It is no surprise that the inside story on frozen seafood would include a Port Lavaca connection. A 1940 Port Lavaca Wave article credited Charles Everett Fisher as the first businessman to put Port Lavaca on the seafood map. Started in 1915, Fisher Fisheries originally only sold fish and oysters but later became the first shrimp dealer. In 1921, C.E. Fisher shipped the first carload of shrimp in the world from Port Lavaca. The experiment sent 20,000 pounds of shrimp to San Francisco, which was re-iced at every icing station. At the time, the shrimp was sold at $15 per hundred pounds. As many as 2,500 pounds of trout at a time was also successfully shipped by Fisher. By 1928, Port Lavaca was the largest shipper of seafood in the United States.
Since seafood is a perishable item, the biggest factor in keeping it fresh is time. So which is best to eat: fresh or frozen? It all depends on food preferences and location, location, location. Fresh Alaskan salmon could take 10 to 24 hours to reach its destination. It must be properly cleaned, packaged and refrigerated during transport. Frozen products are easier to transport and can be the better option for anyone not living in the area a particular species is caught or a landlocked state like Kansas. Storage temperature is the key to keeping all seafood products at their best. For example, a white fish like cod or flounder that is quickly frozen shortly after it is caught will remain in prime condition for up to 8 months if store at minus 20 degrees. The same fish stored at 15 degrees (still frozen but 35 degrees warmer) will only maintain its top condition for one month.
Over the years, many improvements have been made, especially with mechanical freezer and refrigeration units. Shrimp moved from being shipped on ice to being frozen in 5 pound blocks to a process known as IQF (individually quick frozen) that allows the customer to thaw small amounts at a time as opposed to an entire block. Clarence Birdseye discovered that quick freezing reduces the size of ice crystals that form inside the food by reducing the time food spends in the 31 to 25 degree range where the crystals form. Conventional freezing might take ten hours for a package of fish with six hours in the 31-25 degree range but only 90 minutes using IQF technology which shortens the critical ice crystal time zone to only 25 minutes.
At his plants in Dickinson and Port Lavaca, Clifford Hillman was the first to use cryogenic technologies in oyster processing in the late 1980’s. In his process, oysters are washed, shucked and placed onto trays. Next, they go through a rinsing station where workers wash away any remaining bits of mud or shell. From there, the cleaned oysters are “quick frozen” to minus 109 degrees using liquid nitrogen as they pass through a 12-foot tunnel. As the trays of oysters exit the tunnel, they are sprayed with water that forms an ice glaze. These frozen oysters are packed into insulated boxes, stored in freezers, and then distributed across the United States.
Who would ever think oysters could be frozen whole, shucked or on the half-shell? Think again. The process of IQF oysters not only solves concerns with shelf-life for stores and restaurants but the labor involved in shucking the oyster is already done. More importantly, a post-harvest treatment like quick freezing reduces the potentially deadly bacteria Vibrio vulnificus to non-detectable levels making them safe for raw consumption.
*Rhonda Cummins is the Calhoun County Extension Agent for Coastal and Marine Resources with the Texas A&M Agrilife Extension Service and the Texas Sea Grant College Program.