Slime & bacteria under pressure
TRIO - FTC Sweden says it is now distributing a Japanese, high-pressure cleaning system, the Auto Water Scaler System that it removes fish scales and slime very efficiently.
The thing about bad smells, FTC says, is that it is not the fish but the bacteria, including "Listeria, which are present in fish slime and under the scales of fish. By cleaning the fish with high pressure water jets, it is possible to extend the shelf life of fish and, "reduce the presence of undesirable bacteria by up to 95 per cent".
FTC boss Jan Soderlind writes that, after working in the meat sector, he set up FTC in 1978 and began marketing machinery for fish processing -- from automatic head cutters to hand-held pin boners. Today FTC focus on equipment for salmon and trout but are expanding their range for other fish such as sea bass and sea bream. Target markets include the UK, Norway, the Americas and Japan.
"The problem of high bacteria counts in fish slime aroused my interest a long time ago. They appear not only on the surface of fish but also under fish scales. This has never been a secret. But no one ever seems to have taken this seriously in Europe.
"The fact is, fish is the only meat in which we accept that the raw material (that is, the whole fish) is brought into processing factory without any prior treatment to avoid bacterial contamination.
"When producing, for example, vacuum-packed or even over-wrapped skin-on fillets and steaks, in which no de-scaling has taken place, it does not need much imagination to realise that bacteria still present on the unscaled fish skin have the ideal environment in which to proliferate, thus shortening the product's shelf life.
When fish is not pig
"Compare that with the way in which we handle pork. There are important differences. After the pig is slaughtered, the carcase goes through several stages before it enters the processing unit. The carcase is submerged in a tank of boiling water, followed by flame-searing to end the treatment which eliminates up to 95 per cent of the bacteria present.
"All of this to ensure a good product with a long shelf life. For some reason, the fish-processing industry has [few] of the veterinary controls which the meat industry (in both slaughtering and processing sides) has had since time immemorial. Why are we not so careful in the fish-processing industry?
"Recent field research and laboratory analysis undertaken in Sweden by the Environment Department, shows that many ready-to-eat salmon and trout products on sale in Swedish retail outlets have been found to contain high levels of bacteria. By removing, very carefully, fish slime and scales, without damaging skins, before fish enter the processing unit, we believe that this specific problem could be minimised.
Jet treatment
"The most effective solution is to use high pressure water jets. We have learned a lot of this method from the Japanese, where such products have been used, with considerable success, for many years. Mechanical fish scalers, on the other hand, carry the obvious risk that their abrasive action will create small holes in the skin surface of fish, making easy entry points for bacteria. Of course, the ideal method is to remove slime and scales before gutting. More realistically, most processors will want to buy whole gutted fish, which they will then de-scale before heading, all this to avoid listeria, which can appear in the gills of the fish.
"By removing slime and fish scales from fresh salmon, you can extend its shelf life by up to six days on ice. De-scaled fish are also easier to trim.
"Several UK exporters of fresh and cold-smoked salmon experienced major problems with their shipments to the all-important US market, where tests at ports of entry showed high bacteria counts. Large consignments, in some cases, were refused entry. According to the Scottish Daily Mail, 15 large shipments to the USA market were rejected during 2003, because of high listeria scores.
"A large part of the problem is that we are reluctant to acknowledge what slime really is. Instead of calling it slime, we should call it bacteria, because that is what it is. When fish is delivered to the processing unit, without first removing slime and scales, a lot of things can go wrong. During its transportation, for example, even small changes in temperature can encourage an increase in bacteria. In the unhappy situation of the temperature going beyond eight degrees Celsius, an avalanche-like increase in bacteria will occur. The principle rule is that fresh fish should not 'smell of fish'. If it does, the smell is coming from the bacteria.
Indirect effect
"FTC's Auto Water Scaler System is made in Japan, where about 450 machines have been installed since 1985. The US got its first machine two years ago. Research there, carried out by an independent food laboratory, clearly demonstrated how the Auto Water Scaler System dramatically reduced the presence of bacteria, thus extending shelf life and eating quality.
"Most salmon processors use several suppliers of whole fish. FTC's main strategy is to inform all industry buyers of whole salmon, major retail and food service groups of the fundamental problem. This will enable them to impress on their suppliers the importance of reducing the bacteria present in fish slime and scales before processing begins."
