Aquaculture for all

Wholesalers Advised to Look Out for Treated Tuna

Tuna Sustainability Economics +7 more

UK - Seafish's regulation team has recently been made aware of an issue with some tuna that is being placed on the UK market.

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A practice has emerged that involves fermented vegetable extract being injected into low grade tuna in order to restore its red colour. It is then being mis-sold as high-grade tuna at premium prices.

The UK has always held that this product and process is not permitted for tuna. However, some EU member states interpreted the regulation differently and were permitting the use of vegetable extract as flavouring.

Seafish has worked with tuna importers from four member states, including the UK, to alert the EU Commission to the issue. It has now confirmed the UK position is correct and issued official guidance to other member states. However, until the process is stopped there could potentially be treated tuna on the UK market.

It is believed that this practice is predominantly happening with tuna that is being processed in Spain, France and Italy. It is thought that the main buyer of this product will be wholesalers.

It is very difficult to identify the difference between the treated and non-treated tuna. The flavour will not be noticeably different. In terms of the look of the treated tuna, it might be overly red/pink in colour to the trained eye.

Seafish is therefore advising wholesalers to check their supply chains thoroughly and speak to their suppliers to ensure that they are not treating their tuna.

The following signs will help you identify treated tuna:

  • Bright red in colour and significant liquid in the pack which is not the colour of tuna blood.
  • Vacuum packed tuna.
  • Softness of flesh with crumbling fibres on the surface, remaining even after cooking.
  • The label might declare the use of antioxidants such as, E-331(Sodium citrates), E300 (Ascorbic acid), E 301 (Sodium ascorbate) as well as an acidity regulator E500 (Sodium carbonates) and salt. These additives are needed to maintain the correct conditions for the reaction but they are not always declared.
  • The label might declare the use of vegetable 'aroma'.
  • After exposure to the air the tuna will blacken. This can take several hours as the antioxidants are added to slow this reaction.

If you suspect that you are being sold low-grade tuna as high-grade, please alert the FSA (

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