Meat Hygiene Directive: 2013-28

Ottawa, Ontario
K1A 0Y9

April 04, 2013

Subject: Beef Grading Directive

Guidance to Graders for disagreement with marbling and yield measured by an instrument grading system

To: All Beef Graders under the Agricultural Products Act

Graders service industry with excellence in the application of the Canadian grade standards. The nature of the grade assessment remains subjective and constant measures to enhance consistency are needed.

Instrument grading technology to date is approved to assist the grader through the assessment of marbling and carcass yield, using technology's objective measurements.

Grader correlation session results have shown that humans are less consistent in the subjective assessment of marbling and yield on carcasses that are borderline between two grades, In other words, graders disagree somewhat more between themselves on borderline carcasses than a camera grading system disagrees with its own results or the results of another camera grading system.

The approved technology is quite consistent in its results. This means that the system's yield and marbling measurements differ very little from each other when identical carcasses are measured over and over again. This does not mean that the measurements on one individual carcass are always completely accurate, but it means that over hundreds and thousands of carcasses measured, the measuring errors are small.

This advantage is reduced when hundreds or thousands of carcasses are assessed by graders alone – human factors, subjectivity etc. come into play.

Purpose of the directive:

The beef industry desires yield and marbling assessments to be as objective as possible and concentrate individual grader override on situations where the instrument measurement is influenced by one or more external factors. This allows better comparison of grading results across Canada and between Canada and the US.

Directive:

A grader should limit overriding of marbling and/or yield measured by instrument technology to situations of improper dressing, carcass presentation and remaining grade factors, such as:

  • Sex
  • Age
  • Muscling
  • Fat - colour and texture
  • Lean Meat - colour and texture 

A grader should accept the instrument grade data output for each carcass unless the carcass or image exhibit one or more of the following:

  • Ribbed on a bias (improper ribbing angle)
  • Fat trim or fat pulls
  • Inadequate ribbing depth which will not allow proper camera placement
  • A rib eye surface other than the 12th – 13th rib cross section
  • Frozen rib eyes
  • Blood shot area
  • Bone dust
  • Carcass ID number does not match the monitor carcass ID number
  • Improper camera placement

Camera not used in accordance with manufacturer's instructions (example: instrument calibrated to fully chilled carcasses but measurements are taken on un-chilled or partially-chilled carcasses).

The discrepancy between grader assessment of marbling, or rib eye surface area or fat thickness and the instrument measurements/yield calculations are extreme or would result in a vastly different yield grade or quality grade.

Technology is only a grading tool and the application of an official grade is always under the authority of an accredited grader in accordance with the applicable Act and Regulations.

Parthiban Muthukumarasamy
Director
Meat Programs Division