kelolalaut.com - The physical method of quality evaluation involves the use of mechanical devices or instruments.  Here are instruments that can be used :

• The clock and thermometer. The quality is affected by bacteria and enzymes, which are highly dependent on temperature and time. So the clock and thermometer are the two most important and commonly used physical instruments in any fishery industry.
• PH-meter. PH of fish gives valuable information about its condition. Measurements are carried out with a pH-meter by placing the electrodes either directly into the flesh or into a suspension of fish flesh in distilled water.
• GR-Torrymeter. Electrical properties of skin and tissue change after death and expected to provide a means of measuring post mortem changes or degree of spoilage. GR-Torrymeter is the instrument used to measure electrical properties.
• Penetrometer.  Texture is an extremely important property of fish muscle, whether raw or cooked. Fish muscle may become tough as a result of frozen storage or soft and mushy as a result of autolytic degradation. Texture can be measured by instrument penetrometer.