Nezam El-Tayebat Fact CheckA scientific assessment of the “نظام الطيبات” nutrition system
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Mostly true True only under certain conditions Certainty of evidence: moderate provisional C-EGG-09

Salmonella is far more common in caged egg production than in cage-free systems (44% vs 3.2%).

Safety note: Pregnant women, infants, older and immunocompromised people should avoid raw or undercooked eggs, regardless of housing system; Salmonella has been found in retail eggs in Egypt and the Gulf region, and cage-free or backyard eggs are not automatically safer. Eggs should be stored cool and cooked until white and yolk are firm.
In short: The 44% vs 3.2% figures are cited correctly and the overall direction is supported, but they come from farm dust and droppings, not eggs; hygiene and farm size matter as much as cages, and in Egypt one study found cleaner eggs in well-run cage farms. All eggs should be stored cool and cooked thoroughly for vulnerable groups.
Conclusion: Cage systems are associated with more Salmonella on farms, but contamination of eggs on sale in the EU is rare.
  1. Original statement
  2. Scientific assessment
  3. Scientific evidence in detail
  4. In plain language
  5. Studies on this claim
  6. Regional context
  7. What applies in my country?
  8. References

Original statement

هذا قبل أن نتحدث عن السالمونيلا التي بلغ انتشارها في بيئة الأقفاص 44% مقابل 3.2% فقط في النظام الحر بحسب J Food Prot 2019

verbatim according to source. Translation by the project; the Arabic wording is authoritative.

Translation

Salmonella is far more common in caged egg production than in cage-free systems (44% vs 3.2%).

Origin

Source status
Archive editors
Attribution
Archive editors (not Elawady)
Origin
https://eltayebat.com/rule/industrial-eggs/
Attribution uncertainty
Narrative and study selection written by the archive operators; the archive states the forbidden section is documented independently of Dr. Diaa's words.
Claimed mechanism

Dense caged housing.

Claimed health effect

Salmonellosis.

Population concerned

general population (not specified)

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?

Cage systems carry much more Salmonella than cage-free systems.

2. What is demonstrably correct?

In the NZ survey, 44.0% (33/75) of samples from caged systems vs 3.2% (4/126) from cage-free systems were positive (A-EGG-10). EFSA (2019) found that the overall evidence points to lower Salmonella occurrence in non-cage systems (e.g. Austrian baseline survey 34.4% of cage vs 7.9% of non-cage flocks) and that higher stocking density, larger farms and stress increase Salmonella. EFSA/ECDC (2024 data) name Salmonella in 'eggs and egg products' as the agent/food pair of most concern in the EU.

3. What is wrong or exaggerated?

The 44% refers to farm-environment samples, not to eggs; Salmonella was not detected on 16 of 28 farms, and S. Enteritidis was not found at all. The study authors note that many practices differ between systems. In EU monitoring 2024, only 0.31% of 'eggs and egg products' samples were Salmonella-positive. The archive's own antibiotic source (A-EGG-09) is a review stating that US poultry foods are very safe.

4. What remains unclear?

How much of the cage effect is due to cages per se versus farm size, stocking density, age of buildings and hygiene; EFSA calls the evidence conflicting, a systematic review lists cage housing among many risk factors (I-EGG-123), and counter-examples exist (Egypt, I-EGG-125; Chile, where Salmonella Enteritidis was found only in cage-free eggs, I-EGG-132). Most studies predate the 2012 EU ban of conventional cages. The 44% vs 3.2% figures come only from the NZ study.

5. Which studies support it?

A-EGG-10 (source of the 44% vs 3.2% figures); I-EGG-15 (direction only; evidence described as conflicting).

6. Which studies contradict it?

I-EGG-14 (low sample positivity in EU eggs), which limits the practical relevance.

7. What applies to Germany and Europe?

Directive 1999/74/EC banned unenriched cages from 1 January 2012 (enriched cages >= 750 cm2 per hen still allowed; Germany has its own stricter national rules, not reviewed here). Salmonella reduction targets for laying-hen flocks apply; in 2024 the EU flock prevalence of target serovars in adult laying hens was 1.6%.

8. What is known about Egypt?

Egyptian data are limited. In Sharkia governorate, Salmonella was isolated from 3.6% of retail table egg contents, often multidrug-resistant (I-EGG-126). A small study of seven Egyptian layer farms found that closed battery (cage) farms with high biosecurity had less bacterial contamination of eggs than open deep-litter and backyard systems (I-EGG-125), i.e. the opposite of a simple 'cages = more Salmonella' rule. In the UAE, shell contamination was found only in cage-laid retail eggs (11.6% vs 0%), with clean contents (I-EGG-124). Production systems and control programmes differ from the EU.

9. What practical conclusion is appropriate?

Cage-free systems tend to have less Salmonella; regardless of system, eggs should be stored cool and cooked thoroughly for vulnerable people.

Assessment details

Rationale for certainty of evidence

The NZ numbers are correctly cited (A-EGG-10). An EFSA review describes the evidence on cage vs non-cage housing as 'conflicting' (some studies show the reverse), concludes that overall it 'points to' lower Salmonella occurrence in non-cage systems with the mechanism unclear (flock size, stocking density, cleaning), and found conclusive evidence for effects of stocking density and farm size; most studies predate the 2012 EU ban of conventional cages. Limitations: the NZ figures are environmental samples (dust, faeces), not eggs; systems differ in many practices.

Source quality

Archive editorial; numbers match the abstract.

Regional transferability

NZ farms had no Salmonella Enteritidis (the main egg-associated serovar). In the EU, unenriched cages are banned since 2012 and national Salmonella control programmes apply.

Individual exceptions

Raw/undercooked eggs are a higher risk for infants, pregnant women, older and immunocompromised people.

Regional scope of the claim
depends on production conditions
Last reviewed
26 October 2026 provisional

Scientific evidence in detail

True only under certain conditions – The claim holds only for certain doses, groups of people, preparations or circumstances.

Research question: Is Salmonella far more common in caged egg production than in cage-free systems (44% vs 3.2%), and does this translate into more contaminated eggs on sale?

Research question in detail (PECO)
Population
Laying-hen farms and retail eggs (NZ, EU, Middle East, Egypt)
Intervention or exposure
Cage housing
Comparison
Cage-free (barn, free-range, backyard) housing
Geographic scope
production-dependent
Outcomes
  • Salmonella in farm environment
  • Salmonella on eggshells and in egg contents

Study results as reported by the authors. Our assessment follows below.

What speaks for the claim?

What speaks against the claim?

What does the overall evidence say?

Editorial assessment based on the studies above – not itself a study result.

Which position is better supported?

On average, cage systems (especially older, larger, multi-age farms) are associated with more Salmonella in the farm environment, and the archive cites the NZ numbers correctly. However, biosecurity, flock size and hygiene matter as much as housing, counter-examples exist (Egypt, Chile), and contamination of eggs on sale is low in monitored markets.

Why some studies weigh more

EFSA's assessment and a systematic review support the direction; single surveys on both sides are small. Egyptian data are weak but locally relevant.

Is a causal relationship established? Possible, not established Housing is confounded with flock size, farm age and biosecurity; a pure cage effect is not isolated.

Remaining uncertainty

Egyptian prevalence by housing system; effect of enriched cages.

Justified conclusion

Mostly true as a farm-level association; it does not mean cage-free eggs are Salmonella-free or that cooking can be skipped.

Why do studies seem to disagree?

NZ/UAE/EFSA vs Egypt/Chile: different sample types (environment vs shell vs contents), biosecurity levels and production contexts. The Egyptian study compares high-biosecurity battery farms with low-biosecurity backyard systems, which is a different contrast.

Does this depend on the country?
General biological effects
Salmonella Enteritidis can contaminate egg contents; cooking kills it.
Eating habits
Raw or soft eggs in traditional dishes increase risk.
Origin of the food
Backyard eggs are not automatically safer.
Contaminants
Salmonella (often multidrug-resistant in Egyptian isolates).
National production conditions
Egypt has both battery and backyard systems with variable biosecurity.
Legal rules
EU: unenriched cages banned since 2012; Salmonella control targets for laying flocks.
Actual monitoring data
EU eggs 0.31% positive (2024); Egyptian retail egg contents 3.6% in one governorate study.

A regional difference that changes the conclusion is not supported by robust data.

Statistical re-check
  • Proportions, CIs and exact test – 44.0% (33.3-55.3) vs 3.2% (1.2-7.9), Fisher p = 6e-13; ignores clustering within farms (16/28 farms negative), so precision is overstated. recalculated
  • Proportions and exact test – 11.6% (8.5-15.5) vs 0% (0-6.0), Fisher p = 0.0017; producer clustering not accounted for; contents 0/380 (upper bound about 0.8%). recalculated
Certainty of the overall evidence (GRADE, simplified)
Main outcome
Salmonella occurrence in cage vs cage-free laying systems
Starting level
low (observational studies)
Reasons for downgrading
  • inconsistency
Reasons for upgrading
  • consistent direction in larger datasets (EFSA, systematic review)
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.

Clinical guidelines and official statements checked
  • NHS (UK National Health Service): Foods to avoid in pregnancy (eggs and liver sections) (2026 (accessed)) · Original publication
    Hen eggs with the British Lion stamp or 'Laid in Britain' may be eaten raw, runny or well-cooked in pregnancy; other hen eggs and duck, goose and quail eggs only well-cooked. Liver and liver products should be avoided because of high vitamin A.
  • CDC: Eggs and Egg Products (food safety page) (2026) · Original publication could not be retrieved; content not used
Search strategy

Documented literature searches for this review (search strings in the original database syntax).

DatabaseDateSearchLooking forHitsIncluded
PubMed26 October 2026Salmonella[ti] AND (laying hen*[ti] OR layer*[ti] OR egg*[ti]) AND (housing[tiab] OR cage*[tiab]) AND (meta-analysis[pt] OR systematic review[pt] OR risk factor*[ti])both directions11
Europe PMC26 October 2026TITLE:Salmonella AND (TITLE:"table egg*" OR TITLE:"eggs") AND (Egypt*) AND (TITLE:prevalence OR TITLE:occurrence OR TITLE:detection OR TITLE:isolation)both directions3
PubMed26 October 2026Salmonella[ti] AND egg*[ti] AND Egypt*[tiab]both directions0
PubMed26 October 2026Salmonella AND (egg OR eggs OR "laying hens" OR layer) AND Egyptboth directions61
Europe PMC26 October 2026TITLE:Salmonella AND (TITLE:"cage" OR TITLE:"cages" OR TITLE:"cage-free" OR TITLE:"free-range" OR TITLE:"housing system*" OR TITLE:"production system*") AND (TITLE:laying OR TITLE:layer* OR TITLE:egg*)both directions36
PubMed26 October 2026"Cochrane Database Syst Rev"[ta] AND (Salmonella OR "egg allergy" OR snoring) AND (diet OR egg)both directions3
CDC website (fetch)26 October 2026https://www.cdc.gov/food-safety/foods/eggs.htmlguidelines1
NHS website (fetch)26 October 2026https://www.nhs.uk/pregnancy/keeping-well/foods-to-avoid/guidelines1

Open questions

Representative Egyptian survey of Salmonella in eggs by housing system.

How deeply was this checked?

9 linked studies: 4 checked in full text (1 of them with a structured risk-of-bias assessment), 5 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
  1. 25 October 2026 · Phase 1 · Initial assessment: Mostly true (moderate)
  2. 26 October 2026 · Phase 4 (systematic evidence review) · Re-examined with extended evidence; verdict unchanged: Mostly true (moderate)
    A systematic review and UAE retail data support the direction; small Egyptian and Chilean studies show counter-examples, consistent with EFSA's description of the evidence as conflicting. The conclusion is unchanged; the Egyptian context is now documented.
    New sources: I-EGG-123 I-EGG-124 I-EGG-125 I-EGG-126 I-EGG-132

In plain language

The archive says caged egg farms have much more Salmonella than cage-free farms. A New Zealand study did find this, and the European Food Safety Authority also concluded that non-cage systems tend to have less Salmonella. However, the samples were dust and droppings from barns, not eggs, and in EU testing only about 3 in 1,000 egg samples were positive. Cooking eggs well protects against Salmonella.

Studies on this claim

Studies supporting the claim (4)

  • Salmonella on New Zealand egg farms

    Kingsbury JM et al.. J Food Prot 2019 · PMID 31742446 · DOI 10.4315/0362-028X.JFP-19-159
    Cross-sectional studycited by the Tayebat archiveabstract checked★ key study

    Barn samples from cage farms were far more often positive (44%) than from cage-free farms (3%); most farms had no Salmonella.

    Salmonella is far more common in caged egg production than in cage-free systems (44% vs 3.2%).

    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?

    What is the prevalence and type of Salmonella in the New Zealand egg production environment?

    How was the study done?

    Cross-sectional survey of Salmonella in feed, laying sheds and packhouses of commercial layer farms with genomic analysis

    How many people, animals or samples were studied?

    323 samples from 28 farms; 28 commercial layer farms

    What was actually found?

    43/323 (13.3%) positive; 16/28 farms negative. Dust 28.4%, boot/manure belt 16.4%, faeces 10.4%, packhouse surfaces 5.7%, feed 3.0%. Caged 33/75 (44.0%) vs cage-free 4/126 (3.2%). No S. Enteritidis isolated.

    How large was the observed effect?

    Proportions; P<0.001 for cage vs cage-free

    What do the results mean in everyday life?

    Housing and hygiene influence Salmonella on farms.

    What are the study's limitations?

    Environmental samples, not eggs; Confounding by practices; Few positive farms drive results

    What does it say about Elawady's specific claim?

    Supports the cage vs cage-free difference.

    Do the results apply to Germany and Europe?

    Moderate; EFSA review agrees on direction.

    What can explicitly not be concluded from this study?

    Cannot tell how many eggs were contaminated.

    Scientific details →

  • EFSA: Salmonella in poultry flocks

    EFSA BIOHAZ Panel. EFSA J 2019 · PMID 32626222 · DOI 10.2903/j.efsa.2019.5596
    Risk assessmentindependent cross-checkfull text, structured risk-of-bias assessment★ key study

    Overall, laying-hen flocks kept outside cages tend to have less Salmonella, but studies conflict; crowding, large farms and stress clearly increase it.

    Salmonella is far more common in caged egg production than in cage-free systems (44% vs 3.2%).

    Does the study support the specific claim? Yes · 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?

    Contributory factors and control options for Salmonella in EU poultry

    How was the study done?

    EFSA scientific opinion with attribution modelling and risk-factor reviews

    How many people, animals or samples were studied?

    Not applicable; EU poultry flocks

    What was actually found?

    Evidence 'points to' lower Salmonella in non-cage than cage flocks (e.g. Austria 34.4% vs 7.9% of flocks), but some studies found the opposite and the cause is unclear. Crowding, large farms and stress conclusively increase Salmonella. A 1% target would cut layer-related human cases by 53.4% (about 254,400 cases).

    How large was the observed effect?

    Attribution modelling; reviews

    What do the results mean in everyday life?

    Better housing and hygiene reduce Salmonella.

    What are the study's limitations?

    Housing studies mostly older than the 2012 cage ban; confounded by flock size and density; incomplete national data; model estimates with wide uncertainty

    What does it say about Elawady's specific claim?

    Supports the direction (cages worse on average) but not the specific '44% vs 3.2%' figures or a large, consistent difference.

    Do the results apply to Germany and Europe?

    Directly EU.

    What can explicitly not be concluded from this study?

    No egg-level risk numbers for consumers; cannot separate the cage effect from flock size and stocking density.

    Scientific details →

  • Cages are one of many Salmonella risk factors on egg farms

    Denagamage T et al.. Avian Dis 2015 · PMID 26473681 · DOI 10.1637/10997-120214-Reg
    Systematic reviewindependent cross-checkabstract checked

    Cage housing, large flocks, rodents and poor cleaning were linked to Salmonella on layer farms.

    Cage housing identified as a risk factor for Salmonella on layer premises, among many others.

    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?

    Identify Salmonella risk factors in layer farms.

    How was the study done?

    Systematic review.

    How many people, animals or samples were studied?

    17 studies.

    What was actually found?

    Multiple risk factors including cage housing.

    How large was the observed effect?

    Eggshell positivity 59x higher when faeces positive.

    What do the results mean in everyday life?

    Farm hygiene and size matter at least as much as cages.

    What are the study's limitations?

    Observational.

    What does it say about Elawady's specific claim?

    Partly supports it.

    Do the results apply to Germany and Europe?

    Moderate.

    What can explicitly not be concluded from this study?

    It cannot isolate a pure cage effect.

    Scientific details →

  • UAE supermarket eggs: Salmonella found only on shells of cage eggs

    Habib I et al.. Food Microbiol 2026 · PMID 41963064 · DOI 10.1016/j.fm.2026.105092
    Cross-sectional studyindependent cross-checkabstract checked★ key study

    11.6% of cage-egg packs had Salmonella on the shell vs none of 60 cage-free packs; egg contents were clean.

    UAE retail: shell Salmonella in 11.6% of cage-laid vs 0% of cage-free packs; contents 0%.

    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?

    Measure Salmonella in retail eggs.

    How was the study done?

    Retail survey with genome sequencing.

    How many people, animals or samples were studied?

    380 packs.

    What was actually found?

    Shell contamination only in cage-laid eggs; no contamination inside eggs.

    How large was the observed effect?

    11.6% vs 0%.

    What do the results mean in everyday life?

    Handle and cook eggs properly; cage eggs had more shell contamination in this survey.

    What are the study's limitations?

    Few cage-free samples.

    What does it say about Elawady's specific claim?

    Partly supports the cage comparison.

    Do the results apply to Germany and Europe?

    Regional.

    What can explicitly not be concluded from this study?

    It cannot show illness risk.

    Scientific details →

Studies contradicting or limiting the claim (3)

  • EU zoonoses report 2024

    EFSA, ECDC. EFSA J 2025 · PMID 41377167 · DOI 10.2903/j.efsa.2025.9759
    Otherindependent cross-checkfull text checked★ key study

    Campylobacter and Salmonella are the most common food-borne infections in the EU; about 5% of fresh chicken samples and 0.3% of egg samples had Salmonella.

    Salmonella is far more common in caged egg production than in cage-free systems (44% vs 3.2%).

    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?

    Occurrence of zoonoses and zoonotic agents in humans, food, animals and feed in the EU, 2024

    How was the study done?

    EU surveillance report under Zoonoses Directive 2003/99/EC

    How many people, animals or samples were studied?

    e.g., 95,954 fresh broiler meat samples; 12,327 egg samples; 27 EU Member States, UK (NI), 8 non-MS

    What was actually found?

    Campylobacteriosis 63.7% of confirmed zoonosis cases, salmonellosis second. Salmonella-positive: fresh meat from broilers 4.9%, turkeys 4.7%, eggs and egg products 0.31%. Adult laying-hen flock Salmonella prevalence 4.0%, target serovars 1.6%. Salmonella in eggs and egg products = agent/food pair of most concern; broiler meat most frequently implicated in strong-evidence Campylobacter outbreaks. Campylobacter PHC 1000 CFU/g on neck skin.

    How large was the observed effect?

    Descriptive; trend analyses

    What do the results mean in everyday life?

    Poultry germs are a real but controllable risk.

    What are the study's limitations?

    Reporting differences between countries; Operator vs official sampling differ

    What does it say about Elawady's specific claim?

    Supports existence of pathogens; contradicts exaggerated prevalence.

    Do the results apply to Germany and Europe?

    Directly EU.

    What can explicitly not be concluded from this study?

    Not representative for Egypt.

    Scientific details →

  • Egyptian farms: good hygiene, not housing type alone, makes eggs cleaner

    Hafez E et al.. Vet Ital 2025 · PMID 40232862 · DOI 10.12834/VetIt.3466.29418.2
    Cross-sectional studyindependent cross-checkabstract checked

    Closed battery-cage farms with strong biosecurity had fewer bacteria on eggs than open deep-litter and backyard systems.

    Egypt: closed battery farms with high biosecurity had less contamination than deep-litter/backyard systems.

    Does the study support the specific claim? No · Methodological quality: low · Certainty of evidence: see overall assessment of the claim

    Original publication · Scientific details

    Study explained simply
    What did the researchers want to find out?

    Compare egg hygiene across Egyptian farms.

    How was the study done?

    Farm sampling.

    How many people, animals or samples were studied?

    70 samples from 7 farms.

    What was actually found?

    High-biosecurity cage farms had cleaner eggs.

    How large was the observed effect?

    Not reported in abstract.

    What do the results mean in everyday life?

    In Egypt, backyard eggs are not automatically safer.

    What are the study's limitations?

    Very small study.

    What does it say about Elawady's specific claim?

    Contradicts a simple 'cages = more Salmonella' rule in Egypt.

    Do the results apply to Germany and Europe?

    Egypt-specific.

    What can explicitly not be concluded from this study?

    It cannot give national prevalence.

    Scientific details →

  • Chile: Salmonella found only in cage-free eggs

    Solís D et al.. Foods 2023 · PMID 38231772 · DOI 10.3390/foods12234300
    Cross-sectional studyindependent cross-checkabstract checked

    Salmonella Enteritidis was found in 2 of 186 cage-free egg samples and none of 240 conventional samples.

    S. Enteritidis found only in cage-free eggs (2/186) vs 0/240 conventional (Chile).

    Does the study support the specific claim? No · 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?

    Compare Salmonella in eggs by production system.

    How was the study done?

    Egg sampling and sequencing.

    How many people, animals or samples were studied?

    426 samples.

    What was actually found?

    Only cage-free eggs positive (1.1%).

    How large was the observed effect?

    1.1% vs 0%.

    What do the results mean in everyday life?

    Cage-free or free-range eggs also need safe handling and cooking.

    What are the study's limitations?

    Very few positives.

    What does it say about Elawady's specific claim?

    Contradicts the simple cage rule.

    Do the results apply to Germany and Europe?

    Moderate.

    What can explicitly not be concluded from this study?

    It cannot show which system is safer overall.

    Scientific details →

Studies with mixed or unclear results (2)

  • EU rules for laying hens

    European Commission. EU legislation / EC web page 1999
    Guideline / position statementindependent cross-checkfull text checked

    The EU banned barren battery cages in 2012; enriched cages and cage-free systems remain.

    Salmonella is far more common in caged egg production than in cage-free systems (44% vs 3.2%).

    Does the study support the specific claim? Unclear · Methodological quality: not applicable · Certainty of evidence: see overall assessment of the claim

    Original publication · Scientific details

    Study explained simply
    What did the researchers want to find out?

    Minimum welfare standards for laying hens

    How was the study done?

    EU directive (official summary page)

    How many people, animals or samples were studied?

    Not applicable; EU laying hens

    What was actually found?

    Non-enriched cage systems prohibited since 1 January 2012; enriched cages require at least 750 cm2 cage area per hen; alternative systems max 9 hens/m2 usable area; all hens need nest, perching, litter, access to feed and water.

    How large was the observed effect?

    Not applicable

    What do the results mean in everyday life?

    EU eggs come from enriched cages, barns, free-range or organic farms.

    What are the study's limitations?

    Enriched cages still permitted

    What does it say about Elawady's specific claim?

    Context for the cage claim.

    Do the results apply to Germany and Europe?

    Directly EU.

    What can explicitly not be concluded from this study?

    Not a health study.

    Scientific details →

  • Salmonella found inside some Egyptian market eggs

    Abou Elez RMM et al.. Animals (Basel) 2021 · PMID 34944331 · DOI 10.3390/ani11123554
    Cross-sectional studyindependent cross-checkfull text checked

    3.6% of retail table egg contents in Sharkia carried Salmonella, often drug-resistant.

    Egyptian retail eggs: Salmonella in 3.6% of egg contents; housing not studied; supports thorough cooking.

    Does the study support the specific claim? Unclear · Methodological quality: low · Certainty of evidence: see overall assessment of the claim

    Original publication · Scientific details

    Study explained simply
    What did the researchers want to find out?

    Measure Salmonella in hens, eggs and people in Egypt.

    How was the study done?

    Cross-sectional sampling.

    How many people, animals or samples were studied?

    431 samples incl. 165 eggs.

    What was actually found?

    Salmonella present in eggs and hens; high resistance.

    How large was the observed effect?

    Egg contents 3.6%.

    What do the results mean in everyday life?

    In Egypt, eggs should be cooked well, especially for vulnerable people.

    What are the study's limitations?

    Small regional sample.

    What does it say about Elawady's specific claim?

    Does not test cages vs cage-free.

    Do the results apply to Germany and Europe?

    Low.

    What can explicitly not be concluded from this study?

    It cannot compare housing systems.

    Scientific details →

Regional context

Germany / EU

Directive 1999/74/EC banned unenriched cages from 1 January 2012 (enriched cages >= 750 cm2 per hen still allowed; Germany has its own stricter national rules, not reviewed here). Salmonella reduction targets for laying-hen flocks apply; in 2024 the EU flock prevalence of target serovars in adult laying hens was 1.6%.

Egypt

Egyptian data are limited. In Sharkia governorate, Salmonella was isolated from 3.6% of retail table egg contents, often multidrug-resistant (I-EGG-126). A small study of seven Egyptian layer farms found that closed battery (cage) farms with high biosecurity had less bacterial contamination of eggs than open deep-litter and backyard systems (I-EGG-125), i.e. the opposite of a simple 'cages = more Salmonella' rule. In the UAE, shell contamination was found only in cage-laid retail eggs (11.6% vs 0%), with clean contents (I-EGG-124). Production systems and control programmes differ from the EU.

What applies in my country?

General scientific assessment

Mostly true Cage systems are associated with more Salmonella on farms, but contamination of eggs on sale in the EU is rare.

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.)
  • Animal husbandry and feed
  • Controls, imports, recalls, labelling

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.

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References

  1. Prevalence and Genetic Analysis of Salmonella enterica from a Cross-Sectional Survey of the New Zealand Egg Production Environment.. Kingsbury JM et al.. J Food Prot 2019 · PMID 31742446 · DOI 10.4315/0362-028X.JFP-19-159
  2. Salmonella control in poultry flocks and its public health impact.. EFSA BIOHAZ Panel. EFSA J 2019 · PMID 32626222 · DOI 10.2903/j.efsa.2019.5596
  3. Risk Factors Associated With Salmonella in Laying Hen Farms: Systematic Review of Observational Studies.. Denagamage T et al.. Avian Dis 2015 · PMID 26473681 · DOI 10.1637/10997-120214-Reg
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