Tuna and Sea Urchin (Uni) products are sensitive species and are Superfrozen at peak freshness here at Riviera Seafood Club, to ensure you have the highest quality product. To maximize this quality, we suggest defrosting and using superfrozen products as soon as possible to avoid any risk of color change/oxidation while storing in a conventional home freezer.

If your superfrozen products are not going to be consumed immediately, they can be stored in your conventional freezer for approximately 1 week after receiving, for high quality sashimi preparations and up to 2 weeks before seeing changes to quality. Check your individual product for a final use (cook) by date. 

Defrosting Instructions:

Thawing in an ice bath is the best method to defrost your products to ensure a quality experience and best end result. Follow the instructions below:

1. Fill a large bowl with water and ice (about a 40/60 ice to water ratio). Maintaining the chain of cold is arguably the most important part of seafood handling and ensuring the best end result for your meal.

2. Fully submerge the products in their packaging and allow them to thaw from 30 minutes to 1 hour depending on the thickness of the portion(s). When done thawing, your seafood should be firm to the touch but pliable. 

3. Remove them from their packaging and pat dry. Cut and enjoy within 24 hours when storing in the refrigerator. 

Fresh (Not Frozen) Seafood Storage and Handling Instructions

The Bluefin Tuna (Senaka) cut is the only product we carry that arrives fresh (not frozen). This product should be stored in the coldest part of your refrigerator upon arrival. Use within 1-2 days of receiving for best results. 

You can see a video on how to prepare this cut here. 

What is Superfrozen Technology and How Does it Work?

Conventional Freezing

We all know that if you put a bottle of water into a freezer the ice EXPANDS, eventually breaking the bottle. On a cellular level, when fish freezes, the ice crystals break through the membrane of the cell, and later when the fish is thawed there’s an accompanying pool of water, and a “spongy” texture to the thawed fish.

Superfrozen Technology

Superfreezing is a practice widely adopted in Japan, where foods are “flash frozen” at -60-70°C (superfrozen) temperatures. Maximum ice expansion occurs at -5°C, but CONTRACTS at lower temperatures, so during superfreezing, water molecules pass through the -5°C phase so quickly that they don’t have time to expand and contract, thus never lysing the cell membrane.The result is a firm, springy texture to the meat, with minimal loss of freshness and nutrients.

The most dramatic example of this technology is that after being frozen immediately after harvest and stored at superfrozen temperature for 2 YEARS some pieces of tuna in fact can “curl up” upon thaw--as they didn’t have time to go into rigor at time of capture or harvest! In Japan, it is common to see small superfreezers in families’ homes to extend the shelf life of food significantly, without losing quality.