Ethylene oxide: The main character in a very long food safety scandal

In September 2020, news surfaced about food products being recalled from the supermarkets due to them being contaminated with ethylene oxide (ETO).

Are these recalls a sign of a functioning food product controls?

What is ethylene oxide?

To the chemist, ethylene oxide (aka oxirane, aka epoxyethane, aka oxacyclopropane) is one of the most useful reagents there is.

It is a strong alkylating agent and is used in a wide variety of reactions.[REF01]

In addition to its use in synthetic chemistry, it is also widely used as a disinfectant, for instance for surgical equipment.

In some countries, ethylene oxide is also used as a pesticide.

In the European Union, its use as a pesticide is banned.

The reason is that it is a strong alkylating agent.

The alkylating agent: the reason why ETO is banned as a pesticide in the EU.

Genetic material as we know it consists of paired-up chains of amino acids.

In their natural state, these chains adopt the spatial arrangement of a double helix.

This requires the individual amino acids to be of a specific shape, which is to say a specific molecular structure.

These two chains (also referred to as strands) fit each other like lock and key.

An alkylating agent is a molecule A which reacts with another molecule B in such a way that it adds an alkyl chain to molecule B.

If an alkylating agent encounters one of the amino acids of our genetic material it will add an alkyl chain to that amino acid, thus changing the molecular structure of that amino acid, which in turn makes it impossible for the two strands to form the double helix structure.

As a result, the genetic information is lost and mutations occur.

The aspect that makes ETO so useful to chemists is the reason why it is harmful to life.

This is why ETO is banned as a pesticide in the EU.

What’s the scandal?

In early September 2020, the Belgian Federal Agency for the Safety of the Food Chain (FASFC) has alerted the EU’s Rapid Alert System for Food and Feed (RASFF) to findings that sesame seeds imported from India were contaminated with ethylene oxide (ETO).[REF02][REF03]

The contamination exceeded the threshold value by up to three orders of magnitude.

This leads to numerous product recalls in many European countries.

The recalls affected traditional products as well as products which carried Green EU-label.

However, different member states recalled different products to different extents, which means that consumers are not protected equally throughout the EU. By way of an example, the list of products which were recalled in Belgium can be found here.[REF04]

For the EU, the safe level of ETO in food is set at 0.02 mg/kg.[REF05]

This reflects the fact that prolonged and regular exposure to low levels of carcinogens are more likely to result in cancer (or comparable health problems) than short term exposure to higher levels.

Experts agree that there is in fact no safe level for compounds such as ETO.

Sesame seeds are not only found on the top of bagels they are also processed and find their way into other food in the form of so-called agents, ingredients which impart certain textural qualities on the food product in question.

For instance, locust-bean gum (E410)[REF06] is used in ice-cream as a thickening agent.

Incidentally, locust-bean gum has also been implicated in the ETO scandal.

The issue here was that some member states considered relaxing the product recalls for products containing locust-bean gum, which was known to have been treated with ETO, but whose contamination was below the limit of detection (and thus below the legal maximum residue levels).

If a contaminant is present in a vast array of products (even in minute quantities), consumers are subjected to this contaminant on a regular basis.

For instance, locust-bean gum is used in inter alia ice cream, breakfast cereals, meat products, confectionery, fermented milk products and cheese.

This is why the maximum residue levels (MRLs) of contamination are so low.

Is the system working?

The fact that many hundreds of products have been recalled after initial reports on ETO levels in sesame seeds and locust-bean gum became known shows that the European system of food controls is working.

The fact that some member states were lobbying for the rules to be relaxed shows that any tool is just as useful as the person using it.

While France has recalled over 6000 products, in Germany the number was dramatically lower; only 54 — an extraordinary difference.[REF07]

Does this mean France cares more about their citizens?

Does this means Germans have a higher tolerance towards ETO?

Of course, none of the above.

First of all, it reflects the fact that product recalls fall under national jurisdiction.

It also reflects the fact that while an alarm may have been raised about any kind of imported food or food additive, this does not mean that this food or additive appears uniformly on the European market.

What remains important is the work of independent watchdogs like Foodwatch.[REF08]

Food safety and sustainability… What’s the link?

Three of the United Nations Sustainable Development Goals are primarily related to health:

  • SDG 3 focuses on health
  • SDG 2 ‘Zero Hunger’ includes the eradication of hunger and nutrition-related disease, and
  • SDG 6 ‘Clean Water and Sanitation’ is a prerequisite for health.

A crucial milestone of the Agenda for Sustainable Development Goals is universal access to safe food.

Despite this, an estimated 600 million people get sick from consuming contaminated food each year, with 420 000 of them dying. [Ref 09]

Food safety is also important for economic development and international trade.

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Dr. Audrey-Flore Ngomsik

Dr. Audrey-Flore Ngomsik


Co-Fonder of Trianon Scientific Communication. Expert in Corporate Social Responsibility & Sustainable Development for profitability—