It is no surprise that it is extremely important to use very fresh fish for sushi or sashimi or any other raw fish consumption. If the fish is not very fresh when eating it, our health can be at risk. The freshest moment would be when the fish is in its pre-rigor mortis state. But what exactly is pre-rigor mortis?
Like with human bodies, fish also goes through several stages after death of which the first stage is pre-rigor mortis followed by rigor mortis. When a fish gets into the rigor mortis stage they start to show signs of death, generally characterised by progressive muscle stiffening as a consequence of coagulation of muscle protein due to a lack of oxygen. The rigor mortis stage starts approximately three hours after death with an undesirable change in the quality and structure of the fish as result. This means that for raw consumption, the fish should be processed and frozen within the first three hours after the catch or death, also called the pre-rigor mortis stage.
Our tuna is also pre-rigor mortis: processed and super frozen on board at -60°C within 1-2 hours after catch. We specifically choose for the extremely low temperature of -60°C instead of -20°C since tuna loses a lot on quality (colour, structure, smell and taste) when you store it at -20°C. When directly stored at -60°C during the pre-rigor mortis stage there will be no changes in quality of the tuna anymore. This means that when you defrost it, the quality is the same as if the tuna was caught 1-2 hours ago!
With this technique we have been able to offer a very stable und high quality tuna that is still soft, limp and of excellent quality but most importantly also safe for raw consumption.
In Europe we encounter a lot of treated tuna with several E-numbers added. Now you may ask why this is done when it is not necessary? The answer is simple: to make the tuna look better than it is. Treated tuna is never pre-rigor mortis, so the quality is already way inferior from the start. In addition, treated tuna is not 100% natural and has a higher risk of food poisoning.