On May 31, 2025, Canada’s new Biocides Regulations come into force, replacing earlier guidance documents with a more robust, unified framework for evaluating biocide performance. In a series of articles, we compare the previous 2020 efficacy guidance with the new efficacy requirements for biocides, highlighting what has changed and what it means for manufacturers.
Efficacy Requirements:
- Good Laboratory Practice (GLP) and Alternative Standards
The new guideline strongly emphasizes performing efficacy tests under Good Laboratory Practice (GLP). At the same time, it remains open to accepting internationally recognized standards (such as ISO) when accompanied by a clear rationale outlining any differences from GLP standards. This ensures that data quality and reproducibility are maintained while providing flexibility for innovative testing approaches.
- Defining Lower Certified Limits (LCL) and Upper Limits for LCL
While the previous guideline was referring to “U.S. EPA-specified lower certified limit”, the new guidance defines both Lower Certified Limits (LCL) and an Upper Limit for LCL. The guidance acknowledges potential difficulties in generating samples precisely at the LCL and allows testing up to, but not above, a defined upper limit. For example:
- For products with a nominal concentration (N) ≤1%:
- LCL is defined as N minus 10% of N
- Upper limit for LCL is defined as LCL plus 2% of LCL
- For 1% < N ≤20%:
- LCL is defined as N minus 5% of N
- Upper limit for LCL is defined as LCL plus 1% of LCL
- For 20% < N ≤100%:
- LCL is defined as N minus 3% of N
- Upper limit for LCL is defined as LCL plus 0.6% of LCL
If testing exactly at the LCL is not feasible, sponsors may choose to test on batches that have passed their shelf life or have been stored under accelerated stability conditions. Each batch must be accompanied by a certificate of analysis confirming that testing was performed at the appropriate concentration.
- Representative Microorganisms for Efficacy Testing
The new guidance updates the selection of surrogate organisms used for validating label claims:
- Broad-Spectrum Virucide:
- Old Guidance: Permitted poliovirus type 1, human adenovirus type 5, bovine parvovirus, and canine parvovirus.
- New Guidance: Requires testing against any small non-enveloped virus from families such as Picornaviridae (e.g., rhinovirus), Parvoviridae (e.g., canine parvovirus), Caliciviridae (e.g., feline calicivirus), Astroviridae (e.g., human astrovirus), or Polyomaviridae (e.g., human polyomavirus). Poliovirus is no longer recommended due to WHO’s global polio eradication efforts, and adenovirus has been removed because it is classified as a large non-enveloped virus.
- For claiming against viruses, the efficacy test against Hardest-to-kill virus on the label should be performed at LCL, and all other virus disinfection claims can be tested at or below the nominal concentration. The new regulation defines the hardest-to-kill virus as any small, non-enveloped virus ( e.g FCV, CPV, or Rhinovirus) noted on the label. Otherwise, it’s a large-non-enveloped virus (e.g. adenovirus). If there are no large-non-enveloped viruses, it’s any of the tested enveloped viruses (e.g. Coronavirus, Influenza virus).
- General Fungicidal Claims:
- Testing against Trichophyton interdigitale (ATCC 9533) should be conducted at LCL, while other fungi (excluding Candida auris) may be tested at the nominal concentration.
- Mycobactericidal Claims:
- Testing against Mycobacterium bovis (ATCC 35743) or Mycobacterium terrae (ATCC 15755) should be performed at LCL.
- Sporicidal Claims:
- Tests for sporicidal claims must be carried out at LCL for Bacillus subtilis (ATCC 19659) and Clostridium sporogenes (ATCC 3584). For specific spores, tests should be performed at LCL.
- Food Contact Surface Sanitization:
- For non-halide biocides, testing against Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC 11229) should be performed at LCL; for halide biocides, testing against S. aureus or Salmonella enterica (ATCC 6539) should be at LCL. All other food contact surface sanitization claims can be tested at or below nominal concentration.
- Non-Food Contact Surface Sanitization:
- Testing against S. aureus (ATCC 6538) and one of either Klebsiella pneumoniae (ATCC 4352) or Klebsiella aerogenes (ATCC 13048) should be done at LCL. All other non-food contact surface sanitization claims can be tested at or below nominal concentration.
- Diluent (Hard Water)
The new regulation requests that all microorganism categories (bacteria, virus, fungi) should be tested at the same level of water hardness. It recommends using water with a minimum of 200 ppm hardness.
- Conclusion
The new efficacy guidance under Canada’s Biocides Regulations represents a significant evolution from the 2020 document. By establishing detailed parameters for GLP, specifying both lower and upper limits for certified concentrations, updating the list of representative microorganisms, and standardizing test conditions, Health Canada aims to ensure that biocides not only meet a minimum standard of performance but are rigorously validated under conditions that reflect real-world use.
Manufacturers should review these changes carefully, update their testing protocols accordingly, and ensure that all efficacy claims are fully substantiated by the required data. These steps are essential for a smooth transition to the new unified regulatory framework and for ensuring that Canadian consumers continue to have access to safe, effective biocidal products.
We will continue reviewing the new guideline in following weeks
Resources:
- Old Guidance (2020): H13-9-5-2020-eng.pdf
- New Efficacy Guidance (2025): Hard-Surface Disinfection/Sanitization Guidance