Is pangasius safe to eat?

By Simon Bush and Tinka Murk

Pangasius has emerged as one of the most controversial seafood products in both Europe and the US. In a recent paper published in Reviews in Aquaculture we ask whether the controversy justified. 

Full of poison?

Pangasius has emerged as a key aquaculture species in Vietnam which accounts for more than 90% of what is sold on the international market. The industry has become an important source of employment and wealth generation in the Mekong Delta. In short it is one of the key success stories of Asian aquaculture.

The industry has expanded in terms of both production and trade. Pangasius is now traded to well over 100 countries worldwide. It is also one of the top five most consumed species in both the US and the EU, and is rapidly expanding in Asia and other regions of the world as a cheap source of fish protein.

But at the same time, there have been a number of claims made about the safety and sustainability of pangasius. These have ranged from statements that pangasius is ‘full of poison’ stemming from the ‘heavily polluted Mekong River’. The group making these claims is very broad. It includes membes of the European fishing industry and US farmed catfish industry concerned about protecting their market Europe. But it also extends to environmental NGOs and politicians.

Their claims have been successful to the extent that they continue to be circulated via social media. But on the other hand have not affected exports to any great extent.

It’s a complex story which made it interesting for us to bring together sociology and toxicology to examine how mass mediated claims are confusing how the public understands the difference between hazard and risk in aquaculture production.

Testing claims

In our paper published in Reviews in Aquaculture we compare these various claims over the presence of toxic compounds in pangasius we decided to study exactly what risk they actually pose.

In doing so we first systematically documented claims across television, radio, newspaper, online and social media made in the US and different European countries from 2008 to 2014. When available we collected the levels of the compounds named as well as the sources cited. We also took all notifications of restricted substances found in imported pangasius to the EU recorded in the EU Rapid Alert System for Food and Feed, or RASSF.

The RASFF database actually presents the worst case situation, given the products listed were not allowed into Europe. We then calculated the amount of pangasius fillet that could have been safely eaten every day. The highest level for every restricted substance in the RASFF database was used to calculate the maximum daily safe consumption.

Finally the results were compared with the various accusations made in the wider media.

The most surprising result was that none of the suggested toxicological risks were supported with actual data on chemical analysis or intake levels. The compounds that were suggested to pose a risk were also not the ones that were reported in the RASFF database.

Even if we take the highest levels of the toxic contaminants ever reported in RASFF alerts for Vietnamese pangasius, daily consumption of that filet would still be safe based on the toxicological risk assessment.

The maximum amount of filet that could have been consumed without any adverse effects would be between 3.5 and 167 kg per day for the entire life of a 70kg adult when considering pesticides and between 0.6 and 303 kg filet/day for the filets recalled in the last 10 years because of the presence of preservatives and antibiotics.

It is important to state that in the vast majority of imported Panga no toxic compounds can be found at all. Based on our study we conclude that consumption of pangasius available on the European market does not pose any concern for the health of the consumer.

Mass mediated risk

From a sociological perspective what we see is that claims made come from a poor understanding of the difference between potential and real health risks.

For sociologists this opens up questions like who is responsible for defining risks? How do different societal groups create uncertainty that influences decisions over production and trade? And what economic and political interests lie behind the claims that are made?

The confusion that this misrepresentation leads to refers to this ‘mass-mediated risk’. This  can be characterized as an ever wider group of non-experts giving voice to the definition and interpretation of risk with little engagement with or reference to the scientific process of risk assessment.

The pangasius case also shows how mass-mediated communication can shift attention from claims based on science to claims based on political and economic interests. This means that any reference to a chemical gives the impression of danger without understanding the risk they might pose to human or environmental health.

Given that mass mediated claims hold considerable consequences for the sustainable and safe expansion of aquaculture, building an understanding of how policy makers, companies and consumers respond to such claims is an important next step of the research.

Hazards are not risks

This is not the first example of confusion between risk and hazard. And for the aquaculture industry it certainly won’t be the last. People especially worry about synthetic compounds that could be present in their food such as pesticides and plasticizers.

Scary information is published about the potential risk of these compounds, but hardly ever about the actual levels nor the amount the body can handle before the safe limit is reached.

In the future its necessary to increase the understanding of risk assessment of our environment and  food. It is also necessary to the make scientific interpretations of risk publically available. This is important for ensuring that the great uncertainty being generated in the media about aquaculture can be countered by improved public knowledge.

But the very first step is to make clearer to the public and policy makers alike that the hazard of a compound does not necessarily pose a risk. A potential risk only is a risk if you actually are exposed to it in higher levels than even the most sensitive person, including unborn children, can handle.

Want to read more?

Murk, A. J., Rietjens, I. M., & Bush, S. R. (Forthcoming). Perceived versus real toxicological safety of pangasius catfish: a review modifying market perspectives. Reviews in Aquaculture. xx:xx-xx

Wright, J. (2015) Risk v. hazard: A dispassionate look at pangasius. Global Aquaculture Advocate, November 30, 2015 [online]

Little, D. C., Bush, S. R., Belton, B., Phuong, N. T., Young, J. A., & Murray, F. J. (2012). Whitefish wars: Pangasius, politics and consumer confusion in Europe. Marine Policy36(3), 738-745.


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