cases/year; ~70% of confirmed zoonoses in 2016); EU reports show prevalence ~27.3% in broiler flocks and 36.7% in fresh broiler meat (2016); 2008 EU baseline: 71% of broiler batches colonised and 75.8% of carcasses contaminated (range between Member States 2.0-100% and 4.9-100%). Broiler meat handling/preparation/consumption may account for 20-30% of human cases and the chicken reservoir as a whole 50-80% (2010 EFSA estimate). Updated model: a 3-log10 reduction in caecal concentrations reduces EU risk attributable to broiler meat by 58% (previous opinion >90%). EKE medians (90% PI): vaccination 27% (4-74%); feed/water additives 24% (4-60%); discontinued thinning 18% (5-65%); few well-trained staff 16% (5-45%); avoiding drinkers with standing water 15% (4-53%); disinfectants in drinking water 14% (3-36%); hygienic anterooms 12% (3-50%); designated tools 7% (1-18%). Rodent control could lower flock prevalence by up to 19%. Combined effects cannot be quantified.
- Absolute risks
No absolute risk estimates; outputs are relative risk reductions of EU campylobacteriosis attributable to broiler meat.
- Authors' conclusion
Substantial but uncertain risk reductions.
6. Strengths
- Authoritative EU risk assessment updating the 2011 opinion with new data and models
- Explicit, structured uncertainty assessment (EKE with probability intervals)
- Multiple evidence streams and model alternatives compared
7. Weaknesses
- Wide, overlapping probability intervals make ranking uncertain
- Relies on risk-factor studies with Nordic over-representation and on an outdated 2008 baseline survey
- Expert judgement by working-group members themselves
- Effects of combined measures cannot be quantified
- Addresses on-farm control and human campylobacteriosis only; nothing on digestibility or gut effects of chicken meat
8. Risk of bias
- Orienting tool
- none (regulatory risk assessment/scientific opinion; no standard RoB tool applies)
- Type of assessment
- structured assessment based on the full text by a single reviewer (no formal double review)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Changed from not_assessable to a structured judgement (some_concerns); dimension bias_risk set to some_concerns accordingly. Single-reviewer structured judgement; a formal assessment would need two independent reviewers.
| Domain | Judgement | Rationale |
|---|---|---|
| Evidence identification | some concerns | Literature review updating 2011 opinion; no systematic search protocol reported in retrieved text. |
| Input data quality/representativeness | some concerns | Risk-factor studies over-represent Nordic countries; EU baseline from 2008. |
| Modelling | low | Model structure, alternatives and parameter uncertainty explicitly described. |
| Expert judgement | some concerns | Structured SHELF-based EKE, but experts were the working-group members who drafted the opinion. |
| Uncertainty communication | low | 90% probability intervals and limits of combined-effect estimation explicitly reported. |
Full-text review (25 October 2026): Added EU Campylobacter burden and prevalence figures (27.3% flocks, 36.7% meat; 2008 baseline 71%/75.8%), attribution 20-30%/50-80%, all EKE estimates, model update (58% vs >90%), limitations; bias not_assessable -> some_concerns; noted irrelevance to C-CHK-04.
9. Assessment of the statistical interpretation
Estimates are relative and model-based with large uncertainty; they show that broiler-associated campylobacteriosis is substantial and partly preventable, not exact effect sizes.
10. Relevance to the specific claim
Supports C-CHK-09 (broiler meat a major Campylobacter source). Not informative for C-CHK-04 (digestibility/gut damage of chicken breast), which it does not address.
11. Independent contrary findings
Not applicable.
12. Transferability to Germany and Europe
Directly EU.
13. Overall methodological judgement
Authoritative EU evidence that broiler chickens and broiler meat are a major source of human Campylobacter infection (high flock and carcass contamination in the EU) and that farm-level controls can reduce, but not eliminate, this risk. It does not address chicken digestibility or gut-microbiome damage.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | high |
| Risk of bias | some concerns |
| Precision of results | low |
| Directness | direct |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Effectiveness of combined interventions; current EU-wide prevalence (no baseline since 2008); applicability to Egyptian production.
15. Linked fact checks
- Chicken carries Campylobacter and Salmonella, which cause human infections. – Studies supporting the claim
- About 80-85% of chickens are contaminated with Salmonella, even with the cleanest slaughter methods (the blood is contaminated). – Studies with mixed or unclear results