Contaminants in cocoa and chocolate

Lead, nickel, mould toxins, combustion products, acrylamide, pesticide residues and mineral oil: where each gets in, what process does to it, what the law says and how big the exposure is. Cadmium has a page of its own.

8 contaminantsStudies and legal textsDetected is not dangerous

Reading a contaminant finding

Found is not the same as harmful. Modern methods detect a few parts per billion. Several surveys here found a contaminant in every sample, at levels below every limit that exists.
Three of these sit in the shell. Lead, ochratoxin A and at least one pesticide are concentrated on the outside of the bean, so removing the shell removes most of them. Products made from shell are a different matter.
Benchmarks differ by orders of magnitude. The same set of products can be mostly over one and almost all under another. Always ask which.

Nothing here is medical advice. For cadmium, see cadmium in cacao and chocolate.

Lead

Lead differs from cadmium in one decisive way: the tree does not put it in the bean. It arrives on the outside, after harvest.

Source and entry: isotope and rare-earth measurements indicate that lead is acquired after harvest and concentrated in the shell, apparently while beans dry on bare soil. The same study found no measurable addition during transport of beans or manufacture of chocolate. (Manton 2010)
Process: because it sits on the shell, removing the shell removes much of it. Along three production lines the fall in lead varied from nothing to all of it, with winnowing and conching the steps that counted. Like cadmium it stays with the cocoa solids when liquor is pressed. (Kruszewski et al. 2018; Mounicou et al. 2003)
In products: in American retail cocoa and chocolate, lead ranged from undetectable to 0.38 mg/kg and rose with cocoa percentage. (Abt et al. 2018)
Regulation, United States: the regulator recommends that lead in candy likely to be eaten often by small children should not exceed 0.1 parts per million. That is guidance, and about candy in general. Its reference levels for lead from the whole diet are 2.2 micrograms a day for children and 8.8 for women of childbearing age. (source 1; source 2)
Regulation, California: the warning threshold is 0.5 micrograms a day, set a thousandfold below an observed no-effect level, and a 2018 settlement turned it into warning triggers for chocolate of 0.100 to 0.225 parts per million by cacao content. (source 3; source 4; source 5)
Regulation, European Union: no maximum level for lead in chocolate was found in the texts read.
Risk context: the American regulator says no safe level of lead exposure has been identified, and the European assessor found no evidence of a threshold for its critical effects. That is why reference levels are set low, and why they are not thresholds of harm. (source 2; source 6)
Exposure: the choice of benchmark decides the headline. Of 72 American products, 43% exceeded the Californian level per serving and 97% were below the federal reference level. A model of lead exposure in the United States put chocolate bars at under 1% of typical total intake, with soil and dust accounting for most of the variation in young children. (Hands et al. 2024; Thornton et al. 2026)

Not shown: That lead is added in the factory. The one study that looked found no measurable addition there.

Not shown: How much of the lead on the shell reaches finished chocolate.

Not shown: That a product exceeding the Californian level is harmful. It is a threshold for a notice.

Nickel

Source: nickel was the most abundant of three metals measured in raw cocoa on three production lines, at up to 12.1 mg/kg, falling to at most 4.5 mg/kg in chocolate. (Kruszewski et al. 2018)
Regulation: the European Union set maximum levels for nickel in chocolate for the first time from 1 July 2025: 2.5 mg/kg for milk chocolate with less than 30% cocoa solids, 7.0 mg/kg for other milk chocolate and for chocolate, and 15 mg/kg for cocoa powder sold to consumers. (source 7)
Exposure and risk: the European assessor set a tolerable daily intake of 13 micrograms per kg of body weight in 2020, found that high consumers among toddlers and other children generally exceeded it while adolescents and adults did not, and noted that the high average for confectionery was driven mainly by chocolate and cocoa products. (source 8)

Not shown: Where the nickel comes from, or how it varies by region. No soil or origin study of nickel in cacao was read.

Not shown: Levels in chocolate on sale. One study of three factories is all that was read.

Ochratoxin A

A toxin made by moulds that grow on beans during fermentation, drying and storage.

Where it sits: in the shell. Shelling by hand removed more than 95% from most contaminated samples; in deliberately mouldy Ivorian beans 93% was in the shell; and the international code of practice says the same. (Amézqueta et al. 2005; Manda et al. 2009; source 9)
Process: shell removal is the step that matters. One experiment lost 93.6% between bean and chocolate, another about 91%. What remains stays with the cocoa solids, so cocoa powder and cake carry the most and cocoa butter the least. (Copetti et al. 2013; Manda et al. 2009; source 9)
In products: a Canadian survey found it in every one of 32 cocoa powders and 28 chocolates, at 0.25 to 7.8 and 0.05 to 1.4 parts per billion. (Turcotte and Scott 2011)
Regulation: the European Union sets 3.0 micrograms per kg for cocoa powder and no level for cocoa beans or chocolate. (source 10)
Risk context: in 2020 the European assessor judged it inappropriate to set a tolerable intake at all and used a margin-of-exposure approach, describing its own uncertainty as high and saying the risk may be overestimated. Its earlier tolerable weekly intake is no longer considered valid. (source 11; source 12)

Not shown: How often beans are contaminated, or where. The process studies used beans chosen or made to be contaminated.

Not shown: That detection in every sample means a problem. The Canadian levels were low, and detection reflects the sensitivity of the method.

Aflatoxins

Source: the moulds that make aflatoxin were common on Brazilian cocoa and increased during drying and storage, yet only low levels of the toxin were found, which the authors take to mean something in the bean limits its accumulation. (Copetti et al. 2011)
In products: in Spain aflatoxins were detected in 51.4% of cocoa powders and 28.8% of chocolate bars, more often in dark than in milk, with the highest values around 3 micrograms per kg in cocoa powder. (Concellón et al. 2026)
Exposure: the Spanish study calculated margins of exposure below the conventional benchmark for adolescents, children and toddlers at average cocoa powder consumption. (Concellón et al. 2026)
Regulation: no maximum level for aflatoxins in cocoa or chocolate was found in the European regulation read.

Not shown: Harm. A margin of exposure below the benchmark is a flag for a substance that damages DNA, not a measured effect, and the same authors describe chocolate as a minor contributor.

Not shown: Occurrence outside Spain and Brazil.

Polycyclic aromatic hydrocarbons

Combustion products. They are usually said to reach cocoa from smoke when beans are dried over fires.

Process: roasting at 160°C formed light compounds of this family and not the heavy ones the law regulates; the sum of the four regulated compounds stayed well below the maximum. (Ciecierska 2020)
Regulation: the European Union limits benzo(a)pyrene to 5.0 micrograms per kg of fat, and the sum of four compounds to 30.0, in cocoa beans and derived products. (source 10)
Cocoa fibre, which is made from the shell, has its own stricter figures on a whole-product basis, and the regulation explains that shell-derived products contain more. (source 10)

Not shown: That smoke drying contaminates cocoa. It is the usual explanation and no primary study of smoke-dried beans was found; the one study read did not examine them.

Acrylamide

Formed when foods containing sugars and the amino acid asparagine are heated.

Process: roasting raised acrylamide in cocoa beans two to three fold in a study of three factories, whose results also suggested some formation during wet conching. (Kruszewski and Obiedziński 2020)
In products: across 363 samples from the German market it ranged from unquantifiable to 490 micrograms per kg, averaging 190 in semi-finished cocoa and 50 in finished cocoa and chocolate products. All were well below Germany's general signal value of 1,000. (Raters and Matissek 2018)
Regulation: no European benchmark or maximum level specific to cocoa or chocolate was read.

Not shown: That alkalisation changes acrylamide. It is sometimes claimed and no study was found.

Not shown: Any risk estimate for acrylamide from chocolate. None was read.

Pesticide residues

Three different questions are asked of a residue, and they have different answers. Is it over the legal limit? How much of it does anyone actually eat? And is that amount a risk to health? A limit is a trading standard set from good farming practice. It is not the line between safe and harmful.

Where residues come from: on the farm, mostly insecticides. In a survey of 404 Ghanaian cocoa farmers, neonicotinoids and pyrethroids were the most used classes, about 70% of the insecticides were products approved by the cocoa board, and most farmers stored, applied and disposed of them improperly. (Boateng et al. 2023)
The store is a second source. The industry's own quality guide names pesticide use in cocoa stores, as well as on the trees, as a route by which residues reach cocoa products. (source 13)
Old chemistry persists too. Organochlorines including DDT were found in dried beans from two Nigerian towns, at levels the authors report as within international limits. (Oyekunle et al. 2017)
Where it sits: in Ghanaian cocoa a neonicotinoid insecticide was quantified in more than 10% of shelled beans and 30% of shells, and at higher levels in the shell, which is removed before chocolate is made. (Dankyi et al. 2015)
How often: in Malaysia 32% of 137 imported and domestic bean samples carried a detectable residue of one of four pesticides; in Brazil one pesticide, permethrin, was found in five of 15 samples. Detected is not the same as over a limit, and neither abstract reports an exceedance. (Zainudin et al. 2022; Machado et al. 2025)
The legal limit: European residue limits for cocoa apply to beans, fermented or dried, after the shell is removed, and where no specific level is set for a pesticide a default of 0.01 mg/kg applies. (source 14; source 15)
What a limit is: the highest residue legally tolerated when a pesticide has been applied correctly, derived from field trials under good practice. It is a test of whether the product was used properly. Jurisdictions also measure on different things: the European Union on beans without their shell, some countries on whole beans, so the same lot can pass in one and fail in another. (source 13)
Monitoring: across all foods, the European Union's 2024 programme found 1.2% to 1.8% of routine samples over a limit, and 3.6% of samples taken under increased import controls, which are aimed at consignments already suspected. (source 16)
Limit against risk: the same report assesses dietary exposure as a separate question from compliance, and concludes that the estimated risk was low for most population groups and substances. (source 16)
Testing: cocoa is a fatty matrix that is hard to analyse. One validated multi-residue method could quantify only down to 13.9 to 23.1 micrograms per kilogram, above the European default limit of 10, which shows why method choice matters when a default limit is being enforced. (Machado et al. 2025)

Not shown: The limit for any named pesticide in cocoa, in the European Union, the United States, Japan or Codex. The databases that hold them were not read, and the figures change.

Not shown: How often cocoa or chocolate specifically exceeds a limit. The European report's figures above are for all foods; its cocoa results, if broken out, were not read.

Not shown: Residues in finished chocolate, and what fermentation, roasting and shelling remove. No survey or processing study was read.

Not shown: Which products are used in stores and on ships, and what they leave. The industry publishes a manual listing the pesticides used on cocoa and those that must not be; it was not read.

Not shown: Whether organic or certified cocoa carries fewer residues. No comparison was read.

Not shown: The health of the farmers who apply these products, which the Ghanaian survey raises and this page, about what is in the food, does not cover.

Mineral oil hydrocarbons

A contaminant of packaging and handling more than of the crop. The measurements are on the packaging page.

Regulation: there is no European maximum level in law. In April 2022 member states agreed to withdraw products when the aromatic fraction reaches 0.5 mg/kg in dry foods with up to 4% fat, 1 mg/kg in foods with more fat, and 2 mg/kg in fats and oils. A 2017 recommendation had named chocolate and cocoa among the foods to monitor. (source 17; source 18)

Not shown: That the 2022 figures are limits in the legal sense. They are a statement agreed between member states about when to act.

Sources

Studies are cited by author and year and summarised, with their limits, on the research pages. The official documents are listed here. Each was downloaded and read, and the passage relied on was checked to be in it.

US Food and Drug Administration. Guidance for Industry: Lead in Candy Likely To Be Consumed Frequently by Small Children (page content current as of 2018-09-20). www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-lead-candy-likely-be-consumed-frequently-small-children
Official guidance, not law · United States
US Food and Drug Administration. Lead in Food and Foodwares (page content current as of 2025-01-06). www.fda.gov/food/environmental-contaminants-food/lead-food-and-foodwares
Official guidance, not law · United States
California Office of Environmental Health Hazard Assessment. Lead and Lead Compounds (Proposition 65 chemical page; copy archived by the Internet Archive). oehha.ca.gov/proposition-65/chemicals/lead-and-lead-compounds
Law · California, United States
California Office of Environmental Health Hazard Assessment. Proposition 65 in Plain Language (copy archived by the Internet Archive). oehha.ca.gov/proposition-65/general-info/proposition-65-plain-language
Official guidance, not law · California, United States
Superior Court of California, County of San Francisco. Consent Judgment, As You Sow v. Trader Joe's, Inc. et al., San Francisco Superior Court, Case No. CGC-15-548791 (as published by the California Attorney General) (2018-02-15). oag.ca.gov/system/files/prop65/judgments/2014-00635J3734.PDF
Law · California, United States
European Commission. Commission Regulation (EU) 2021/1317 amending Regulation (EC) No 1881/2006 as regards maximum levels of lead in certain foodstuffs (2021-08-09). eur-lex.europa.eu/eli/reg/2021/1317/oj
Law · EU
European Commission. Commission Regulation (EU) 2024/1987 amending Regulation (EU) 2023/915 as regards maximum levels of nickel in certain foodstuffs (2024-07-30). eur-lex.europa.eu/eli/reg/2024/1987/oj
Law · EU
European Food Safety Authority. Update of the risk assessment of nickel in food and drinking water. EFSA Journal 2020;18(11):6268 (abstract as held by Europe PMC) (2020). doi.org/10.2903/j.efsa.2020.6268
Risk assessment · EU
Codex Alimentarius Commission (FAO/WHO). Code of Practice for the Prevention and Reduction of Ochratoxin A Contamination in Cocoa (CXC 72-2013) (2013). www.fao.org/fao-who-codexalimentarius/sh-proxy/en/?lnk=1&url=https%253A%252F%252Fworkspace.fao.org%252Fsites%252Fcodex%252FStandards%252FCXC%2B72-2013%252FCXC_072e.pdf
Voluntary international text · International
European Commission. Commission Regulation (EU) 2023/915 of 25 April 2023 on maximum levels for certain contaminants in food and repealing Regulation (EC) No 1881/2006 (2023-04-25). eur-lex.europa.eu/eli/reg/2023/915/oj
Law · EU
European Food Safety Authority. Risk assessment of ochratoxin A in food. EFSA Journal 2020;18(5):6113 (abstract as held by Europe PMC) (2020). doi.org/10.2903/j.efsa.2020.6113
Risk assessment · EU
European Commission. Commission Regulation (EU) 2022/1370 amending Regulation (EC) No 1881/2006 as regards maximum levels of ochratoxin A in certain foodstuffs (2022-08-05). eur-lex.europa.eu/eli/reg/2022/1370/oj
Law · EU
CAOBISCO, ECA and FCC. Cocoa Beans: Chocolate and Cocoa Industry Quality Requirements (online knowledge base) (2023, as updated online). qm.cocoaquality.eu/aspects-of-cocoa-bean-quality/food-safety/pesticide-residues
The organisation's own account · International
European Commission. Commission Regulation (EU) 2018/62 of 17 January 2018 replacing Annex I to Regulation (EC) No 396/2005 (2018-01-17). eur-lex.europa.eu/eli/reg/2018/62/oj
Law · EU
European Parliament and Council. Regulation (EC) No 396/2005 of the European Parliament and of the Council on maximum residue levels of pesticides in or on food and feed of plant and animal origin (2005-02-23). eur-lex.europa.eu/eli/reg/2005/396/oj
Law · EU
European Food Safety Authority. The 2024 European Union report on pesticide residues in food. EFSA Journal 2026 (abstract as held by Europe PMC) (2026). doi.org/10.2903/j.efsa.2026.10054
Official statistics · EU
European Commission. Summary report of the Standing Committee on Plants, Animals, Food and Feed, Section Novel Food and Toxicological Safety of the Food Chain, 21 April 2022 (2022-04-21). food.ec.europa.eu/system/files/2022-07/reg-com_toxic_20220421_sum.pdf
Official guidance, not law · EU
European Commission. Commission Recommendation (EU) 2017/84 of 16 January 2017 on the monitoring of mineral oil hydrocarbons in food and in materials and articles intended to come into contact with food (2017-01-16). eur-lex.europa.eu/eli/reco/2017/84/oj
Official guidance, not law · EU

Reviewed 9 October 2026.

Not reached

These were on the list and nothing verifiable was read. Their absence here says nothing about whether they matter.

Arsenic and aluminium
Chlorate and perchlorate
3-MCPD and glycidyl esters, which concern refined fats used beside cocoa butter
Canada's maximum levels, where the list read names no chocolate or cocoa category
Limits in Latin American law
The United States Total Diet Study