Industry Insights · 17min read

Contaminants & Toxins in Foods

Learn which substances to review and request laboratory tests for in foods. 

Because foods labelled as organic may not contain hormones, artificial additives, chemicals, antibiotics, or GMOs, you are already on the right track to avoiding unwanted contaminants if you order organic certified ingredients. However, the global food supply chain is highly complex, and contamination can happen at several different points. 

The European Food Safety Authority (EFSA) classifies contaminants into the following categories: natural toxins (e.g. fungi, algae), environmental contaminants (e.g. pollutants present in air and water), process contaminants (e.g. substances that form when food is subjected to higher temperatures), metals (e.g. lead) and inorganic substances (e.g. fluorine). 

On an international scale, organisations like the Food and Agriculture Organisation of the United Nations (FAO) and the World Health Organization (WHO) hire independent scientific experts to continually review scientific data and studies to develop international standards that limit exposure to toxins and contaminants in foods. In the EU, the European Commission relies on independent reviews and conclusions by EFSA to draw up regulations for pesticides in plant products, contaminants in feed, chemicals in foods and more.  

Below we examine some of the most prevalent contaminants in dry, plant-based foods and ingredients.


Ethylene Oxide

In September 2020, Belgium reported ethylene oxide's presence in sesame seeds of Indian origin to RASFF. This raised the alarm across member states because the EU imports over 50% of its sesame seeds from India. Because sesame seeds are a common ingredient in dry foods with long shelf lives, as of February 2021, 500 further reports of contamination had been issued across the EU, resulting in thousands of product recalls to date.

Type of contaminant Chemical disinfectant
Affected foods Sesame seeds
Effects on health Genotoxic carcinogen
Maximum residue limit in the EU 0.05 mg/kg



Mycotoxins are a naturally occurring type of toxins when certain fungi grow on crops and harvested foods. And now climate change is giving rise to new challenges. Although hundreds of mycotoxins exist and are screened for regularly, aflatoxins and ochratoxin A in particular, are considered some of the most prevalent in dry foods and ingredients. 



Aflatoxins are a type of mould that occur before harvest in hot and humid environments or during storage when exposed to poor conditions. Aflatoxins not only pose a risk to those consuming foods but also those handling them.

Type of contaminant Mycotoxin (the strains Aspergillus flavus and Aspergillus parasiticus)
Affected foods Peanuts, tree nuts, corn, rice, spices, vegetable oils, cocoa beans
Effects on health Genotoxic, hepatotoxic & carcinogenic
Maximum residue limit in the EU Differs per food category (refer to Annex, Section 2.1)

Read more about aflatoxins here on our blog.


Ochratoxin A (OTA)

OTA is one of the most toxic and common natural contaminants in foods. Numerous studies have found that it specifically targets the kidneys and liver.

Type of contaminant Mycotoxin (the strains Aspergillus ochraceus, A. carbonarius, A. niger, Penicillium verrucosum)
Affected foods A wide range of commodities, including cereals, pulses, coffee, dry fruits, cacao, nuts and spices
Effects on health Genotoxic & carcinogenic
Maximum residue limit in the EU Differs per food category (refer to Annex, Section 2.2)



Coumarin is a natural and fragrant compound that occurs in high levels of cassia cinnamon. It is also present in trace amounts in Ceylon cinnamon as well as a handful of other plants. Today, many manufacturers opt to utilise cassia cinnamon as a spice over Ceylon cinnamon because of its more distinct flavour and lower price point. In 2004, the EFSA established that it is safe to consume up to 0.1 mg of coumarin/day.

Type of contaminant Natural plant compound
Affected foods Cassia cinnamon, ceylon cinnamon, tonka beans, sweet clover
Effects on health Liver damage & impaired cognitive development
Maximum residue limit in the EU n/a




Cadmium is present in the environment naturally but can also enter the environment industrially through industrial or agricultural processes. Today, the most common type of cadmium exposure is via foodstuffs which have taken it up from the soil. According to FAO/WHO, it is safe for humans to consume 25 μg/kg body weight per month. The cocoa industry, in particular, has undergone strict scrutiny in recent years for the high levels of cadmium that have become prevalent in some cocoa plantations. Hence, cocoa products are only permitted onto the EU market if they can prove that their Cadmium content does not exceed certain levels.

Type of contaminant Environmental contaminant (heavy metal)
Affected foods Cereals, cocoa, vegetables, nuts, pulses, starchy roots/potatoes, meats
Effects on health Carcinogenic & nephrotoxic
Maximum residue limit in the EU Products with <30% cocoa content (0.1 mg/kg), products with 30% - 50% cocoa content (0.3 mg/kg), products with >50% cocoa content (0.8 mg/kg), cocoa powder (0.6 mg/kg) 



Environmental contamination of lead primarily occurs through mining, smelting, manufacturing and recycling practices. According to WHO, any level of ingestion of lead, however small, is likely to have negative effects on human health. Children are particularly vulnerable to lead poisoning because lead has permanent adverse effects on developing brains. 

Type of contaminant Organic and inorganic environmental contaminant (heavy metal)
Affected foods Meat, fish, cereals, grains, vegetables, water
Effects on health


Maximum residue limit in the EU Differs per food category (Section 3.1)



Arsenic is a natural element that is present in water, air and soil and thus occurs in almost every crop. It is important to differentiate between organic and inorganic arsenic because, while organic arsenic contains carbon and relatively for consumption, inorganic arsenic is extremely toxic. 

Type of contaminant Natural element
Affected foods Grains, rice, water, coffee, fish, dairy, vegetables and algae
Effects on health Carcinogenic & causing skin lesions
Maximum residue limit in the EU Differs per food category (Annex


Imagery: (1) Girl with Red Hat, (2) Tetiana Shyshkina, (3) Diana Polekhina and (4) Tuan Nguy N Minh via | Video: Mycotoxins and Climate Change - How Europe Contributes to Global Efforts by EFSA via YouTube


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