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THE EFFECT OF VIBREX ON TVN VALUES AND FISH QUALITY

The correct use of Vibrex can virtually eliminate the rotting of fish and shrimps. Please contact us for assistance which will improve the quality of your fish and shrimps and substantially extend their shelf life.

Its easy with Vibrex!



Introduction

When we go to the fish market, we all know the distinctive smell of the fish for sale there as well as the overall odour of the entire market. What we do not realise is that the smell is actually the smell of rotting fish. Degradation or spoilage begins as soon as the fish dies. Their normal life supporting defense mechanisms stop working and a series of bodily changes begin that cause spoilage. These changes are caused by bacteria, enzymes and chemical action. All of the changes that cause seafood spoilage are directly affected by temperature. High temperatures speeds up tissue spoilage and low temperatures slow it down. For many seafood species, increasing the temperature from 0oC to 5oC doubles the rate of spoilage and cuts the usable shelf life in half.

Overall sanitation practices in the handling of seafood are also important. Contamination of seafood by bacteria from dirty ice, dirty water, dirty containers and dirty surfaces can increase bacteria concentrations on seafood and speed up the rate of degradation. Contamination with food poisoning type bacteria can also cause serious illness, and sometimes death when the seafood is eaten. By keeping seafood handling and storage equipment clean reduces bacteria contamination and slows the rate of spoilage.



Total Volatile Nitrogen

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 fish protein. A fresh fish when harvested has a TVN of 4 to 7. As the TVN increases (due to the protein in the fish/shrimp degrading), the smell of fish increases. In Europe, in general, a TVN value above 50 will requires 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 caught and stored in ice containing Vibrex will have a TVN of about 17 and there is virtually no fish smell!! Fishermen find that by using Vibrex that they have 20% less wastage and get a better price for their fish when they reach harbour fish markets.

Vibrex can be used for a number of critical sanitation areas onboard fishing vessels with amazing results. The landed catch, whether it is fish or shrimps or other seafood, will be fresher and higher quality when off loaded. Vessels having an RSW (recirculating chilled seawater) system can stay out at sea longer and still bring home a better quality catch than those vessels not using Vibrex. By using Vibrex as directed, TVN levels are consistently maintained at less than 30 and often around 17.

Areas of Fish Degradation (Spoiling)

There are four areas of fish degradation:
1. Immediately after harvest whilst in the RSW system or in ice on the fishing vessel
2. During transport in ice from the port to the factory
3. In storage and in ice prior to processing
4. After processing/packaging and available to the open markets

Fish Storage Options

When the fish or shrimps are stored in ice, the ambient temperature is about 2 to 5oC, whereas, degradation still occurs; albeit more slowly. Vessels utilising RSW systems maintain the water temperature at 0o C or lower. The addition of Vibrex to the water used in ice making will significantly reduce the amount of degradation that may take place in the stored seafood. An RSW system on a vessel is certainly more effective at reducing fish degradation than the use of only ice.

An untreated RSW system will have residual bio-films, slime and bacteria in the system. When using Vibrex for the first time, there are two options that are available to address this issue:

1. Operate the system with Vibrex for approximately 5 to 10 hours and then discard this cleaning water. Refill the system with new water and add Vibrex to the RSW system once again to be used during the fishing harvest/storage/transport period.
2. Or add twice the normal directed quantity of Vibrex during fishing operations.



Dr Frank Wilson
Exclusive Distributor for Oxynova and Vibrex in Brunei Darussalam, Malaysia, Guam & Micronesia and the Maldives
Tel: +6016 888 2481, Email: Drwilsonf@yahoo.com.au, Skype: frank2481