There has been a dramatic increase in the fish catch in Thailand since trawl fishing was introduced to Thai waters in the early part of 1960. This increase has been readily absorbed by the market so that fish and fish products are an important and popular item in the diet of the country. Marine fish is mostly consumed in the coastal provinces but with improving communications and the establishment of cold stores in inland areas the demand there is likely to rise. The population of Thailand is increasing by about 3 percent annually and fisheries products will have to make their contribution to the feeding of this extra population.
As well as a rise in the total consumption of fish in Thailand there is likely to be a change in the pattern of utilization. As the standard of living of the population increases there will be an increased demand for more western-type convenience products but so far there is a negligible production of frozen retail packs and canned products have low sales because of poor quality. Traditional processing methods will become relatively less important giving place to more sophisticated techniques.
The research programme of the Fisheries Technology Laboratory will have to take into account these changes in the pattern of supply, distribution and utilization of fish as well as considering present practices.
The research programme recommended by the expert is meant to improve present practices and prepare for future changes in the industry. All the projects outlined cannot be started at once but should be incorporated into the work of the laboratory over the next five years as circumstances permit.
Icing
Icing is the simplest, cheapest and most convenient method for short-term preservation of fish and the Fisheries Technology Laboratory should give priority to a long-term programme of research into its use. The storage life of important species of fish should be determined under the best icing conditions. Most of the publications and recommendations concerning icing of fish have been based on work carried out in temperate countries on fish from arctic or temperate waters but the expert is of the opinion that the storage life of tropical fish will be longer than that of fish from those waters so long as the icing conditions are adequate and the fish is carefully handled. If this can be established it will have important implications for the design of distant water trawlers which may be introduced into Thailand in the next few years.
Changes in the fish during spoilage should be measured by both objective and subjective methods. As well as the determination of basic compounds produced by bacterial action, presently being used by the laboratory, it should introduce the determination of hypoanthine content as an index of quality in the early periods of spoilage. Spoilage rates of the most important species of fish under good icing conditions should be determined and used as base lines for comparison with commercial practices.
The assessment of quality by taste-panel techniques should be further developed, particularly for raw, iced material as an aid to grading fish on the market.
The bacteriology of spoilage should be an important part of this project but further recommendations on this subject will be made by the expert's successor.
Handling at sea
The fish caught by trawlers is not being thoroughly washed before icing and the expert recommends that a simple washing tank should be designed for installation aboard these vessels.
The use of boxes for stowing iced fish is to be encouraged but the Fisheries Technology Laboratory should prepare a code of practice for the guidance of trawler crews, describing the correct way in which this should be done.
The wooden boxes presently used are not properly cleaned after use and the Fisheries Technology Laboratory should investigate the use of plastic or metal boxes.
It is most likely that storage in ice will be adequate for the preservation of the catch on board ship, even if more distant waters are fished, but if total journey times are likely to exceed the limits of icing, research should be carried out in preservation by superchilling or freezing at sea.
Handling during distribution
The present use of large boxes for distributing fish by road and rail contributes to fish spoilage. The pricing regulations of the carriers encourage this practice but the Fisheries Technology Laboratory should investigate the use of smaller plastic or metal containers.
The laboratory should also investigate the use of shelving and pound boards similar to those in trawlers to reduce bruising and crushing of the fish during the bulk transport of chub mackerel.
Freezing and cold storage
At present only a small amount of fish or fish products is frozen but most if it, shrimp and squid, is of high economic importance. Also an increasing amount of vertebrate fish, especially chub mackerel, is being frozen as buffer stock to even out supplies. The freezing equipment and cold stores which the expert examined did not appear to be operated in the most efficient way.
The Fisheries Technology Laboratory should continue the work started by the expert on the examination of the performance of freezing equipment in factories, recommending improvements. It should investigate the cold storage properties of important species of fish and determine the time/temperature tolerances for good quality products. The laboratory should also investigate the use of sodium tripolyphosphate in controlling thaw drip losses from frozen shrimp and squid.
Fermented fish products
The Fisheries Technology Laboratory as well as other research institutes have produced fish sauce but the products do not resemble those made by traditional methods.
It is recommended that basic research be undertaken by the laboratory into the biochemistry and microbiology of both fish sauce, (nam-pla), and fermented fish, (pla-ra), production.
Salted and dried products
The traditional methods of salting and drying are carried out in small manufacturing units more or less as a cottage industry and it will be difficult to exert any technological control over these processes until there is some concentration into larger units. However, processing guidelines prepared by the laboratory could be helpful to the small producers.
The drying of both salted and unsalted fish is mainly carried out by sun drying methods.
The Fisheries Technology Laboratory should continue the work started by the expert in mechanical drying of fish in the Torry kiln. An electricity consumption metre should be fitted to the kiln to enable the economics of drying to be studied.
Mechanical drying will produce fish with a water content lower than the limiting value for suppression of mould growth but on exposure to ambient temperatures and humidity, moisture will be absorbed leading to subsequent spoilage.
The laboratory should investigate methods of packaging in plastic film to reduce re-absorption of moisture. It should also investigate the use of additives such as sodium benzoate and propionic acid to suppress mould growth in unprotected salted and dried fish.
Smoked fish
The Fisheries Technology Laboratory should continue the work initiated by the expert on smoked products on a wide range of fish. The aim should be to develop products for both the home and export markets. The storage life under refrigeration near 0°C and in frozen storage should be studied.
Utilization of trash fish
It is unlikely that any portion of the trash fish catch could be used for human consumption by the usual processing methods. Furthermore, because of its varied and variable nature it would not be suitable for the production of fish protein concentrate as is normally understood by this term but it would be possible to extract the protein by acid or alkali or one of the other enzymatic methods which have recently been described. The protein in solution can be recovered as a pure preparation and would be suitable for incorporation into the prepared foods developed by Kasetsart University, Bangkok.
These techniques are only in the development stage in advanced countries but because of the importance of utilizing the large trash fish catch for human consumption, the Fisheries Technology Laboratory should keep these developments under review and adopt a suitable process to trash fish.
Canning
The expert was not able to do any work himself on canning of fish due to the lack of equipment. There is no doubt that suitable, very fresh, raw material is available for excellent canned products. The canned fish currently produced is of poor quality both in terms of the contents and the can because of inadequate technical knowledge and control in the factories.
The laboratory should develop high quality canned fish and products for the export market, and should also develop a variety of sauces for filling the cans with something different from the usual tomato sauce.
Processing of chub mackerel
Chub mackerel is the only species which is caught in large quantities and is fish of excellent eating quality and high nutritive value. Because of its high fat content at some seasons of the year, its processing properties are sufficiently diverse to warrant a separate research programme. The supply of chub mackerel is very variable both monthly and annually and it is good economics to freeze some during times of glut in order to even out supplies to the market. Unfortunately if the fish is not correctly frozen and stored, considerable oxidation of the fat will occur.
Research into icing, handling and freezing of this species will be included in the programmes recommended in earlier sections but the laboratory should undertake investigations in the oxidation properties of the oil from chub mackerel.
It is likely that the temperature of stores used holding frozen chub mackerel are not low enough and priority should be given to the storage properties of chub mackerel in programmes concerning frozen fish. The laboratory should produce a code of practice on the freezing of chub mackerel and attempt to establish a quality control programme in industry.
In view of the large and increasing catch of fish and the importance which must be attached to its effective utilization, the expert recommends that the Fisheries Technology Laboratory should urgently receive additional staff and equipment. It should recruit as soon as possible graduates in microbiology and mechanical engineering.
Further recommendations concerning the microbiologist will be based on the work of the expert's successor.
The engineer is required to study and advise on handling at sea and during distribution and also to advise on the design and operation of freezers and cold stores. He will also be responsible for the operation and maintenance of the laboratory's freezing and cold storage equipment.
A graduate with experience in biochemistry should also be recruited at a later date to study the biochemical problems of fish spoilage, protein extraction from trash fish and the manufacture of fermented products. Some extra scientific assistants will need to be recruited to carry out routine work.
The most urgent equipment requirement is chilling and freezing facilities. It is recommended that a chill room capable of storing iced fish in boxes or in bulk be constructed. This room should be capable of maintaining temperatures at a little below 0°C if required so that work on superchilling can be carried out. There should also be one or preferably two cold rooms capable of maintaining temperatures down to - 30°C. The Fisheries Technology Laboratory will also need freezing equipment and it is recommended that both air blast and horizontal plate freezers be obtained as circumstances permit. Outside technical assistance should be sought to advise on the specifications and design of these facilities.
It is recommended that the provision of a small flake ice machine for the use of the Fisheries Technology Laboratory be made, particularly if the research programme requires special ices. A pilot scale canning plant should also be obtained for the development of new products.
Experiments should be carried out at sea but the work would not justify a vessel for the sole use of the laboratory at the present time.
It is also recommended that a commercial vessel be hired for this purpose or arrangements be made to obtain facilities on research vessels operated by the Department of Fisheries.
A report on processing and quality control of shrimp and squid was prepared by the expert while in Thailand and distributed to persons in industry and official circles concerned with quality control. A summary of the recommendations it includes is given below:
Quality control of frozen shrimp and squid should be by end product before shipment.
Specifications for the quality standard should be based on the United States schedule.
The advice of the expert's successor should be taken in drawing up the bacteriological standards.
The Fisheries Technology Laboratory should collect data on the production and levels of quality in the industry before the final standard and sampling levels can be drawn up and further technical assistance should be obtained at that stage.
The Fisheries Technology Laboratory should be responsible for initiating the quality control scheme and recruiting and training the extra staff required.
When the scheme is in routine operation the Fisheries Technology Laboratory should be relieved of the responsibility for its operation though still providing technical advice to the shrimp processing industry.
There will have to be an improvement in the handling, icing, processing and freezing of the shrimp. Metal or plastic boxes should be used for icing shrimp both on board the vessel and during distribution. The general hygiene of the factories will have to be improved and packing and weighing must be more carefully controlled. More attention must be given to the operation of the freezers and stores to ensure that freezing times are short and the products are kept at a low and constant temperature.
The industry in cooperation with the Fisheries Technology Laboratory should experiment with different ways of packing the shrimp before freezing as an alternative to the use of the metal containers.
Sodium polyphosphate should be used to control thaw drip losses.
Each processing company should appoint one of its managerial staff to be responsible for the quality of its product and this person must have some technical training.
The level of technical knowledge in the fish processing industry is very low and the Fisheries Technology Laboratory should increase its work on extension services. An Information and Liaison Section should be set up which should receive relevant journals and abstracts in fish processing technology and advise the industry of new developments in fish processing.
The laboratory should hold training courses for personnel in the industry and issue codes of practice and other advisory literature for guidance. It should also extend its work of visiting and examining processing factories and advising the managers on improvements in their methods.
The technical assistance which has already been planned for the year through July 1971 should be continued after that date. It is recommended that technical assistance should be obtained on the engineering aspects of freezing and cold storage. It is important that the engineer recruited to the Fisheries Technology laboratory is already acting as the counterpart when the expert arrives and that suitable equipment is available at that stage. Apart from working as a counterpart this engineer should receive further training abroad.
The expert has initiated work on quality control of frozen shrimp but further technical assistance will be required after the laboratory has completed some preliminary work and while the final specifications and sampling plans are being drawn up.
One of the Laboratory staff should receive training abroad in the measurement of quality of iced fish by both laboratory and taste panel methods.
