Outbreak reportindependent cross-checkfull text checked★ key study I-LEG-118 in-depth review
Kidney-bean lectin outbreak in a French canteen
From Foodborne Disease Outbreak (FBDO) to Investigation: The Plant Toxin Trap, Brittany, France, 2018.
Overview
Watier-Grillot S et al.. Toxins (Basel) 2023 · PMID 37505726 · DOI 10.3390/toxins15070457
Chili con carne made with undercooked kidney beans made 200 people ill within hours; the bean lectin was detected.
Does the study support the specific claim? Yes · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Investigate an outbreak.
- How was the study done?
Case-control study and lab tests.
- How many people, animals or samples were studied?
200 cases among 1,700 diners.
- What was actually found?
Undercooked kidney beans with active lectin.
- How large was the observed effect?
OR 30.9.
- What do the results mean in everyday life?
Beans must be soaked and boiled properly.
- What are the study's limitations?
One outbreak.
- What does it say about Elawady's specific claim?
- Do the results apply to Germany and Europe?
Directly applicable.
- What can explicitly not be concluded from this study?
It does not show harm from properly cooked beans.
Scientific in-depth review
1. Full reference
- Authors
- Watier-Grillot S et al.
- Journal
- Toxins (Basel)
- Year
- 2023
- Identifier
- PMID 37505726 DOI 10.3390/toxins15070457 · PMC10467087
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref works API
- Retracted
- no
- Corrections
- none
- Extent checked
- full text
- Conflicts of interest and funding
No conflicts declared.
2. Research question
What caused an acute gastroenteritis outbreak at a military dining facility in Brittany?
3. Study design and population
- Study design
- Outbreak report – Foodborne outbreak investigation with case-control study and laboratory haemagglutination testing
- Population
Customers of a military base dining facility (population 1,700)
- Country
France
- Period
July 2018
- Sample size
200 cases; case-control 92 cases, 113 controls
- Inclusion and exclusion criteria
Diners on 5 July 2018.
4. Methods and endpoints
- Exposure / intervention
Chili con carne with undercooked red kidney beans
- Comparator
Non-consumers
- Endpoints
Gastroenteritis; phytohaemagglutinin activity in food
- Statistical methods
Univariate and multivariate case-control analysis
5. Actual results
- Results
Attack rate 12%; median incubation 3.3 h; chili con carne OR 30.9 (95% CI 11.7-69.8) univariate. Raw kidney beans 66,667 HAU/g dry weight; residual activity >400 HAU/g in the dish. Beans were soaked only 1.5 h and cooked at about 80 °C overnight; patients reported hard (undercooked) beans.
- Absolute risks
Attack rate 12% among diners.
- Authors' conclusion
Outbreak caused by phytohaemagglutinin from inadequately cooked kidney beans; routine plant-toxin testing is needed.
6. Strengths
- Analytical epidemiology plus laboratory confirmation
- Full text read
7. Weaknesses
- Few stool samples
- Single outbreak
8. Risk of bias
- Orienting tool
- none applicable
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- low
- Rationale
Well-documented outbreak; exposure clearly identified.
9. Assessment of the statistical interpretation
Very large OR with wide CI typical of outbreak data; dose of cooking error is clear.
10. Relevance to the specific claim
Confirms modern lectin poisoning from undercooked beans (C-LEG-06) and shows the cause was low-temperature cooking, not properly boiled beans (contradicts C-LEG-07).
11. Independent contrary findings
None.
12. Transferability to Germany and Europe
Directly relevant (France).
13. Overall methodological judgement
Strong recent confirmation that preparation, not legumes as such, determines lectin toxicity.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | low |
| Precision of results | moderate |
| 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
Exact human toxic dose.
15. Linked fact checks
- Raw or undercooked red kidney beans cause acute poisoning through the lectin phytohaemagglutinin. – Studies supporting the claim
- Plant lectins in legumes survive digestion, bind to intestinal cells and harm human health, so legumes are harmful even when eaten normally. – Studies contradicting or limiting the claim