Measuring the protein quality of foods

Learn about Health Canada's position on the acceptable methods for measuring protein quality in food products.

On this page

• Health Canada's position on measuring protein quality in foods
• Conversion factor
• Regulatory modernization
  • Update: Proposed amendments to the Food and Drug Regulations

Health Canada's position on measuring protein quality in foods

The Food and Drug Regulations (FDR) currently require the protein efficiency ratio (PER) method be used to measure the protein quality of foods. It is Health Canada's position that acceptable methods for accurately measuring the protein quality of food products include both the:

• protein efficiency ratio (PER)
• protein digestibility corrected amino acid score (PDCAAS)

Effective immediately, Health Canada (HC) and Canadian Food Inspection Agency (CFIA) will accept results from either PER or PDCAAS methods to show compliance with all* protein quality provisions in the FDR.

Both methods will be accepted given the:

• government's regulatory modernization agenda
• long-standing stakeholder concerns with the limitations of the PER method
• international scientific and regulatory community consensus supporting the use of PDCAAS

* The only exception is for infant formulas, which continue to require use of PER.

Conversion factor

To calculate the protein rating (PR) as specified in Method FO-1, October 15, 1981 using PDCAAS, you should use a factor of 2.5 to convert PDCAAS values to estimated PER values.

Figure 1 - Text description

This figure shows the equations for converting PDCAAS to an estimated PER, and calculating the PR using the estimated PER.

There is a white rectangular box outlined by a thin black rule.

Centered at the top of the box is the equation for converting PDCAAS to an estimated PER in black, bold, mixed-case font. The equation contains the words "PDCAAS for food multiplied by 2.5 equals estimated PER for the food".

Centered at the bottom of the box is the equation for calculating the PR using the estimated PER in black, bold, mixed-case font. The equation contains the words "PR equals estimated PER for food multiplied by grams protein in a reasonable daily intake of the food".

Regulatory modernization

The Agri-food and Aquaculture Regulatory Review Roadmap was published in 2019 to support innovation and economic growth in the agri-food and aquaculture sector. This roadmap identifies a number of initiatives to modernize regulations. This includes a commitment by HC to ensure that the list of scientific methodologies used to determine food safety and quality can be rapidly updated in response to emerging science.

As part of this commitment, HC is working to amend the FDR to allow the use of both PER and PDCAAS methods for measuring the protein quality of most food products. In the interim, HC and CFIA will accept results from both PER and PDCAAS methods until the FDR are formally amended.

Update: Proposed amendments to the Food and Drug Regulations

On November 4, 2023, Health Canada and the Canadian Food Inspection Agency pre-published in the Canada Gazette, Part I the Regulations Amending Certain Regulations Concerning Food Additives, Compositional Standards, Microbiological Criteria and Methods of Analysis. The proposed regulations include amendments to enable the use of the PDCAAS method to measure the protein quality of foods. To learn more about this regulatory proposal, please go to Consultation on the proposed Regulations Amending Certain Regulations Concerning Food Additives and Compositional Standards, Microbiological Criteria and Methods of Analysis for Food.