June 29, 2009
Ultrasound Makes Catfish Taste Better
By Dave Hurteau
One solution to the world’s water pollution problems could be something you can’t taste, touch, see, smell, or hear. Especially hear. Ultrasound, the range of frequencies beyond the limits of human hearing, is starting to emerge as an effective water treatment that is more sustainable than chemical dosing. Researchers are discovering that ultrasound performs well on algae, and that’s only the beginning. Ultrasound can remove a variety of pollutants in water, including those that affect the taste of America’s favorite fish, the catfish.
The USDA has been focusing on reducing off-flavor in catfish, caused by their unique tendency to absorb and express pollutants in their environment. It’s part of a broader program to improve marketability, which also includes reducing mortality rates in farmed catfish. Conventional treatment of tanks and ponds consists of substances like diuron, sodium chloride, hydrogen peroxide, titanium dioxide, and copper, but aside from their expense any one of these can lead to a cycle of greater dependency. So far, the results of ultrasound promise a more sustainable approach. Researchers at the UDSA’s Stoneville, Mississippi unit found that an ultrasound regimen decreased bacterial biomass by 60% in tanks, without impacting fish growth. In production ponds, ultrasound also demonstrated an ability to change the density of algae.