Seafood Services Japan - Testing Quality

Welcome to the website of Seafood Services Japan (SSJ) ***** Please excuse the fact this new site is currently under-construction***** Much more than an importer-exporter SSJ acts as an agent for its suppliers in and out of the Japanese market and provides a range of services both up and down the supply chain. Read on to find out more about the company and how we raise the profile and competitiveness of our suppliers and customers. But first can you tell me….. Which of these two fish is better than the other? Does it matter much? Well on Friday the 5th of January, 2001 a single 202kg bluefin tuna, caught in the Strait of Tsugaru off Aomori Prefecture, sold for 20.2 million yen at the Tsukiji Wholesale Market in Tokyo, Japan -that’s US$175,000. This was the auction price paid by a single wholesaler – he still had his commission to add, as did the restaurateurs! Was it just a moment of madness? What made this fish so valuable? What is the difference between a ‘good fish’ and a ‘bad fish’? Can we measure these differences? If the same fish had not been killed using the “ikijime” method, if it had struggled on the deck of the boat, if it had been dropped from a crane, and if it had not been shipped to the market in a constant low-temperature environment would it have still been worth the same value? At about $1,500/hr this bluefin tuna would possibly have been the fastest depreciating item in world history! Anyway, back to the question, which is better????? OK. What if we set up a digital camera and a constant luminescent torch at a pre-determined distance and angle and take a digital image of the tail cut of each tuna. So we end up with these images – does this help? Which is better – left or right? What can we do to help us? What information can we extract from these images? Well if we use off-the-shelf imaging software we can extract values for red, green, and blue - the three primary colours (RGB). So let’s take a look at the RGB values from a particular region of the tail cut from each tuna as shown below. The tuna image on the left gave us R, G, & B values of 125, 65, 48, and the tuna on the right gave us values of 139, 72 and 39 respectively. So what does this mean? We know redness is important in the assessment of sashimi grade tuna. What if we express these numbers as a ratio of red to the other colours? So let’s divide the red value by the sum of the green and blue values. Using this we get 1.10 and 1.25 for left and right tuna respectively. Does this help? Not really. Do we need to spend years on the markets before we can tell which tuna is better? OK. Let’s ask an expert - Mr. Murakami. He’s been selling tuna at the Tsukiji Central Wholesale Market for over 20 years. Let’s ask him to grade the tuna’s quality using either an A, B or C grade – A being the best and C being the worst. Well according to Mr. Murakami the tuna on the left is a C and the tuna on the right is an A. So the tuna with a higher RGB ratio (1.25) is an A and the tuna with the lower ratio (1.10) is a C. That’s interesting. What about a second opinion? Well rather than ask more people let’s see what these men think – or more to the point – what their wallets think. These men have been buying tuna at auctions at the Tsukiji market for a combined number of years that measure in the hundreds. At the auction the tuna with a 1.25 RGB ratio sold to one wholesaler who bid 3500 yen/kg for it, and the tuna with a 1.10 RGB ratio sold to a wholesaler who bid 2800 yen/kg for it. So there you have it – the tuna on the right is ‘better’ than the tuna on the left according to the experts and the digital ‘eye’. Interesting result yes? Well that was just once. How about we do this for a whole year with hundreds of fish…. Amazingly it appears there is a relationship and that my digital eye didn’t fluke this. In the graph below you can see that A grade fish according to Mr. Murakami had higher RGB ratios than B or C grade fish. Also, according to all the wholesalers that bought fish in this year, they thought fish with a higher RGB ratio and ranked high by Mr. Murakami were worth paying more for – of course this was without them knowing either prior to the auction. The above is an example of some of the research conducted within the Aquafin CRC by Alistair Douglas of SSJ on behalf of the Southern bluefin tuna farming industry located in Port Lincoln, South Australia. The finding highlighted the potential of using digital camera technology to rapidly and non-destructively assess the quality of the flesh of farmed Southern bluefin tuna according to the experts that buy it at its main market in Japan. So how do you measure quality? If you work in the seafood industry how do you measure the quality of the product you produce, handle or sell? If you are a fisher, how do you preserve quality? If an aquaculturist, how do you enhance quality? Indeed, what does ‘quality’ mean in the context of your product and what qualities do your customers want and how do you provide them? What are the intangible qualities of the product – the feelings of safety, security, and sense of ‘goodness’ when buying and consuming your product? Along with its collaborators, it is these challenges that SSJ strives to address. SSJ works with not only premium producers committed to continual improvement, but also with like-mined service providers within the supply chain. Through SSJ’s provision of Safety Testing & Quality Measurement, Cold Chain Management, Traceability, Customer Support Services, and Marketing and Promotions the company not only manages information but we also generate it too. We offer seafood producers a gateway to their customers and help them to continually define and meet their customer’s needs, and, in so doing, improve the reputation, competitiveness, and profitability of the producer. Please read our other sections to find out what makes SSJ different and how we achieve the above. Yours truly, Alistair E. Douglas Managing Director, Seafood Services Japan

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Frozen Tuna price doubled - venkym1@gmail.com

Alert - Frozen Tuna price - see power point presentation of tuna_549.ppt by clicking the review link below:

Frozen Tuna price: tuna_549.ppt

Review of Global Tuna Trade and Major Markets

Assay For Histamine in Tuna

Blackwell Synergy - J Food Science, Volume 59 Issue 3 Page 517-518, May 1994 (Article Abstract):

Copper Chelation Assay For Histamine in Tuna

• ¹Authors Beteman, Eldridge, Wade, and McCoy-Messer are with the Dept. of Chemistry & Biochemistry, Univ. of Southern Mississippi, Hattiesburg, MS 39406–5043. Authors Jester and Mowdy are with the FDA Gulf Coast Seafood Laboratories, Dauphin Island, AL 36528–0158.

We thank Dr. Magot Hall for encouragement and helpful comments on the manuscript. We also gratefully acknowledge the aasistance of Drs. Diane Fairclough and J.T. Johnson with the statistical anlyses.

This work was supported in part by a grant from the National Marine Fisheries Service NA16FD0153 to RCB and by a Patricia Roberts Harris Fellowship to J.M-M.

ABSTRACT

A reported copper chelation method for histamine determination was modified for use in decomposing yellowfin tuna steaks. The assay consisted of histamine extraction with hot methanol, purification by rapid cation exchange chromatography, and addition of copper and a dye to the purified sample to form an easily visualized red complex with the histamine. This method detected histamine in the low mg% range in yellowfin tuna steaks with an accuracy comparable to the standard fluorometric histamine assay. It is an alternative to the standard assay when a visual test is desirable or a fluorometer is not available.

Practice of HACCP to prevent histamine in tuna and other seafoods

4-6 Industry practice of HACCP to prevent histamine in tuna and other seafoods

Industry practice of HACCP to prevent histamine in tuna and other seafoods

R. L. COLLETTE, Food Regulatory Affairs, National Fisheries Institute, 1901 N. Fort Myer Dr., Ste. 700, Arlington, VA 22209

Histamine, a causative agent of scombroid poisoning, is formed as a result of time/temperature abuse of certain species of fish. Tuna, belonging to Scombroid fish species, is under the tight scrutiny of the FDA for the occurrence of histamine, a chemical hazard defined by the FDA. Under the new HACCP guidelines established by the U.S. FDA, fishery products containing histamine above 5 mg/g fish is subjected to reject or recall, making serious economical impact on the industry. Tuna is the most consumed fish in the U.S. as in canned products. Tuna industry has undergone rigorous reform to improve the safety of the products with the adaptation of the new HACCP program. Although monitoring histamine at each handling and processing step is a critical step in tuna industry, histamine levels at the receiving points continues to be the main critical point assuring safety of tuna products. Rapid chilling of fish immediately after death to the internal temperature below 50°F (10°C) or less within 6 to 9 hours of death depending on the size of fish has been the most commonly used strategy for preventing the formation of scombrotoxin, and the practice has proven to be effective as the incidences of histamine is substantially reduced since the adaptation of HACCP.

Fishing Kaki Forum :: View topic - Bleeding Fishes

Bleeding a fish


The bleeding of fishes is done to preserve the quality of the fish meat. This is most evident with tuna-like species which has a higher than normal body temperature than the other species due to the active behaviours of the fish. Actual body temperature depends on fish size, the extent to which the fish struggled during capture, and water temperature. Decomposition or spoilage is caused primarily by the chemical breakdown of the flesh by enzymes produced by naturally occurring bacteria. This spoilage process is faster at higher temperatures and proceeds more rapidly in warm tunas than in cold-blooded fishes.

Thus to preserve the fish meat quality, one would have to land the fish quickly and prevent it from struggling too much. When gaffing fishes for food, always aim for the head or the lower jaw so as to prevent damage to the flesh or contamination. Also keep the fishes in a single layer.




Stunning. Stun the fish immediately after it comes on deck to eliminate scale loss and bruising. It is easier to stun the fish when it is still on the gaff or the hook remover. Club the fish with a modified bat, mallet, or lead filled steel pipe on the soft spot right above the eyes.

Brain Spiking (optional). Another option is to immobilize the fish immediately after, or instead of stunning, by destroying the brain. (Spiking the brain is a required procedure for production of sashimi grade tuna worldwide.) In addition to immobilizing the fish, brain destruction helps stop the production of heat and acid, and the loss of energy rich compounds.

To spike a fish, position yourself so that you are balanced with the fish positioned on its belly, and the spiking tool (an ice pick or a sharpened screwdriver) firmly in one hand and the fish's tail in the other. Do not attempt spiking without complete control of your balance, the spiking tool, and the fish. Place the spike at the soft spot above the eyes at a 30 degree angle to the horizontal. Push the spike quickly into the skull maintaining the 30 degree angle while holding the tail with your other hand. Move the instrument from side to side to destroy the brain. The fish will shudder, all the muscles will flex, the mouth will open, and the pectoral fins will flare. After one or two seconds the fish will go limp if done properly.

If not done properly, the fish can shudder violently creating the potential for personal injury, and further scale loss and bruising to the fish. With slippery conditions this procedure can be a challenge, but after several attempts brain destruction is swift and thorough.



Bleeding. Bleeding improves the appearance of uncooked tuna loins and may help initially to reduce fish temperature on deck. It is essential for sashimi grade fish. Fish should be bled for 10 to 15 minutes after stunning (brain spiking) and then immediately chilled. Bleeding is most efficient when done immediately after the fish is landed, and when the heart is left intact to take asvantage of its pumping action. If possible, orient the fish head down and spray with water to prevent clotting. Bleeding can be accomplished in at least three ways; use the one easiest for you. If one cut does not produce blood, try one of the other methods. Using more than one cut may promote more efficient bleeding.

Pectoral Cut: This cut is the most common in tuna fisheries worldwide. With the fish on its side measure 1.5 to 2 inches (about the width of two fingers) from the base of (under) the pectoral fin along the midline. Make a shallow cut about 1/8 to 1/4 inch wide and 1/4 inch deep along the raised ridge near the midline using a clean, sharp knife with a narrow blade. If this cut is made too deep or too wide, usable flesh can be destroyed and reduce the fish's value. Flip the fish over and repeat the cut on the other side. We found this cut to be very effective with albacore.



Gill Cut: The gill arch cut is the one most commonly used. With the fish on its side, lift the gill cover and sever the gill arch and/or insert the knife behind the gill through the gill membrane, and cut up toward the spine, severing the blood vessels at the top of the gills.





Throat or Nape Cut: This cut involves cutting the blood vessel between the heart and the gills. It can be done in either of two ways, depending on the preference of the buyer. With the fish on its back or side cut the "V" shaped nape between the gill covers and the body of the fish to the artery just below the surface. An alternative that leaves the head firmly attached to the body is to make a shallow cut just inside the point of the "V" of the nape, lift the artery with your finger, and cut. The heart is about three inches behind or inside the point of the "V". Take care not to sever the heart or you will loose the pumping action the heart provides. We recommend finding the heart and the artery running between the heart and the gills in your first fish or two, and find what is easiest for you.

Chilling fishes

Chill fish first in slush ice, a mixture of two parts ice and one part seawater before icing. Fishes will cool four to five times faster in slush ice than on ice because the fish are completely surrounded by the chilling medium, and the rate of heat transfer in a liquid is about 25 times faster than in ice. The slush ice tank should be insulated, with a tight fitting, insulated lid, and maintained so that ice is always present. This will require that ice be added periodically depending on catch rates, weather conditions, and the extent of insulation. Add fish to the slush ice tank as they are landed - not all at once. In addition to a substantial loss of shelf life and quality that result from fish left sitting on the deck, slow, inefficient cooling will result from overloading the chilling system.

A mixture of 2 parts ice and one part seawater will maintain a temperature of 0°C. Because fish begin to freeze at temperatures below this, there is no risk of partial freezing and related quality loss.

Ice and freshwater will tend to float on the surface of the slush ice mixture, creating sharp temperature differences, even in a shallow tank. Warm temperature pockets can also become trapped between fish. Agitate the mixture periodically with a pump, by bubbling air in the tank, or manually with a paddle to minimize these potential problems.

Transfer the fish to ice storage when the backbone temperature reaches 10°C and continue to cool the fish to 4°C or below. Holding fish in slush ice for more than 12 hours may lead to excessive water absorption and bleaching. Proper management of the chilling system requires that the internal temperature of the fish be measured periodically throughout the fishing trip. This can be done simply by using a piercing probe meat thermometer, available through most refrigeration equipment suppliers. There are also a number of digital, battery operated, piercing probe thermometers available on the market. When measuring the temperature place the probe close to the backbone on one side of the fish about two inches behind the pectoral fin (the thickest part). After some experimentation, the proper chilling times can be determined for certain slush ice mixtures, fish sizes, loading density, etc.

How you ice your fish after they are removed from the slush tank varies by vessel. If possible, ice fish in single layers in each available bin. Before adding a new layer of fish, gently pack down the ice with a shovel to eliminate any air pockets that may have formed. Cover each bin with an ice blanket. The amount of ice required to chill fresh tuna will vary with a number of factors such as the length of the trip, catch rate, and the extent of insulation in the fish hold and the slush ice tank. In general, proper chilling will require about two pounds of ice per pound of tuna. Each operator must determine the amount of ice they require based on vessel characteristics and fishing pattern.


Info taken from Recommendations for On Board Handling of Albacore Tuna

PS : Please forgive the lousy sketching, I did it by hand and hopefully it should serve it's purpose to help identify the locations better. The gill pictures were taken from MEER