Safety still not sufficiently proven

by Thomas Jensen

In the EU ethoxyquin is permitted for use as an additive in animal feed up to a maximum concentration of 150 mg/kg feed (Council Regulation (EC) No. 1831/2003).

Criticism of farmed salmon and other aquaculture products is not new. Sometimes the allegations are about antibiotics, then it can be dioxins or supposed environmental damage. At the moment it is ethoxyquin that is under discussion. Ethoxyquin is added to fish feed as an antioxidant. Its use is legal and there are no limits for ethoxyquin in fish. But recent findings from research suggest that the substance is not entirely without risks.

A 45-minute report “Toxic fish – the big health lie” that was aired by the Austrian Broadcasting Corporation (ORF) in November 2014 is still having an effect today. It haunts the internet and people like quoting it when they are letting off steam on the topic of aquaculture and, in particular, salmon farming. Among the issues the report brought up was the use of ethoxyquin (EQ) in salmon feed. Ethoxyquin is a very controversial substance and the topic was raised in the ORF report and has since then dominated some critical debates on salmon and salmon farming. Ethoxyquin is permitted in the EU as an additive in animal feed up to a maximum concentration of 150 mg/kg feed (a maximum of 100 mg/kg is permitted in dog feed). This was laid down in Council Directive 70/524/EEC, later amended by Council Regulation (EC) No. 1831/2003). In this respect, in using ethoxyquin in salmon feed Norway is not infringing any national law or international regulation but has remained strictly within the framework of what is legally permitted. And fishes in which traces of ethoxyquin were identified are not to be complained about in a purely legal sense and may be marketed because although the EU Commission has set limits for EQ in vegetables and fruit, eggs, nuts and meat it has not stipulated any limits for EQ in fish.

Ethoxyquin was first synthesized in 1920 by the German chemist Emil Knoevenagel. In the realm of chemical substances it is considered a “jack of all trades”. It prevents premature aging in rubber, retards oxidation of vitamins, and on account of its antioxidative effect can be used to prevent the skins of fruits from going brown after harvesting. Up to 2011, EQ was also permitted as a pesticide. Because the available data on its harmlessness were not sufficient, however, the EU withdrew the authorisation with Regulation (EC) No. 1107/2009. The fact that ethoxyquin may still be used as an additive in animal feed is within the responsibility of the Commission. Their agency for food safety, the European Food Safety Authority (EFSA) has been working on the necessary revaluation of ethoxyquin for years but so far without any clear results. Ethoxyquin is cheap, practical in its use and, in addition, very effective. It is reliable in preventing expensive animal and fish feed from going rancid and losing some of the sensitive vitamins and amino acids which could then lead to nutritional deficiencies during the farming process.

Although legally there is nothing to complain about, the salmon industry cannot lie back in complacency. In the recent past several findings have suggested than ethoxyquin is perhaps not quite as harmless as previously thought. Some scholars believe these results are even alarming. Victoria Bohne who was in the past involved in research at NIFES has for example discovered in animal studies that EQ can pass from the blood into the brain and is possibly carcinogenic. Moreover, ethoxyquin is said to be detectable in breast milk and in the fatty tissue of humans and can accumulate there. Tests carried out by Alina Błaszczyk also suggest that EQ can damage the genotype. During research on human blood cells she found that the substance leads to increased chromosome breakage. The Dutch toxicologist Henk Tennekes suspects that EQ could influence brain development of foetuses during pregnancy. Although these are only signs and not generally recognized scientific evidence, they still give rise for concern.

No danger through ethoxyquin in current salmon consumption

If use of ethoxyquin in feeds is to be continued then even the tiniest doubts about its safety will have to be dispelled completely. And particularly because in the meantime tests have confirmed that the substance can be absorbed in minute quantities from the feed into the fish flesh itself. And this is an urgent matter, because up to now no official tests have been carried out on ethoxyquin, neither with regard to long-term consequences nor possible carcinogenic risks or neurotoxic effects. EFSA, the responsible European authority for food safety, has merely stated in connection with the suitability of ethoxyquin as a feed additive that the available data material is insufficient for an assessment of its safety for consumers. That is grist to the mill of aquaculture critics who anyway accuse the EU authorities of being too close to industry when pollutants in farmed fish are at stake. After all, in 2013 the EU Commission raised the limit for endosulfan in farmed salmon from 0.005 to 0.05 milligrams per kilogram, i.e. tenfold. Like ethoxyquin, endosulfan is suspected of impairing fertility in men, of being a neurotoxin, and possibly causing cancer.


As early as 2010 various fish species (salmon, halibut, cod, trout) and fish feed were examined at NIFES to determine their ethoxyquin content. The highest concentrations were found in salmon, which contained on average 0.17 milligrams EQ per kilogram of fillet. During the years 2005 to 2009 the mean values were still between 0.02 and 0.04 mg/kg. The Chemical and Veterinary Investigation Authority in Freiburg, Germany also detects ethoxyquin more or less regularly in salmon flesh during routine controls. This is not pleasant but still gives no cause for exaggerated concern when one looks at the Maximum Residue Limits (MRL) of other foods and the average consumption volume of fish in Germany. A person weighing 70 kg would have to eat 1.75 kg salmon per day (based on an ethoxyquin content of 0.2 mg per kg salmon fillet) in order to reach the Acceptable Daily Intake (ADI) of 0.005 milligrams EQ per kilogram of body weight – the intake level that is considered safe by the World Health Organisation. In other words, even a generous 300 gram portion of salmon would only use up 17% of the acceptable daily intake of a person weighing 70 kg.

The Norwegian Food Safety Authority (Mattilsynet) does not fear any endangerment to human health from eating salmon provided one adheres to the limits.

The Norwegian Food Safety Authority (Mattilsynet)
thus fears no adverse effects on human health through consumption of salmon provided one adheres to the set limits. Although the EU has not set a limit (MRL) for salmon and other fishes Norway in the meantime carries out routine controls to check EQ levels. The highest values measured during these controls were so far about 0.2 mg EQ/kg salmon. Even in Japan, where ethoxyquin limits are particularly strict (the MRL for fish is 1 mg/kg and for crustaceans 0.2 mg/kg) there have been no complaints about any deliveries of Norwegian salmon because of too high EQ values. Compared to other foods for which an MRL has been set salmon often even gets better results. The EU limit for ethoxyquin in pears, for example, is 3 milligrams per kilogram. That is three times as much as the permitted MRL for fish in Japan and the content in salmon comes nowhere near that.

Any suspicion of possible risks must be eliminated

Some countries such as Japan have set limits for ethoxyquin in fish but the EU has not. On the one hand, the FAO has put ethoxyquin on the list of chemical additives for fish feed that are considered safe. On the other hand, in the CODEX FAO/WHO an ADI of 0.005 mg per kilogram body weight has been set. The Acute Reference Dose (ARfD) is 0.5 mg/kg body weight and that is even one hundred times higher. (The ARfD is the estimated quantity of a substance in a food that based on current knowledge can be ingested over a short period of time – normally on one day – without appreciable health risk to the consumer, taking into account sensitive population groups including children and the unborn). The different approaches taken throughout the world reveal just how uncertain the responsible authorities are with regard to risk assessment of ethoxyquin. Whilst some perhaps tend towards exaggerated caution, others are possibly too optimistic or even reckless.

There are no limits for ethoxyquin in fish. However, the WHO recommends that an acceptable daily intake (ADI) of 0.005 milligrams EQ per kg body weight is not exceeded.

Under such conditions it is not easy to reassure consumers and dispel their fears and concerns. As long as there are no satisfactory answers to important questions the gaping hole will be filled with conjecture, speculation and suspicion.  Is ethoxyquin harmless or dangerous? Can it accumulate in the body to perhaps years later trigger cancer? How great is the risk that the substance will interact with other absorbed pollutants in the body? What does it mean that ethoxyquin can apparently cross the blood-brain barrier? Can long-term consequences be ruled out? All of this has to be investigated impartially and scientifically. And this should be done as quickly and thoroughly as possible to dispel any remaining doubts among consumers, to give fish farmers the necessary certitude when handling feeds, and of course also to avoid damaging trust in product safety and thereby preserve the positive image of salmon. When the EU Commission laid down Maximum Pesticide Residue Levels for food and feed products in February 2006 fish was excluded… as an exception as it was called at the time, but up to this day nothing further has happened in Brussels. Although the EFSA is currently examining all feed additives this process is taking agonizingly long.

And time is pressing, for if doubts – however small – about ethoxyquin cannot be dispelled the substance will have to be taken off the market and replaced by “less dangerous” antioxidants. And one can only begin to imagine how hard that would be, for the range of possible applications is extremely varied. The International Maritime Organization (IMO), for example, demands that prior to shipment antioxidants like ethoxyquin be added to fish meal to prevent spontaneous combustion during transport and storage. The FDA in the USA permits the use of ethoxyquin not only for preserving animal feed, dried grain and millet, but it can also be added to chili and paprika. The debate about ethoxyquin therefore concerns not only salmon and other seafood products but many more foods and a wide range of applications. Reason enough why we finally need to know more about this substance and the potential risks it entails.


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