Control of Classification Equipment

Manual Reflectance Probes (Hennesey, CGM and Fat-O-Meater)


A hand-held optical probe is used to measure fat and muscle thickness in predefined locations on the carcass of pork.

Based on the measurements a formula is used to predict the total lean meat percentage.

image du cgm

The IM 03 Pig carcass grading apparatus was developed after the end of the EUPIGCLASS project, and has not been tested in the project.

Known standard deviations


Repeatability s(r)

Reproducibility s(R)






Error Sources


Known possibilities for error



Error contribution expressed as standard deviation

Installation of the probe and the functionality of the work place       
Condition of the probe concerning    
-  The size of the knife     
-  The sharpness of the knife     
-  The measuring guide     
-  Linear measures against standard blocks 



Probing sites, place and angels



-  Insertion place


-  Insertion angle


It should be noted / documented which instrument that are used, and for each instrument the program version  or EPROM number should be recorded to make it possible to track the used algorithm.

Daily control

Periodic control

Control of instrument

Control of instrument

  • Check paper in the log printer
  • Morning control of the probe
  • Re-sharpening of the point tip
  • Testing system with the test block
  • Probe, measuring plate, and front plate to be cleaned regularly during the day
  • At the end of each working day the instrument must be cleaned.


Control of data

Control of data





Control of reflectance with test block

Control with standard block


Check of performance of classification


It should also be a requirement that the abattoir checks the performance of classification every day. F.ex. that one person - on behalf of the management - must check 10 pigs (which have been classified) per day per classifier to ensure that the measurements have been taken in the right position (and right angle). As it can be seen in the following pictures, the use of simple tools is enough:




Control with steel square

Check of classification results


It is important that the abattoir several times a day checks that the average meat percentage (and the average fat and meat depths) are as expected compared with other days or other reference data. If it is not the case, the abattoir should make a check of the performance of classification and a check of the equipment.