Measurement / residue studyindependent cross-checkabstract checked I-FAT-106 standard review
Some Egyptian olive oil contained illegal dyes
Optimization and validation of a rapid LC-MS/MS method for the detection and quantification of illegal dyes in olive oil from Egyptian markets.
Overview
Ragab M et al.. Food Chem 2025 · PMID 40446662 · DOI 10.1016/j.foodchem.2025.144924
Sudan Yellow in 5% of 870 samples; other dyes rarer.
Does the study support the specific claim? Partly · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Detect banned dyes in olive oil.
- How was the study done?
Lab survey.
- How many people, animals or samples were studied?
870 samples.
- What was actually found?
Dyes in a minority.
- How large was the observed effect?
Up to ~6% positive.
- What do the results mean in everyday life?
Buy olive oil from reliable sources.
- What are the study's limitations?
Only dyes tested.
- What does it say about Elawady's specific claim?
Partly supports adulteration concern.
- Do the results apply to Germany and Europe?
Egypt.
- What can explicitly not be concluded from this study?
Cannot show olive oil itself is unhealthy.
Scientific in-depth review
1. Full reference
- Authors
- Ragab M et al.
- Journal
- Food Chem
- Year
- 2025
- Identifier
- PMID 40446662 DOI 10.1016/j.foodchem.2025.144924
- Verification
- verified – PubMed efetch 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
No competing interests declared.
2. Research question
Are banned dyes present in olive oil sold in Egypt?
3. Study design and population
- Study design
- Measurement / residue study – Analytical method validation plus market survey
- Population
Olive oil samples from Egyptian local markets
- Country
Egypt
- Period
not stated in abstract
- Sample size
870 samples
- Inclusion and exclusion criteria
Market samples
4. Methods and endpoints
- Exposure / intervention
Banned (Sudan) dyes
- Comparator
Legal absence
- Endpoints
Detection and concentration
- Statistical methods
Method validation per CIR (EU) 2021/808
5. Actual results
- Results
Detected: Sudan Yellow 5%, Sudan I 0.9%, Sudan III 0.2%, Sudan Red G 0.1%, Sudan II 0.1%, Sudan Red B 0.1% of samples. LOD 0.1-0.3 ug/kg.
- Absolute risks
not applicable
- Authors' conclusion
The method is applicable; banned dyes were found in Egyptian market olive oil.
6. Strengths
- Large Egyptian sample
- Validated method
7. Weaknesses
- Only dyes tested (not oil substitution or other fraud)
- Sampling frame not described in abstract
8. Risk of bias
- Orienting tool
- none applicable
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- not assessable
- Rationale
Analytical survey.
9. Assessment of the statistical interpretation
At most about 6.4% of samples contained any tested dye (sum of shares; stats/C-FAT-04_oils.py).
10. Relevance to the specific claim
Confirms that olive oil adulteration occurs on the Egyptian market, supporting a concern about quality, but most samples were free of the tested dyes, contradicting 'it is all fake'.
11. Independent contrary findings
Other adulteration types not tested.
12. Transferability to Germany and Europe
Egypt-specific; EU has its own fraud controls.
13. Overall methodological judgement
Partial support for the adulteration concern; not a reason to consider authentic olive oil harmful.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | indirect |
| Reproducibility | unknown |
| Consistency with the overall evidence | unknown |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Extent of oil-substitution fraud in Egypt.