Fish preservation methods include:
1. Chilling: Fish is covered with layers of ice for short-term preservation, effectively slowing down autolytic enzyme activity.
2. Freezing: This long-duration method involves freezing fish at temperatures between 0°C to -20°C, inhibiting autolytic enzymes and reducing bacterial growth.
3. Freeze Drying: Fish frozen at -20°C undergo direct sublimation of ice to water vapor at 140°C in a vacuum chamber. The dried fish is then packed or canned.
4. Sun Drying: Inhibiting microorganism growth, this method helps prevent fish spoilage.
5. Smoke Drying: Prepared by burning woods with low resin content, smoke not only destroys bacteria but also imparts characteristic color, taste, and odor to the fish.
6. Salting: Osmosis, facilitated by salt, removes moisture from fish tissues. High salt concentration hampers autolytic enzymes and bacterial activity.
7. Canning: This involves sealing fish in a container, heat sterilizing the sealed unit, and cooling it to ambient temperature for subsequent storage.