I do not condone the industrial exploitation of blue-fin tuna, the population of which is threatened. Importantly, tuna with a gaudy, crimson-tinged colour is being offered for sale. This may be marked as yellow-fin tuna (imported) but this is not always the case. The ‘suspect’ coloration carries on to the cooked product. I have never in my life seen cooked tuna with such a gaudy pink/crimson colour. The taste? Let us say there was no suggestion that it was off, but if one wanted a whiff of the sea, it was definitely not there. As a medical person, the colour of the raw tuna reminded me of the cherry-red discoloration of a person who died of carbon monoxide (CO) poisoning. Sure enough, although I was unaware of the fact then, thanks to Google, the gas is actually used on tuna (and Mahi Mahi) to preserve a ‘fresh’ pink appearance of the product, called CO-treated tuna
CO-treatment fixes the (gaudy) pink colour which will last for weeks, making it impossible to evaluate the freshness by sight alone. CO-treated tuna has only one aim and that is to entice customers to purchase it irrespective of the lack of freshness or quality. More importantly, CO-treated tuna is banned (treatment and importation) in the EU. The main reason why Canada, Japan, and Singapore, also ban the CO-treatment and importation of treated fish is not because of the chemical, but because of ‘fraud’. (https://thefishsite.com/articles/how-to-optimise-colour-in-tuna). CO-treated tuna has been linked with health risks because there is no record of its prolonged handling. (https://www.hawaiianfreshseafood.com/single-post/2016/08/11/Carbon-Monoxide-Treated-Fish-What-you-need-to-know).
Mediterranean blue-fin tuna fetches top dollar ($1000 per kilo) in Japan. Surely none of that is coming on Maltese plates unless sourced from part-time fishermen during the tuna season.
The authorities should look into this when they wake up. I do not know how widely this product has permeated the local market; it is up to the authorities to determine that. A squeak from the local fish supply industry is expected. There is absolutely no other plausible explanation for crimson coloured tuna but CO-treatment.
Dr Albert Bezzina
Mosta