Leafy greens and cucurbits are at the centre of the modern fresh-produce outbreak record (E. coli, Salmonella, Listeria).
Original statement
فضلاً عن كونها أكثر أغذية تفشّيات الإشريكية القولونية والسالمونيلا والليستيريا في الأدبيات الحديثة
verbatim according to source. Translation by the project; the Arabic wording is authoritative.
Translation
Leafy greens and cucurbits are at the centre of the modern fresh-produce outbreak record (E. coli, Salmonella, Listeria).
Origin
- Source status
- Archive editors
- Attribution
- Archive editors
- Origin
- https://eltayebat.com/rule/leafy-greens-cucurbits/
- Attribution uncertainty
- Archive editorial text and study selection written by the archive operators, not necessarily by Elawady.
- Claimed mechanism
Microbial contamination of produce eaten raw.
- Claimed health effect
Foodborne infections, HUS, deaths.
- Population concerned
Consumers of raw produce
- Geographic restriction by Elawady
none found
Scientific assessment
Mostly true – Correct at its core, but with limitations or minor inaccuracies.
Certainty of evidence: moderate – Further research may still affect the assessment.
1. What was claimed?
Leafy greens/cucurbits dominate produce outbreaks.
2. What is demonstrably correct?
Leafy vegetables were the single commodity with most outbreak-attributed illnesses in the US 1998-2008 (2.2 million, 22%); documented outbreaks include spinach E. coli O157:H7 (225 cases, 5 deaths), packaged salad Listeria (19 US + 14 Canadian cases), cucumber Salmonella Newport (275 cases).
3. What is wrong or exaggerated?
Outbreaks reflect the large volume of produce eaten raw; most leafy-vegetable illnesses in Painter 2013 were norovirus, often linked to food handling. Deaths were attributed most often to poultry (6.0% of outbreak deaths were attributed to leafy vegetables). A risk from contamination is a hygiene issue, not a property of the vegetables.
4. What remains unclear?
Per-serving absolute risk is not reported in these sources.
5. Which studies support it?
Sharapov 2016; Self 2019; Angelo 2015; Painter 2013.
6. Which studies contradict it?
Painter 2013 (poultry most deaths; produce risk mostly norovirus).
7. What applies to Germany and Europe?
EU hygiene rules and outbreak surveillance apply; outbreaks are rare relative to consumption.
8. What is known about Egypt?
No Egyptian outbreak data reviewed; hygiene of irrigation water and washing are relevant.
9. What practical conclusion is appropriate?
Wash produce, keep the cold chain, and follow advice for high-risk groups; avoiding all greens is not the recommended response.
Assessment details
- Rationale for certainty of evidence
US outbreak-attribution data (Painter 2013) attribute more illnesses to leafy vegetables (22%) than to any other commodity, but mostly norovirus and a smaller share of deaths (6.0%); poultry caused the most deaths. Outbreak data do not translate into a high per-serving risk.
- Source quality
Archive cites genuine outbreak reports; it omits denominators and the comparison with animal foods.
- Regional transferability
US data; European patterns are broadly similar for produce but differ in detail (not reviewed in depth).
- Individual exceptions
Pregnant women, elderly and immunocompromised people are at higher risk (e.g. Listeria) and should follow food-safety advice.
- Regional scope of the claim
- not specified
- Last reviewed
- 26 October 2026 provisional
Scientific evidence in detail
Scientifically well supported – The claim agrees with consistent, high-quality evidence.
Research question: Are leafy greens and cucurbits leading vehicles in the modern fresh-produce foodborne outbreak record?
Research question in detail (PECO)
- Population
- Consumers in surveillance systems (US, EU)
- Intervention or exposure
- Leafy greens, cucurbits (melons, cucumbers)
- Comparison
- Other foods
- Geographic scope
- production- and surveillance-dependent (US, EU data)
- Outcomes
- outbreaks
- illnesses
- hospitalisations
- deaths
Study results as reported by the authors. Our assessment follows below.
What speaks for the claim?
Which foods cause food poisoning in the US
Painter JA et al.. Emerg Infect Dis 2013 · PMID 23622497 · DOI 10.3201/eid1903.111866 Otherfull text checkedPainter 2013 CDC attribution.
- Actual result
- Leafy vegetables 22% of illnesses (largest commodity), 6.0% of deaths; poultry most deaths.
- Methodological quality
- moderate-high
- Relevance
- direct
- Limitations
- Outbreak data only.
EFSA: raw leafy greens top plant-food hazard
EFSA Panel on Biological Hazards (BIOHAZ). EFSA J 2013 · PMID 42124987 · DOI 10.2903/j.efsa.2013.3025 Risk assessmentabstract checkednewly addedEFSA BIOHAZ 2013 risk ranking.
- Actual result
- Top-ranked combination: Salmonella and raw leafy greens; melons also ranked; FoNAO 5% of outbreak deaths excluding 2011 O104.
- Methodological quality
- authoritative
- Relevance
- direct (EU)
- Limitations
- Outbreak data.
Leafy greens: frequent but rarely deadly outbreak source
Herman KM et al.. Epidemiol Infect 2015 · PMID 25697407 · DOI 10.1017/S0950268815000047 Otherabstract checkednewly addedHerman 2015 US leafy-vegetable outbreaks 1973-2012.
- Actual result
- 606 outbreaks, 20,003 illnesses, 19 deaths; norovirus 55%; ill food worker in 31%.
- Methodological quality
- moderate
- Relevance
- direct
- Limitations
- Surveillance bias.
What speaks against the claim?
No high-quality evidence against the claim was found.
What does the overall evidence say?
Editorial assessment based on the studies above – not itself a study result.
Which position is better supported?
Correct: leafy greens are among the most frequent outbreak vehicles in US and EU data, and melons/cucumbers have caused notable outbreaks. Per-serving risk and fatality are low; many outbreaks stem from food handling.
Why some studies weigh more
National surveillance analyses from two regions agree.
Is a causal relationship established? Yes, established Outbreak investigations link vehicles to cases.
Remaining uncertainty
Per-serving risk.
Justified conclusion
Mostly true as a description of the outbreak record; it does not imply that vegetables are unsafe to eat.
Why do studies seem to disagree?
Leafy greens lead in illnesses but not in deaths (poultry); both are true and answer different questions.
Does this depend on the country?
- General biological effects
- Pathogen biology universal.
- Eating habits
- Raw salads are common in Egypt.
- Origin of the food
- Irrigation water and handling practices drive contamination.
- Contaminants
- Microbial contamination.
- National production conditions
- Egyptian outbreak surveillance data not found.
- Legal rules
- EU and US produce-safety rules.
- Actual monitoring data
- US/EU surveillance.
A regional difference that changes the conclusion is not supported by robust data.
Statistical re-check
- Case fatality and hospitalisation proportions – Hospitalised 5.1%; CFR 0.095%. recalculated
- Case fatality – CFR 0.21%. recalculated
Certainty of the overall evidence (GRADE, simplified)
- Main outcome
- Share of produce-associated outbreaks attributed to leafy greens
- Starting level
- low (observational studies)
- Reasons for upgrading
- consistency across countries and decades
- Result
- moderate
Simplified assessment by a single reviewer, following the GRADE approach; not a formal GRADE panel. GRADE rates the body of evidence for one outcome, not individual studies.
Search strategy
Documented literature searches for this review (search strings in the original database syntax).
| Database | Date | Search | Looking for | Hits | Included |
|---|---|---|---|---|---|
| PubMed | 26 October 2026 | (outbreak*) AND (produce OR "leafy greens" OR "leafy vegetables") AND (United States OR Europe) AND (2010:2026[dp]) AND (review OR surveillance OR attribution) | both directions | 2243 | |
| Europe PMC | 26 October 2026 | TITLE:(outbreak* AND (produce OR "leafy greens" OR "leafy vegetables" OR "fresh vegetables" OR "fruits and vegetables")) | both directions | 45 | |
| Europe PMC | 26 October 2026 | "pathogens in food of non-animal origin" AND EFSA | both directions | 8 | |
| CDC IFSAC website | 26 October 2026 | https://www.cdc.gov/ifsac/php/data-research/annual-report-2022.html (HTTP 403, not used) | guidelines | 0 |
Open questions
Egyptian outbreak data.
How deeply was this checked?
7 linked studies: 1 checked in full text (0 of them with a structured risk-of-bias assessment), 6 on the basis of the abstract, 0 bibliographically only. No formal assessment with two independent reviewers and no independent human expert review has taken place yet.
Last scientific review: 26 October 2026
History of the verdict
- 25 October 2026 · Phase 1 · Initial assessment: Mostly true (moderate)
- 26 October 2026 · Phase 4 (systematic evidence review) · Re-examined with extended evidence; verdict unchanged: Mostly true (moderate)
New surveillance analyses confirm the existing verdict.
New sources: I-VEG-132 I-VEG-133 I-VEG-134
In plain language
Leafy greens are indeed often linked to foodborne outbreaks, because they are eaten raw and in large amounts. In the United States, more outbreak illnesses were linked to leafy vegetables than to any other single food group, mostly norovirus. More deaths, however, were linked to poultry. Contamination is a hygiene problem that can be reduced by washing, proper storage and controls, and it does not make greens harmful in themselves.
Studies on this claim
Studies supporting the claim (7)
-
E. coli outbreak from bagged spinach, US 2006
Sharapov UM et al.. J Food Prot 2016 · PMID 28221950 · DOI 10.4315/0362-028X.JFP-15-556Outbreak reportcited by the Tayebat archiveabstract checked★ key study225 people fell ill and 5 died after eating contaminated bagged spinach.
Does the study support the specific claim? Partly · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Investigate outbreak
- How was the study done?
Outbreak investigation
- How many people, animals or samples were studied?
225 cases
- What was actually found?
Bagged spinach source
- How large was the observed effect?
5 deaths
- What do the results mean in everyday life?
Contamination incidents happen; hygiene matters.
- What are the study's limitations?
Single event
- What does it say about Elawady's specific claim?
Shows contamination risk
- Do the results apply to Germany and Europe?
Moderate
- What can explicitly not be concluded from this study?
Cannot show spinach is inherently harmful.
-
Listeria in packaged salads
Self JL et al.. Emerg Infect Dis 2019 · PMID 31310227 · DOI 10.3201/eid2508.180761Outbreak reportcited by the Tayebat archiveabstract checked33 listeriosis cases linked to salads from one factory.
Does the study support the specific claim? Partly · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Investigate outbreak
- How was the study done?
Genomic outbreak study
- How many people, animals or samples were studied?
33 cases
- What was actually found?
One facility
- How large was the observed effect?
Not applicable
- What do the results mean in everyday life?
High-risk groups need care with packaged salads.
- What are the study's limitations?
Single event
- What does it say about Elawady's specific claim?
Partly supports
- Do the results apply to Germany and Europe?
Moderate
- What can explicitly not be concluded from this study?
Cannot show salads are generally harmful.
-
Salmonella from cucumbers, US 2014
Angelo KM et al.. MMWR Morb Mortal Wkly Rep 2015 · PMID 25695319Outbreak reportcited by the Tayebat archiveabstract checked275 people infected; cucumbers likely source.
Does the study support the specific claim? Partly · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Find source
- How was the study done?
Outbreak report
- How many people, animals or samples were studied?
275 patients
- What was actually found?
Cucumbers
- How large was the observed effect?
Not applicable
- What do the results mean in everyday life?
Contamination events occur.
- What are the study's limitations?
Regional
- What does it say about Elawady's specific claim?
Partly
- Do the results apply to Germany and Europe?
Low
- What can explicitly not be concluded from this study?
Cannot show cucumbers are inherently harmful.
-
Which foods cause food poisoning in the US
Painter JA et al.. Emerg Infect Dis 2013 · PMID 23622497 · DOI 10.3201/eid1903.111866Otherindependent cross-checkfull text checked★ key studyLeafy vegetables caused the most outbreak illnesses (22%), poultry the most deaths.
Does the study support the specific claim? Partly · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Attribute illness
- How was the study done?
Model on outbreak data
- How many people, animals or samples were studied?
US 1998-2008
- What was actually found?
Leafy vegetables 22% illnesses
- How large was the observed effect?
6% deaths
- What do the results mean in everyday life?
Hygiene matters for greens and poultry.
- What are the study's limitations?
Outbreak-based
- What does it say about Elawady's specific claim?
Partly supports
- Do the results apply to Germany and Europe?
Moderate
- What can explicitly not be concluded from this study?
Cannot give per-serving risk.
-
Leafy greens: frequent but rarely deadly outbreak source
Herman KM et al.. Epidemiol Infect 2015 · PMID 25697407 · DOI 10.1017/S0950268815000047Otherindependent cross-checkabstract checked★ key studyOver 40 years, US leafy-vegetable outbreaks caused 20,003 illnesses and 19 deaths; many involved infected food workers.
606 US leafy-vegetable outbreaks 1973-2012; mostly norovirus; low fatality.
Does the study support the specific claim? Yes · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Describe US leafy-vegetable outbreaks.
- How was the study done?
Surveillance review.
- How many people, animals or samples were studied?
606 outbreaks.
- What was actually found?
Large outbreaks, mostly norovirus, low fatality.
- How large was the observed effect?
CFR ~0.1%.
- What do the results mean in everyday life?
Washing hands and safe handling matter as much as farming.
- What are the study's limitations?
Outbreak data only.
- What does it say about Elawady's specific claim?
Supports the claim with context.
- Do the results apply to Germany and Europe?
US.
- What can explicitly not be concluded from this study?
Cannot estimate risk per serving.
-
Raw produce causes a growing share of US outbreaks
Bennett SD et al.. Epidemiol Infect 2018 · PMID 29923474 · DOI 10.1017/S0950268818001620Otherindependent cross-checkabstract checkedRaw produce caused 972 outbreaks in 1998-2013, rising from 8% to 16% of outbreaks with a known food; leafy row crops led.
Raw produce share of outbreaks doubled; vegetable row crops most common.
Does the study support the specific claim? Yes · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Analyse raw-produce outbreaks.
- How was the study done?
Surveillance analysis.
- How many people, animals or samples were studied?
972 outbreaks.
- What was actually found?
Increasing share; row crops most common.
- How large was the observed effect?
72 deaths / 34,674 illnesses.
- What do the results mean in everyday life?
Produce safety matters, but serious outcomes are rare.
- What are the study's limitations?
Outbreak data only.
- What does it say about Elawady's specific claim?
Supports the claim.
- Do the results apply to Germany and Europe?
US.
- What can explicitly not be concluded from this study?
Cannot give per-serving risk.
-
EFSA: raw leafy greens top plant-food hazard
EFSA Panel on Biological Hazards (BIOHAZ). EFSA J 2013 · PMID 42124987 · DOI 10.2903/j.efsa.2013.3025Risk assessmentindependent cross-checkabstract checked★ key studyEFSA ranked Salmonella in raw leafy greens as the highest-risk plant food combination; outside the 2011 sprout outbreak, plant foods caused 5% of outbreak deaths.
EFSA ranked Salmonella in raw leafy greens top; melons also ranked.
Does the study support the specific claim? Yes · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Rank pathogen risks in plant foods.
- How was the study done?
Risk ranking.
- How many people, animals or samples were studied?
EU outbreaks 2007-2011.
- What was actually found?
Leafy greens top; melons ranked.
- How large was the observed effect?
FoNAO 10% outbreaks.
- What do the results mean in everyday life?
Wash and handle salads safely; serious cases are uncommon.
- What are the study's limitations?
Outbreak data.
- What does it say about Elawady's specific claim?
Supports the claim.
- Do the results apply to Germany and Europe?
EU.
- What can explicitly not be concluded from this study?
No per-serving risk.
No study in this group is marked as key.
Studies contradicting or limiting the claim (0)
No studies in this group.
Studies with mixed or unclear results (0)
No studies in this group.
Regional context
Germany / EU
EU hygiene rules and outbreak surveillance apply; outbreaks are rare relative to consumption.
Egypt
No Egyptian outbreak data reviewed; hygiene of irrigation water and washing are relevant.
- Food-safety governance and official controls
- Pesticide residues in fruit and vegetables on the EU/German market (incl. imports from Egypt)
- Pesticide residues in produce sold on the Egyptian domestic market
- Antibiotic (veterinary drug) residues in poultry meat and eggs
- Antimicrobial use in food animals and antibiotic growth promoters
- Hormones in poultry, meat, milk and farmed fish
- Dioxins, PCBs and PFAS in eggs and other animal foods
- Aflatoxin M1 in milk and dairy products
- Aflatoxins in groundnuts (peanuts)
- Heavy metals in fish
- Farmed fish (aquaculture): drugs, water source and controls
- Nitrate in leafy vegetables
- Microbiological safety of fresh produce, herbs and spices
- Import controls and the meaning of RASFF notifications for Egyptian products
What applies in my country?
General scientific assessment
Mostly true Leafy greens are frequent outbreak vehicles, but the risk per serving is low and manageable through hygiene.
The following areas of food safety are relevant to this statement:
- Pesticides and pesticide residues
- Veterinary medicines and antibiotics
- Hormonal growth promoters
- Contaminants (heavy metals, PFAS, PCBs, dioxins, nitrate)
- Pathogens (Salmonella, Campylobacter, etc.)
Eggs · Poultry · Dairy · Fish and seafood · Red meat · Fruit and vegetables
Choose a country to see the checked information for it.
Limits: legal rules describe what is allowed, not what every single food contains. Measurement data come from samples and are meaningful only together with their method details.
Country of residence or purchase Compare with another country
References
- Multistate Outbreak of Escherichia coli O157:H7 Infections Associated with Consumption of Fresh Spinach: United States, 2006.. Sharapov UM et al.. J Food Prot 2016 · PMID 28221950 · DOI 10.4315/0362-028X.JFP-15-556
- Multistate Outbreak of Listeriosis Associated with Packaged Leafy Green Salads, United States and Canada, 2015-2016.. Self JL et al.. Emerg Infect Dis 2019 · PMID 31310227 · DOI 10.3201/eid2508.180761
- Outbreak of Salmonella Newport infections linked to cucumbers--United States, 2014.. Angelo KM et al.. MMWR Morb Mortal Wkly Rep 2015 · PMID 25695319
- Attribution of foodborne illnesses, hospitalizations, and deaths to food commodities by using outbreak data, United States, 1998-2008.. Painter JA et al.. Emerg Infect Dis 2013 · PMID 23622497 · DOI 10.3201/eid1903.111866
- Outbreaks attributed to fresh leafy vegetables, United States, 1973-2012.. Herman KM et al.. Epidemiol Infect 2015 · PMID 25697407 · DOI 10.1017/S0950268815000047
- Produce-associated foodborne disease outbreaks, USA, 1998-2013.. Bennett SD et al.. Epidemiol Infect 2018 · PMID 29923474 · DOI 10.1017/S0950268818001620
- Scientific Opinion on the risk posed by pathogens in food of non-animal origin. Part 1 (outbreak data analysis and risk ranking of food/pathogen combinations).. EFSA Panel on Biological Hazards (BIOHAZ). EFSA J 2013 · PMID 42124987 · DOI 10.2903/j.efsa.2013.3025