World catches of fish have increased in the 1970s and 1980s but seem to have stabilized since 1988 to just under 100 million t. As the human population is ever increasing, it means that less fish will be available per caput every year. Nevertheless, a large part of this valuable commodity is wasted: it has been estimated by FAO that post-harvest losses (discards at sea and losses due to deterioration) remain at a staggering 25 % of the total catch. Better utilization of the aquatic resources should therefore aim primarily at reducing these enormous losses by improving the quality and preservation of fish and fish products and by upgrading discarded low value fish to food products. Very often, ignorance and lack of skill in fish handling or in the administration of fisheries are among the causes for lack of progress in this direction.
FAO has long recognized the need for training in fish technology, and since 1971 a series of training courses, financed by the Danish International Development Agency (DANIDA), has been conducted in the developing countries. In 1988 a training manual entitled "Fresh fish - quality and quality changes" was published. This book has been extensively used and is now out of print. This present book is a revised and updated version of the first publication. It still only deals with fresh fish, as it is felt that a solid background knowledge of the raw material is essential for further development in preservation of and adding value to the product. In the context of this book, fresh fish is either fish kept alive until it is consumed, or dead fish preserved only by cold water or ice.
The book describes fundamentals in fish biology, chemical composition of fish and post mortem changes, with a view to explaining the rationale for optimal catch handling procedures and obtaining maximum shelf life. The effect of various factors (temperature, atmosphere, etc.) on fresh fish quality is discussed as are the various sensory, chemical and micro-biological methods for assessing fish quality. Wherever possible, data on tropical fish have been included.
Two new chapters, not included in the first publication, have been added. One is a description of the practical application of new and improved fish handling methods (Chapter 7) and the other is the application of the Hazard Analysis Critical Control Point (HACCP) system in a quality assurance programme for fresh and frozen fish (Chapter 9).
Fresh fish handling procedures encompass all the operations aimed at maintaining food safety and quality characteristics from the time fish is caught until it is consumed. In practice, it means reducing the spoilage rate as much as possible, preventing contamination with undesirable microorganisms, substances and foreign bodies and avoiding physical damage of edible parts.
The immediate effect of fish handling procedures (e.g., washing, gutting, chilling) on quality can easily be assessed by sensory methods. Fish quality, in terms of safety and keeping time, is highly influenced by non-visible factors such as autolysis and contamination and growth of microorganisms. These effects can only be assessed long after the damage has occurred, and the proper procedures must thus be based on knowledge about the effects of the many different factors involved. Large or small improvements are usually feasible when analysing current fish handling methods.
It is hoped that the reading of this book, combined with practical training, will be helpful in providing the stimulus which is often necessary to promote development in fisheries.