Q: What is sashimi-grade tuna?

A: Sashimi grade and sushi grade are interchangeable terms. Basically, the term identifies the fish as safe to be eaten raw. However, by FDA standards, all sushi-grade or sashimi-grade seafood must be frozen to -4° F (for 7 days) or -35° F (for 15 hours) prior to consumption. In the case of Tristan, we freeze our tuna at -76° F, so the product is safe to eat after 8 hours at this temperature.


Q: Is there a difference between “super-frozen” and “ULT frozen” seafood?

A: No. They both mean the same thing: freezing a food product to -76° F or -60° C.


Q: Can a ULT frozen tuna be stored in a regular freezer at 0° F?

A: Yes. However, once the ULT tuna is subjected to warmer temperatures, it begins its natural process of deterioration. Although the product is still frozen, once thawed, it will only hold the natural characteristics of tuna for a very short period of time. You might see the product start to turn brown or an “off” color. If you only have access to a regular freezer, our recommendation is to place the ULT tuna in the deepest part and use within five days of arrival.


Q: Once you re-fresh the ULT tuna, can you refreeze?

A: No. Once defrosted, the product has to be used.


Q: How do you properly re-fresh a Tristan ULT tuna portion?

A: It’s fairly simple. Please refer to the step-by-step instructions located in the product section of this website. In addition, we offer Tristan ULT Fresh™, a complete #1 grade loin that we expertly re-fresh for customers using our proprietary process. We handle the work for you and ship overnight-directly to your door.


Q: What is the difference between the grades of tuna?

A: Like any premium product, tuna prices are based on grades. A tuna can earn one of four grades: #1, #2+, #2 and #3. Each tuna is graded based on five indicators:

  • Initial appearance
  • Size and shape
  • Color
  • Texture
  • Fat content

#1 Tuna – Should be at least 60 lbs. or bigger, generally a larger loin and more fat. It should have a fine, smooth texture and the core sample should reveal fat content. As a general rule, the more fat, the better the fish. There should be no discoloration of the flesh: it should be bright and shiny. The bloodline should be a darker red than the meat and have no brown or black coloration. Tristan standards also call for #1 tuna to be “live caught” fish.

#2+ Tuna: The nape and belly might be slightly fatter when compared to a #1 tuna. The flesh color might still be a nice red, but slightly discolored closer to the skin. This grade has less fat when compared to a #1 tuna. Color is the most important factor between determining between a #1 and a #2+ tuna.

#2 Tuna: This is the tuna of choice for those who don’t want to pay for a #1 grade tuna and for dishes that will be cooked. Although not sushi-grade, some lower-end restaurants use this grade for sushi.

#3 Tuna: Only used for cooking. Most likely the color has already turned brown or greenish. The preferred cooking method for #3 tuna is the grill.


Q: What is CO-Treated Tuna?

A: First, let’s set the record straight. CO (carbon monoxide) is a poisonous gas. CO food treatments are banned in many European countries, Canada and in many Pacific Rim countries. Lesser-quality tuna processors will treat their tuna with CO to maintain the recognizable red color of the tuna for longer periods of time. Typically, a fresh tuna loin will start to change color naturally after 3 to 4 days. With a CO treated tuna product, the red color will remain for almost 3 weeks. In addition, CO is often used to hide the actual grade of the tuna. A CO-treated #3 tuna will sometimes look like it is sushi grade. Customers have no idea how long the tuna has been out of the water or the actual grade of the product. That is why there is a very large price difference. CO- treated tuna is often sold as low as $6/lb. A natural, properly handled fresh tuna loin will wholesale for $11+/lb. Tristan never treats its products with CO.