Measurement of Product Samples

Having ensured that the Fatmeter is operating correctly you can now proceed to the measurement of product samples…

It is extremely important to follow the instructions on the Measurement Instruction Chart supplied for the fish you intend sampling. Here is a quick check routine…

  • You have chosen the correct fish calibration.
  • You have checked to ensure that the fish product is indeed a natural fish product, free of additives and other additions.
  • Select the fish samples at random from the batch. Where you are measuring smaller whole fish, eg. Sprat, Sardine, Small Herring, Small Mackerel, etc., then the samples should be grouped according to size.
  • For best accuracy always follow the measurement recommendations on your Measurement Instruction Chart
  • Temperature of the fish to be measured should be between 0 – 10°C, with no ice crystals present in the samples.
  • Ensure that the sensor is placed firmly against the skin of the fish, thus ensuring that there are no air pockets between the sensor and the sample to be measured.
  • It is normal to experience variability in the individual readings. When taken at different parts of the fish.
  • For the most accurate results eight readings should be taken, as recommended on your measurement instruction chart for that species of fish. The object is to obtain readings that are truly representative of ALL of the sample. This will ensure the greatest accuracy.
  • The data is stored within the fatmeter for later downloading to PC, via software supplied by Distell.

Preparation of product samples for sending to Laboratory…

It is important that ALL of the fish to be represented by the fatmeter measurements is packaged, and sent to the laboratory for the analysis. The sample should be stored in a sealed polythene bag immediately after measurement. This will ensure that the sample does not dehydrate, and that there is no drip loss from the product sample.

Here is a quick checklist for the laboratory…

  • Whole carcass, fillets, or sections of the fish, should be received at the lab, properly packed and sealed.
  • The fish sample should be skinned, the head, tail, fins, and belly wall mucus should be removed from the sample. In the case of fillets the fat depots at the Dorsal Fin, and Anal opening should be removed. It is important to retain ALL of the remaining flesh of the fish (including any free oil) for blending, ensuring that any drip loss is included in the blended sample.
  • The sample should be blended, so as to create as homogenous a sample as possible.
  • The laboratory personnel MUST take THREE samples of product from different parts of the blend for the chemical analysis. This will illustrate the homogeneity obtained by the blending process.
  • The average of the laboratory triplicate analysis should be compared with the triplicate readings taken using the Fatmeter.
  • They should compare favourably to accuracy claims in Handbook.

If the results do not compare favourably…

Check the Fatmeter use, as follows…

  • Has the correct calibration been used on the Fatmeter
  • Has the Fatmeter been checked on the Check Pad
  • Is the operator proficient in the use of the Fatmeter
  • Is the fish sample truly within the specification of the Fatmeter calibration being used
  • Check the product for species identification, measurement technique, size, and preparation
  • Analytical method being used
  • Sample preparation is OK
  • Three samples, from differents parts of the blend have been analysed

If, after these checks there is still a significant difference, please contact Distell for advice and help.