Of all the food we eat, fish is considered one of the most nutritious. Yet, it is delicate. It does not last long or travel far from the water source before it spoils. Can you imagine what a couple of more days of shelf life would do for the fish industry? That is exactly what ozone can do for fish.
Increasing shelf life of fish
In a study done by the World Academy of Science, “Extension of Fish Shelf Life by Ozone Treatment,” scientists treated trout for two hours and were able to increase the shelf life from four to six days. The fish were kept at 41º F (or 5º C). In this process, while bacteria and viruses grew slower, the taste of the fish was not impaired. If you’ve been following ozone related topics, by now you probably already can guess that ozone is able to do this because it kills bacterial spores and viruses that cause decay and then reverts back to oxygen. What are the benefits of using ozone for fish? While more studies need to be done on the benefits of ozone for fish, the U.S. Food and Drug Administration (FDA) clearly states in a report on methods to reduce/eliminate pathogens from produce that “…bacterial pathogens such as Salmonella Typhimurium, Y. enterocolitica, S. aureus, and L. monocytogenes are sensitive to treatment with 20 ppm ozone in water…” Also, fish storage is improved upon by use of ozone. The FDA says: “…In contrast to the use of ozone as an initial treatment to reduce microbial populations on produce surfaces, ozone gas has also been investigated for use during storage of various foods, including fish…” Did you know, there is a secondary effect—it removes the fishy odor!
How do you ozonate fish?
As of yet, no official guidelines are in place for ozonation of fish. However, A2Z Ozone, Inc. recommends in our Aqua-6 Operating Manual (Page 8) to treat meat (as well as fish) as you would vegetables—fill your large glass bowl or sink with water, place the diffuser stone 2 to 4 inches deep in the water and operate for 15 minutes (Function #4).
Is there a place for ozone in a fish hatchery or fish farm?
A fish hatchery breeds fish for the purpose of restocking lakes and streams that have been overfished. Fish farms raise fish for human consumption. One of the biggest problems that fish hatcheries and fish farms come across is keeping the hatchery clean. Methods that allow them to do this involve chlorine and other chemicals that cause nitrous oxides to be released. That’s where ozone steps in. Ozone is a chemical-free way to help fish hatcheries supply the oxidizing agents needed without affecting the oxygen supply of the fish. At a hatchery, there is a complex filtering system in place to screen out course solids but it does little for the smaller substances (colloidal) which can float alongside the fish. Nitrate levels that can hurt fish are not put into check as easily, though, and require chemicals to control. And organic compounds that cause the water to appear cloudy are often seen in a hatchery. Ozone can reduce fish disease and stress (according to experts at the Freshwater Institute, Shepherdstown, West Virginia). And don’t forget the germs! While both fish farms and hatcheries can get the benefits of ozonation of the water, they need to use caution because at high levels, ozone can be harmful.
Meet our fish!
I am pleased to introduce you to Charlie Brown, our gold twinbar platy; Snoopy, our glowlight tetra; Linus, our dwarf gourami; and Lucy, our bala shark; Schroeder, our julii cory; and Peppermint Patty, our rainbow shark.
Photo of the fish tank at A2Z Ozone, Inc.
At A2Z Ozone, Inc., we have been experimenting with a 55-gallon fish tank on-site. We started off two months ago with bait fish and graduated to the Peanuts gang when we were confident we had the settings right for these freshwater fish. We use A2Z Ozone’s Aqua-6 Multi Purpose Ozone Generator set on timer function 9—operating for 15 minutes every hour, repeating the cycle every hour—to clean the tank. The members of the Peanuts gang were not in perfect health when we received them—some had fin clamp, were skinny and spotty. The ozone not only produces a clean environment for the fish, it has healed their ailments. I am happy to report that our fish are active, healthy and behave wonderfully. Maybe what we appreciate most is there is no fishy smell to the fish tank—that fish odor even the cleanest of fish tanks brings into a home or office setting. In the two months we’ve had the tank, there has been some need to clean algae growing in the tank, but in these past several weeks our algae problem has also diminished. Join in the fun! Set up your own experimental fish tank. Try the Aqua-6 Multi Purpose Ozone Generator today!
Check out this post to learn more about how the natural properties of ozone can be used to extend the shelf life of fish products.
- Increasing Fish Shelf Life. World Academy of Science, Engineering and Technology 62 2010. Extension of Fish Shelf Life by Ozone Treatment. Behrouz Mosayebi Dehkordi, Neda Zokaie. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.184.9701&rep=rep1&type=pdf
- Sanitizing the Fish We Eat. U.S. Food and Drug Administration. Safe Practices for Food Processes. Chapter V. Methods to reduce/Eliminate Pathogens from Produce and Fresh-Cut Produce: http://www.fda.gov/Food/FoodScienceResearch/SafePracticesforFoodProcesses/ucm091363.htm
- Ozonation and UV Disinfection. Steven Summerfelt & Brian Vinci. Freshwater Institute, Shepherdstown, West Virginia: https://ag.arizona.edu/azaqua/ista/ISTA7/RecircWorkshop/Workshop%20PP%20%20&%20Misc%20Papers%20Adobe%202006/9%20Ozone%20&%20UV/Ozonation%20UV%20Disinfection.pdf
- Fish Hatcheries. NSW Department of Primary Industries Fishing and Aquaculture. Ozone in Recirculating Aquaculture: http://www.dpi.nsw.gov.au/fisheries/aquaculture/publications/water-quality-management/ozone-in-recirculating-aquaculture-systems