VIBREX IN THE AQUACULTURE INDUSTRY
TOTAL VOLATILE NITROGEN
We all recognise the typical smell of fish and shrimps being sold in the markets but what most people do not realise is that the smell is a result of the fish and shrimps rotting. One method of measuring the degree of degradation or spoilage is to determine the Total Volatile Nitrogen value (TVN) which is based on the ammonia produced by the degradation of the protein. A fresh fish or shrimp when harvested from the sea, ponds or cages has a TVN of 4 to 7. As the TVN increases (due to the protein in the fish/shrimp degrading), the smell increases. In Europe, in general, a TVN value above 50 will require chemical conditioning of the fish before it can be supplied for human consumption. If the TVN value is above 100 it is considered not fit for human consumption and can only be used as pet (cat or dog) food. Fish or shrimp harvested and stored in ice containing Vibrex will have a TVN of about 17 and there is virtually no smell!!
Vibrex controls all bacterial, enzymatic and chemical degradation of the fish or shrimp because it releases chlorine dioxide in acidic conditions. Acid conditions are caused by the bacteria themselves (i.e. degrading/decomposition of the fish or shrimp) and the degradation is very quickly stopped because the bacteria are killed by the chlorine dioxide produced. Vibrex enables aquaculture farmers and fishermen to deliver their fish and shrimps of the best quality, highest value, and longest shelf life to the market.
Vibrex can be used in many different applications within the aquaculture industry.
FISH AND SHRIMP FARMING
It has been shown that a treatment of up to 3mg/l of continual dosing of chlorine dioxide does not have any adverse effect on the water salinity, pH, alkalinity, dissolved oxygen and on the phytoplankton (Skeletinema costatum and Chaetoceros calcitrans). Vibrio has been demonstrated to be eliminated with a dosage level as low as 0.5mg/l. A dosage of 1.5mg/l will eradicate the white-spot virus (WSV], a double stranded DNA virus) with a retention of 1 to 1.5 hours of residual effectiveness. The Yellow Head virus is similarly eradicated at a dosage level of 1.5mg/l for 2 to 3 hours.
In order to maintain a residual of ClO2, the ClO2 concentration should be monitored by a simple colorimetric method (LaMotte or Hach) or similar testing method once a day. Further Vibrex additions will only be necessary as indicated by these test results. As an example, if the initial dosage level is 3mg/l in the morning and after 24 hours the residual has dropped to 2.5mg/l, then an addition of 0.5mg/l will be necessary. The residual should be monitored every 24 hours. If the pond has disease present, monitoring should take place every 3 hours and the residual ClO2 should be maintained until the disease problem begins to abate. A dosage of 6mg/l and in excess of 10mg/l may adversely affect the phytoplankton.
Vibrex can be used to sanitise ponds that are free of fish and shrimps and associated equipment. Before sanitising, the fish and shrimps must be removed from the pond. The pond and channels can be sanitised by applying a solution of 250mg/l of ClO2 in water. Equipment such as incubating equipment and nets should be soaked in water also containing 250mg/l of Vibrex for at least an hour with some agitation.
Vibrex when used in the fish holding tanks of fishing vessels, disinfects the tanks, prevent degradation of the harvested fish and eliminates any risk of Listeria. The Vibrex can be used in conjunction with the vessel’s RSW (recirculating chilled seawater) system if the vessel has one, or added to the water used to make the ice to store the fish in. The use of Vibrex will help ensure that TVN levels are less than 30 and the use of Vibrex allows fishing vessels to stay out longer and still bring home fish with low TVN values making the catch easier to sell with a potentially higher market value.
Vibrex can be also used in conjunction with ice used to store the fish and in the wash water during processing of the fish to minimise any associated degradation. Vibrex ensures proper sanitation so there is no cross contamination of listeria occurs and ensures that the fish used in the manufacturing of fishmeal is of the highest quality with no harmful residuals.
FISH AND SHRIMP PROCESSING
Vibrex should be dosed into all process water that comes into contact with the fish or shrimps either in the factory or in the case of farmed stocks also at the point of harvest; thus minimising any degrading effects. Vibrex should be added to the water used to make ice used to store the harvest both in pre and post processing. As the ice melts, the Vibrex is released slowly to ensure a continual attack on any degrading bacteria or biochemical reactions, and control the harvest quality during transit and all the way to the customer.
For produce such as mussels, clams, and cockles, there is the need for depuration to remove bacteria, virus and other toxins. Vibrex can be used in the depuration tank water to rapidly kill any bio-contaminates, enabling a better and safer product to be delivered to the market.
When Vibrex is used in the washing and shucking process, scallops will maintain the highest quality and have an increased shelf life. As an additional benefit, they will have an appearance and texture far superior to competitor products not using Vibrex.
Vibrex is also a very powerful and effective cleaner/ sanitiser that can be used everywhere there is a requirement for clean and sanitize equipment, tools, and working surfaces.
Dr Frank Wilson
Exclusive Distributor for Oxynova and Vibrex in Brunei Darussalam,
Malaysia, Gaum & Micronesia and the Maldives
Tel: +6016 888 2481, Email: Drwilsonf@yahoo.com.au, Skype: frank2481