Products & safety
Aflatoxins: B1 and M1, food and feed, liver-cancer evidence, sampling and action levels
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Aflatoxins are a family of fungal toxins that can contaminate crops and reach people through food, with additional occupational dust pathways. They are a recognized liver-cancer hazard. Useful interpretation starts by identifying the form, food and exposure pattern, rather than treating every mold finding as equivalent.[1]
Aflatoxins are one family of mycotoxins
Aflatoxins are toxic chemicals made by certain Aspergillus fungi, not a synonym for all molds or all mycotoxins. Susceptible crops include corn, peanuts and tree nuts; contamination can develop in the field, at harvest or during storage. People can ingest contaminated food or, in agricultural work, inhale contaminated dust. These routes require different controls. A food category identifies a possible pathway, not a measured concentration in every package or a diagnosis in everyone who eats it.[1]
B1, total aflatoxins and M1 are different results
Aflatoxin B1 is an important common form and a potent genotoxic carcinogenic hazard. M1 is a metabolite of B1 that can be present in milk after animals consume contaminated feed. A report for total aflatoxins needs its definition: the usual crop sum includes B1, B2, G1 and G2. A milk M1 test is separate. Adding the names clarifies both what was measured and which food-specific assessment or regulatory comparison might apply.[2]
Acute toxicity and lifetime exposure are different
FDA/USDA’s 2026 agreement describes acute toxicity at sufficient amounts, alongside carcinogenicity. A large exposure and repeated smaller exposure are different clinical events. Exposure estimation needs concentration, amount consumed and duration, with other sources considered. The acute hazard does not establish that one trace detection causes liver failure. Lack of immediate symptoms does not show that chronic contamination is acceptable. This overview supplies no personal treatment threshold.[7]
A small sample can miss a contaminated pocket
A 2018 peanut study explains uneven kernel-to-kernel contamination and experimentally compares sample-preparation approaches. Grinding and mixing affect how well a smaller test portion represents the larger sample. The study involved a limited contaminated lot, so it does not rank all laboratories or brands. Its practical lesson is that sampling, preparation and instrument analysis all matter. An impressive detection limit cannot compensate for an unrepresentative handful of nuts, and a single negative package cannot certify every package.[9]
Evidence & uncertainty
This explanation uses official assessments, a current agency agreement and selected analytical research. Human cancer evidence supports contamination prevention, but neither a hazard classification nor a product test predicts an individual outcome. Sampling and dose assumptions remain visible.[3]
Selected-source overview · Independent review pendingPublished questions
Are aflatoxins the same as all mycotoxins?
Selected-source overview · Independent review pending. Read the evidence context.
No. They are one Aspergillus-associated family. Other fungal toxins have different chemistry, food contexts and evidence, so an aflatoxin-only test is not comprehensive.[1]
Evidence behind this answer
- Aflatoxins: Cancer-Causing Substances
agency guidance or assessment · 2024
Original official page and selected relevant passages inspected; no independent expert review · Definitions, agricultural and dietary/dust routes, liver-cancer association, exposure reduction
This answer summarizes selected sources. An independent appraisal of the complete evidence has not been completed.
Is aflatoxin M1 the same test as crop total aflatoxins?
Selected-source overview · Independent review pending. Read the evidence context.
No. EFSA describes M1 as a B1 metabolite that can reach milk through contaminated feed. It needs a separately specified analyte and food comparison.[2]
Evidence behind this answer
- Aflatoxins in food
agency guidance or assessment · Date not stated
Original official page and selected relevant passages inspected; no independent expert review · B1 prominence; M1 metabolite in milk from contaminated feed; low-exposure goal
This answer summarizes selected sources. An independent appraisal of the complete evidence has not been completed.
Does a negative raw-peanut certificate mean zero aflatoxin?
Selected-source overview · Independent review pending. Read the evidence context.
No. The 2026 FDA/USDA agreement defines negative in that program as total aflatoxins at or below 15 ppb. The word has a program-specific meaning.[7]
Evidence behind this answer
- MOU 225-26-004
agency guidance or assessment · 2026
Original official page and selected relevant passages inspected; no independent expert review · Sections III and IV: acute toxicity; raw-peanut testing; negative certificate means <=15 ppb; program differences
This answer summarizes selected sources. An independent appraisal of the complete evidence has not been completed.
Can one small sample certify a whole lot?
Selected-source overview · Independent review pending. Read the evidence context.
Not with certainty. Peanut research shows heterogeneous contamination and preparation-related variation. The collection and mixing plan matters alongside the analytical method.[9]
Evidence behind this answer
- Sample Preparation and Analytical Considerations for the US Aflatoxin Sampling Program for Shelled Peanuts
primary analytical research · 2018
Original research article abstract, sampling description and selected results inspected; limited-lot sampling study, not a survey of all current peanut products · Abstract, introduction and experiments: heterogeneous kernels, milling and subsampling variation; limited contaminated-lot study
This answer summarizes selected sources. An independent appraisal of the complete evidence has not been completed.
What does an approved laboratory program add?
Selected-source overview · Independent review pending. Read the evidence context.
USDA describes proficiency samples and annual on-site reviews in its commodity programs. Those quality requirements support analytical performance; they do not eliminate sampling uncertainty.[8]
Evidence behind this answer
- Aflatoxin: Almond, Peanut and Pistachio Approvals
agency guidance or assessment · Date not stated
Original official page and selected relevant passages inspected; no independent expert review · Commodity laboratory programs, proficiency checks and annual on-site reviews
This answer summarizes selected sources. An independent appraisal of the complete evidence has not been completed.
Does hepatitis B matter for aflatoxin risk?
Selected-source overview · Independent review pending. Read the evidence context.
Yes. JECFA identifies hepatitis B infection as affecting liver-cancer potency. This does not mean aflatoxin exposure is harmless without hepatitis B.[5]
Evidence behind this answer
- Aflatoxins: JECFA database assessment
agency guidance or assessment · 2016
Original official page and selected relevant passages inspected; no independent expert review · 83rd-meeting conclusions: hepatitis B and aflatoxin potency; aflatoxin/fumonisin mixture evidence
This answer summarizes selected sources. An independent appraisal of the complete evidence has not been completed.
Are all aflatoxin forms known to be equally potent?
Selected-source overview · Independent review pending. Read the evidence context.
No. EFSA used some equal-potency assumptions because evidence was insufficient, while assigning M1 a different factor. Assumptions and measured findings should remain distinct.[4]
Evidence behind this answer
- Risk assessment of aflatoxins in food
agency guidance or assessment · 2020
Original agency-assessment abstract indexed by PubMed inspected; complete assessment and underlying studies not independently appraised · Original assessment abstract: five forms; occurrence data; margin of exposure; potency assumptions
This answer summarizes selected sources. An independent appraisal of the complete evidence has not been completed.
The liver-cancer evidence is more than a mechanism
NTP lists aflatoxins as known human carcinogens, drawing on human studies as well as laboratory evidence. Hepatitis B complicates interpretation because it independently causes liver cancer and can modify risk. Studies accounting for infection still found aflatoxin associations. This supports prevention while preserving the distinction between a population hazard and an individual's cancer probability. The profile's historical studies are not a contemporary estimate of contamination in a particular supermarket product, and they cannot assign the cause of one person's tumor.[3]
Risk models retain important assumptions
EFSA's 2020 assessment considered five forms and large occurrence datasets, then used exposure estimates and margin-of-exposure methods. It used a lower potency factor for M1 relative to B1, while assuming equal potency for some other forms because data were insufficient. The assumption is not proof that their toxicities are identical. Its conclusion of concern is an assessment across dietary patterns, not a calculated cancer probability from one jar. Younger groups and repeatedly consumed foods require appropriate exposure context.[4]
An action level is not a harmless intake allowance
FDA's 2021 human-food policy discusses total aflatoxins above 20 micrograms per kilogram, equivalent to 20 parts per billion, in its adulteration and enforcement context. Separate nut guides and sampling requirements also apply. The guidance is not itself a universal statutory limit or a daily intake allowance, and it calls for reduction to the lowest attainable levels. Its food concentration should not be compared directly with a blood biomarker or used to declare every lower detection risk-free.[6]
Hepatitis interactions and toxin mixtures differ
JECFA identifies hepatitis B as an important contributor to aflatoxin-related liver-cancer potency. It also considered co-exposure with fumonisins: laboratory evidence raised concern, but human data were insufficient to establish the proposed combined disease effects. Those are different evidential situations. Reducing both contaminants is sensible risk management, yet a multi-toxin detection does not establish a measured synergy in the consumer. Prevention should address contaminated food and appropriate liver-health care without claiming that one cancels the other.[5]
References
- Aflatoxins: Cancer-Causing Substances
Agency guidance or assessment
US National Cancer Institute · Content/publication date: 2024
Accessed: 2026-10-13 UTC · Original official page and selected relevant passages inspected; no independent expert review
Cited sections: Definitions, agricultural and dietary/dust routes, liver-cancer association, exposure reductionPublication or content date is distinct from access date; no claim of continuous monitoring.
- Aflatoxins in food
Agency guidance or assessment
EFSA · Content/publication date: not stated
Accessed: 2026-10-13 UTC · Original official page and selected relevant passages inspected; no independent expert review
Cited sections: B1 prominence; M1 metabolite in milk from contaminated feed; low-exposure goalPublication or content date is distinct from access date; no claim of continuous monitoring.
- Aflatoxins: Report on Carcinogens, Fifteenth Edition
Agency guidance or assessment
NTP/NIEHS · Content/publication date: 2021
Accessed: 2026-10-13 UTC · Original official three-page profile, selected human-evidence passages inspected; original cohort datasets not reanalyzed
Cited sections: Page 1: human cancer evidence, hepatitis-B confounding and cohort biomarker findingsPublication or content date is distinct from access date; no claim of continuous monitoring.
- Risk assessment of aflatoxins in food
Agency guidance or assessment
EFSA CONTAM Panel · Content/publication date: 2020
Accessed: 2026-10-13 UTC · Original agency-assessment abstract indexed by PubMed inspected; complete assessment and underlying studies not independently appraised
Cited sections: Original assessment abstract: five forms; occurrence data; margin of exposure; potency assumptionsPublication or content date is distinct from access date; no claim of continuous monitoring.
- Aflatoxins: JECFA database assessment
Agency guidance or assessment
WHO/FAO JECFA · Content/publication date: 2016
Accessed: 2026-10-13 UTC · Original official page and selected relevant passages inspected; no independent expert review
Cited sections: 83rd-meeting conclusions: hepatitis B and aflatoxin potency; aflatoxin/fumonisin mixture evidencePublication or content date is distinct from access date; no claim of continuous monitoring.
- CPG 555.400: Aflatoxins in Human Food
Agency guidance or assessment
US FDA · Content/publication date: 2021
Accessed: 2026-10-13 UTC · Original FDA compliance guide PDF background, policy and action-guidance sections inspected; nonbinding guidance distinguished from law
Cited sections: Pages 2-3: lowest attainable exposure, total B1/B2/G1/G2, 20-ppb policy and separate nut guidesPublication or content date is distinct from access date; no claim of continuous monitoring.
- MOU 225-26-004
Agency guidance or assessment
US FDA and USDA/AMS · Content/publication date: 2026
Accessed: 2026-10-13 UTC · Original official page and selected relevant passages inspected; no independent expert review
Cited sections: Sections III and IV: acute toxicity; raw-peanut testing; negative certificate means <=15 ppb; program differencesPublication or content date is distinct from access date; no claim of continuous monitoring.
- Aflatoxin: Almond, Peanut and Pistachio Approvals
Agency guidance or assessment
USDA Agricultural Marketing Service · Content/publication date: not stated
Accessed: 2026-10-13 UTC · Original official page and selected relevant passages inspected; no independent expert review
Cited sections: Commodity laboratory programs, proficiency checks and annual on-site reviewsPublication or content date is distinct from access date; no claim of continuous monitoring.
- Sample Preparation and Analytical Considerations for the US Aflatoxin Sampling Program for Shelled Peanuts
Primary analytical research
Davis JP, Jackson MD, Leek JM, Samadpour M / Peanut Science · Content/publication date: 2018
Accessed: 2026-10-13 UTC · Original research article abstract, sampling description and selected results inspected; limited-lot sampling study, not a survey of all current peanut products
Cited sections: Abstract, introduction and experiments: heterogeneous kernels, milling and subsampling variation; limited contaminated-lot studyPublication or content date is distinct from access date; no claim of continuous monitoring.
Scope & review
- Population
- General readers; vulnerable populations and source-specific exposure settings are distinguished
- Exposure or intervention
- Aflatoxins
- Comparison
- Chemical forms, exposure routes, source-specific populations and jurisdiction-specific rules
- Outcomes
- Definitions, categories, exposure interpretation, practical questions and uncertainty
- Timeframe
- Selected historical and current sources checked 2026-10-13; publication dates are recorded separately
- Jurisdiction
- US and explicitly identified international guidance; local requirements differ
Bounded selected-source educational explanation. Agency assessments and editorial interpretation 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 explainer with exposure distinctions, source-linked questions and uncertainty.
What this article still leaves open
- No complete current commodity-specific legal table, brand survey or personal cancer-risk calculation is supplied.
- Translation of mixture experiments and species-specific potency assumptions needs further appraisal.
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