Products & safety
Ochratoxin A: storage fungi, coffee and cereals, kidney hazard and changing risk assessments
On this page
Ochratoxin A, or OTA, is a toxin produced by certain Aspergillus and Penicillium fungi. Animal studies show kidney toxicity and kidney tumors. Human-risk interpretation requires food exposure and evidence limits; presence of a toxin is not a diagnosis.[1]
Storage conditions influence contamination
OTA often forms during storage, although field contamination occurs. Grain-based staples dominate Canadian dietary exposure. Other commodities can contain it. A possible-source list does not establish a high concentration in one package. Exposure combines concentration and amount eaten; a food category or organic label cannot supply that measurement.[2]
Normal appearance does not measure a chemical toxin
The Canadian Grain Commission explains that OTA-producing fungi can develop in grain when moisture and temperature exceed suitable storage conditions. The toxin and fungus may not cause visible damage. Therefore visual inspection alone cannot certify a grain lot as toxin-free. Prevention focuses on keeping grain cool and dry and appropriate aeration. The moisture conditions for safe storage vary by crop; a room humidity percentage and a grain moisture-content percentage also measure different things.[3]
Roasting can reduce OTA without guaranteeing its absence
An original 2003 experiment studied four naturally contaminated green-coffee samples under light, medium and dark roasting conditions. Reductions depended on severity and initial contamination; conditions suitable for a typical Italian espresso roast reduced OTA by more than 90 percent in those samples. That is a process finding, not a guarantee for every brand, bean lot or brewed cup. The investigators also found that off-flavors and visible defects did not directly track the toxin level.[4]
Loss of the parent chemical is not the whole toxicology question
A separate study identified roasting-related OTA degradation products and tested cytotoxicity in cell culture. It found a diastereomer in market coffee samples and reported that tested degradation products were less cytotoxic than OTA in those experiments. This distinguishes chemical transformation from complete removal and a cell assay from a human health outcome. It does not establish that home roasting is a validated decontamination treatment or that every transformation product has been comprehensively assessed.[5]
Evidence & uncertainty
This page compares selected assessments rather than applying an atlas certainty grade. EFSA changed its approach in 2020; Health Canada's newer assessment reached low concern for estimated Canadian dietary exposure. Different populations, data and assessment assumptions matter when comparing those conclusions.[2]
Selected-source overview · Independent review pendingPublished questions
Can good-looking grain guarantee no OTA?
Selected-source overview · Independent review pending. Read the evidence context.
No. The Canadian Grain Commission says OTA and the relevant fungus can be present without visible damage. Suitable chemical testing addresses the toxin.[3]
Evidence behind this answer
- Prevent ochratoxin A in stored grain
agency guidance or assessment · 2026
Original official page and selected relevant passages inspected · Storage controls, grain moisture and lack of visible damage
This answer summarizes selected sources. An independent appraisal of the complete evidence has not been completed.
Does roasting always remove every trace from coffee?
Selected-source overview · Independent review pending. Read the evidence context.
No. The experiment found reductions under specified conditions, not universal elimination. Initial contamination and roast conditions affected the result.[4]
Evidence behind this answer
- Influence of roasting levels on ochratoxin A content in coffee
original processing experiment · 2003
Original research abstract inspected; full study not inspected · Abstract: four contaminated samples, process-dependent reductions and visible defects
This answer summarizes selected sources. An independent appraisal of the complete evidence has not been completed.
Is EFSA's 2006 weekly intake still its latest approach?
Selected-source overview · Independent review pending. Read the evidence context.
No. EFSA's 2020 update moved to a margin-of-exposure approach. The old value needs its historical date and context.[7]
Evidence behind this answer
- Ochratoxin A in food: public health risks assessed
agency guidance or assessment · 2020
Original official page and selected relevant passages inspected · 2020 new evidence and margin-of-exposure approach
This answer summarizes selected sources. An independent appraisal of the complete evidence has not been completed.
Has Canada currently adopted mandatory maximum OTA levels?
Selected-source overview · Independent review pending. Read the evidence context.
The checked Health Canada page says its updated risk assessment finds no need for regulatory maximum levels currently. Monitoring and surveillance continue.[2]
Evidence behind this answer
- Ochratoxin A in foods: health risk assessment and management approach
agency guidance or assessment · Date not stated
Original official page and selected relevant passages inspected · Updated 2025 HRA, exposure contributors, low concern and no ML deemed necessary
This answer summarizes selected sources. An independent appraisal of the complete evidence has not been completed.
Does a less-toxic roasting product in cells prove safety in people?
Selected-source overview · Independent review pending. Read the evidence context.
No. A cell-culture comparison informs mechanism and relative activity under test conditions; it is not a clinical outcome or complete exposure assessment.[5]
Evidence behind this answer
- Identification and in vitro cytotoxicity of OTA degradation products formed during coffee roasting
original processing and cell culture experiment · 2008
Indexed original research abstract excerpts inspected; direct retrieval was empty · Indexed abstract: diastereomer detection and cell-culture toxicity comparison
This answer summarizes selected sources. An independent appraisal of the complete evidence has not been completed.
What prevention targets the source?
Selected-source overview · Independent review pending. Read the evidence context.
JECFA emphasizes good harvest practices, rapid drying and keeping commodities dry in storage and transport, with controls adapted to the crop and fungus.[9]
Evidence behind this answer
- Ochratoxin A addendum, Safety evaluation of certain food additives and contaminants
agency technical monograph · 2008
Selected original technical-monograph sections inspected; no independent comprehensive review · Section 7, pages 46–47: prevention and commodity-specific storage controls
This answer summarizes selected sources. An independent appraisal of the complete evidence has not been completed.
The old weekly value should not be treated as current EFSA advice
In 2006 EFSA derived a tolerable weekly intake of 120 nanograms per kilogram body weight, emphasizing dose-related kidney effects in animals. Its 2020 update used a margin-of-exposure approach following new evidence and uncertainty about genotoxic mechanisms. An old numeric value can remain visible on a historical page without remaining the appropriate current framework. A margin of exposure compares estimated intake with toxicological reference points; it is neither a product concentration limit nor a forecast of how many individuals will develop disease.[6][7]
Updated Canadian exposure data changed the management context
Health Canada's updated 2025 assessment incorporated newer occurrence, consumption and hazard data and found dietary exposure somewhat lower than its 2009 estimates. Its January 2026 page describes exposure as of low concern and says regulatory maximum levels are not considered necessary currently. That conclusion applies to the Canadian exposure context and assessment. It does not negate OTA's animal hazard or prove that a highly contaminated batch elsewhere is acceptable. Monitoring continues.[2]
Selected-food surveys have their own sampling frame
CFIA's multi-year selected-food report covers commodities including coffee, cocoa, cereals, dried fruit and spices. A targeted chemistry survey asks whether the sampled products contain the analyte and assesses findings within a defined program. Its historical discussion of proposed Canadian levels must be read alongside the newer Health Canada decision. Survey percentages and averages depend on food selection, years and analytical sensitivity; they cannot independently rank an untested purchase or establish a nationwide absence claim.[8]
Food-system controls are more concrete than a purity slogan
JECFA's OTA addendum discusses crop handling, rapid drying and maintenance of dry conditions through storage and transport, with commodity-specific differences. These are preventive controls, rather than evidence that any cooking step erases existing contamination. A useful supplier report names the toxin, sampling plan, units, detection limits and the lot. The chemical data still need intake interpretation. This page does not diagnose kidney disease, prescribe a binder or certify a coffee marketed as mold-free.[9]
References
- Risk assessment of ochratoxin A in food
Agency scientific opinion
EFSA · Content/publication date: 2020
Accessed: 2026-10-13 UTC · Original official page and selected relevant passages inspected
Cited sections: Abstract: fungi, animal kidney toxicity/tumors and genotoxic uncertaintySelected-source access only; check date is distinct from publication date. No independent expert review.
- Ochratoxin A in foods: health risk assessment and management approach
Agency guidance or assessment
Health Canada · Content/publication date: not stated
Accessed: 2026-10-13 UTC · Original official page and selected relevant passages inspected
Cited sections: Updated 2025 HRA, exposure contributors, low concern and no ML deemed necessarySelected-source access only; check date is distinct from publication date. No independent expert review.
- Prevent ochratoxin A in stored grain
Agency guidance or assessment
Canadian Grain Commission · Content/publication date: 2026
Accessed: 2026-10-13 UTC · Original official page and selected relevant passages inspected
Cited sections: Storage controls, grain moisture and lack of visible damageSelected-source access only; check date is distinct from publication date. No independent expert review.
- Influence of roasting levels on ochratoxin A content in coffee
Original processing experiment
Romani et al. · Content/publication date: 2003
Accessed: 2026-10-13 UTC · Original research abstract inspected; full study not inspected
Cited sections: Abstract: four contaminated samples, process-dependent reductions and visible defectsSelected-source access only; check date is distinct from publication date. No independent expert review.
- Identification and in vitro cytotoxicity of OTA degradation products formed during coffee roasting
Original processing and cell culture experiment
Cramer et al. · Content/publication date: 2008
Accessed: 2026-10-13 UTC · Indexed original research abstract excerpts inspected; direct retrieval was empty
Cited sections: Indexed abstract: diastereomer detection and cell-culture toxicity comparisonSelected-source access only; check date is distinct from publication date. No independent expert review.
- EFSA evaluates ochratoxin A and derives a Tolerable Weekly Intake
Agency guidance or assessment
EFSA · Content/publication date: 2006
Accessed: 2026-10-13 UTC · Original official page and selected relevant passages inspected
Cited sections: Historical 2006 TWI and dose-duration kidney effectsSelected-source access only; check date is distinct from publication date. No independent expert review.
- Ochratoxin A in food: public health risks assessed
Agency guidance or assessment
EFSA · Content/publication date: 2020
Accessed: 2026-10-13 UTC · Original official page and selected relevant passages inspected
Cited sections: 2020 new evidence and margin-of-exposure approachSelected-source access only; check date is distinct from publication date. No independent expert review.
- Ochratoxin A in selected foods, 2012–2018 and 2019–2022
Agency food occurrence survey
CFIA · Content/publication date: not stated
Accessed: 2026-10-13 UTC · Original official page and selected relevant passages inspected
Cited sections: Survey scope, commodity categories and historical proposed-level contextSelected-source access only; check date is distinct from publication date. No independent expert review.
- Ochratoxin A addendum, Safety evaluation of certain food additives and contaminants
Agency technical monograph
FAO/WHO JECFA · Content/publication date: 2008
Accessed: 2026-10-13 UTC · Selected original technical-monograph sections inspected; no independent comprehensive review
Cited sections: Section 7, pages 46–47: prevention and commodity-specific storage controlsSelected-source access only; check date is distinct from publication date. No independent expert review.
Scope & review
- Population
- General readers; food exposure, occupational settings and vulnerable populations are distinguished where relevant
- Exposure or intervention
- Ochratoxin A
- Comparison
- Chemical forms, routes, dose and duration; health guidance versus product limits
- Outcomes
- Identity, everyday sources, evidence, practical interpretation and uncertainty
- Timeframe
- Selected sources checked 2026-10-13; historical evidence is dated separately
- Jurisdiction
- US and explicitly identified European or international sources; local rules differ
Bounded selected-source educational explanation. Official assessments, original studies and editorial inference are distinguished. No exhaustive search, independent systematic synthesis or qualified medical review.
Sources checked on their individual access dates. Selected sources were checked; ongoing surveillance and qualified review have separate statuses on the coverage page.
Revision history
- 2026-10-13 UTC: Added definition-first explanation, categories, practical questions and source-linked uncertainty.
What this article still leaves open
- No product-specific safety certificate or individualized exposure diagnosis is provided.
- Jurisdiction-specific implementation, sampling methods and newly published evidence require separate assessment.
Suggest a correction
Submit a content correction to the editorial queue, or download a local note. Leave out personal medical details. Submitted text is stored privately with a browser receipt session and is visible to this browser and the editor. Clearing cookies removes access to your submission history. This is not an account or a medical service.
Your submitted corrections for this article
Explore the topic map
Browse the health domains connected to this article. The map also identifies topics whose articles remain unwritten.