Introduction to Biocides Testing

At Melbec, we can offer one of the most comprehensive lists of biocidal tests available within a UK laboratory. In addition to our UKAS accreditation to ISO/IEC 17025:2017, we are also accredited to perform two of the most popular biocidal tests – EN 1276 and EN 13697.

Flexible scope UKAS accreditation

In addition to our fixed scope UKAS accreditation, we are also accredited to perform other Phase 2, Step 1 tests under UKAS accredited methods following a flexible scope procedure. This means that Melbec hold flexible scope accreditation for assessment of disinfectants, antiseptics, and biocides using phase 2 step 1 quantitative suspension test methods, with the purpose of a flexible scope accreditation to allow organisations to add activities to their scopes in which they have already been assessed in similar activities. These additions can therefore be made without the need to wait for an assessment from the accreditation body (UKAS). These additions will not be explicitly stated on our schedule of accreditation.

Biocidal Products

What are biocidal products?

Biocides are a chemical substance designed to destroy any harmful organisms. A biocidal product is a product containing one or more biocidal active substances, often alongside co-formulants. An active substance is a chemical compound, or a microorganism itself, used within a biocidal product that is responsible for making the product effective. A co-formulant is a substance that is not considered biocidal, but may help a product be more effective, such as stabilisers, preservatives, colourants, or fragrances.

Examples of biocidal products include:

  • Disinfectants
  • Preservatives
  • Pest control
  • Antiseptics
  • Hand sanitisers
  • Wipes
  • Anti-bacterial handwashes and hand rubs
  • Insecticides

Biocidal products are strictly regulated. Within the UK, products are regulated by the Health & Safety Executive (HSE), under the Great British Biocidal Product Regulation (GB BPR). In the European Union (EU), they are governed by the Biocidal Products Regulation (EC) No. 528/2012 (EU BPR), via the European Chemicals Agency (ECHA).

To market a product, it must comply with the regulation; including the use of active substances and list of suppliers approved by the relevant BPR.

Since Brexit, the person responsible for the biocidal product (authorisation holder) or the supplier must be established in the UK for a product to legally be sold within the GB markets.

Product labels

Any product sold must contain sufficient information so that it can be used effectively and safely. This information is usually relayed primarily through the product label.

Biocidal products that wish to make a label claim must be supported by relevant efficacy test data.

How to make a biocidal claim

Tests are categorised into 3 phases:

Phase 1: Mostly used in the development stages of products, either to prove an active substance within a product could be biocidal (for BPR submission to the list of approved active substances), or to prove that a co-formulant within a product has no biocidal activity – e.g., some essential oils have antimicrobial products, so if these are used to fragrance a product, they may wish to be screened to ensure that they are not contributing to reducing the number of organisms. In addition, sometimes several co-formulants mixed may react with one another to produce additional compounds that could also do the same thing.

EN 1040
Basic bactericidal activity of chemical disinfectants or antiseptics
EN 1275
Basic fungicidal / yeasticidal activity of chemical disinfectants or antiseptics
EN 14347
Basic sporicidal activity of chemical disinfectants or antiseptics

For these tests, NO interfering substance is used, and instead, water is used.

A standard contact time of 5 minutes (bacteria), 15 minutes (fungi/yeasts) and 30, 60 or 120 minutes (bacterial spores) is used for testing. For bacterial spores, results are compared to reference test solutions.

As Phase 1 testing does NOT take into consideration specific applications, therefore CANNOT be used to make a biocidal claim.

Phase 2: Phase 2 testing is broken down into 2 steps:

 Step 1 (2/1) refers to quantitative suspension tests to establish that a product has biocidal activity (e.g., bactericidal, fungicidal, sporicidal, virucidal etc.) within a liquid suspension under simulated practical conditions appropriate for use.

EN 1276
Bactericidal / Food, industrial, domestic, and institutional area
EN 1650
Fungicidal / Food, industrial, domestic, and institutional area
EN 13727
Bactericidal / Medical area

Step 2 (2/2) refers to quantitative laboratory tests to establish biocidal activity (e.g., bactericidal, fungicidal, sporicidal, virucidal etc.) when applied to a surface or skin under simulated practical conditions.

EN 13697
Bactericidal & Fungicidal / Medical & Food, industrial, domestic, and institutional area
EN 16615
Bactericidal & Yeasticidal / Medical - Wipes
EN 17387
Bactericidal & Fungicidal / Medical (New 2021)

Phase 2, step 1, and phase 2, step 2 tests are generally needed in combination to support efficacy claims for chemical disinfectants or antiseptics. This is because dried-out (desiccated) microorganisms may be stressed and therefore offer different challenges to biocides, in comparison to those within a liquid suspension.

 

Phase 3: Phase 3 testing includes tests under actual conditions, rather than laboratory conditions (field tests or on-site tests). Guidelines are in place for the scope of the testing requirements; however no current standards are in use for phase 3 testing, but they may be developed in the future. For phase 3 testing, bespoke methods related to specific applications can be created by Melbec to aid product efficacy claims.

All biocidal testing can be carried out using standard organisms or can be adapted to include alternative organisms required to support individual product claims. If these standards are not appropriate to support a product claim, we have the technical knowledge and expertise to develop and validate a bespoke method relevant to your requirements.

To discover our full range of testing, please use the questionnaire tool below to discover which standard tests you may require to complete your biocidal product claim:

[Insert “How to make a biocidal claim” information / infographic questionnaire here]

Disinfectants – Modes of Action

There are many different types of disinfectants used within biocidal products, including:

  • Alcohols
  • Chlorine and chlorine compounds
  • Hydrogen Peroxide
  • Quaternary Ammonium Compounds (QACs)

 

Alcohols:

The mode of action for alcohols is by denaturation of proteins. Alcohols are commonly found in products including hand sanitisers, wipes, and disinfection liquids. Alcohols are generally a good biocidal choice for bacteria, fungi, and viruses. Generally, they are slightly more effective against Gram-negative bacteria than Gram-positive. Alcohols are ineffective against bacterial spores, and for fungi, alcohols are sometimes inconsistent, and higher concentrations are generally required compared to bacteria.

Did you know, 100% ethanol is less bactericidal than 70% (when the alcohol is diluted using water). This is because the ethanol takes longer to evaporate, and this longer contact time means that it can penetrate cells more effectively.

 

Chlorine and chlorine compounds:

For these types of disinfectants, the exact mode of action is unclear, however several modes of action, including oxidation of enzymes and amino acids and DNA breakdown are associated with chlorine compounds. Hypochlorites are the most widely used of the chlorine disinfectants, usually as liquid (Sodium hypochlorite). Household bleach is a common example of a disinfectant containing chlorine. It is a broad-spectrum disinfectant against bacteria, fungi and viruses. Often at concentrations considered biocidal, hypochlorites are often corrosive and can cause skin irritation and burns, therefore care should be taken with use.

Hydrogen Peroxide:

Hydrogen Peroxide works by producing hydroxy free radicals that attack membrane lipids, DNA, and other vital cell components. They show good germicidal activity for bacteria, fungi, spores, and viruses.

Most frequent concentrations used generally range from 6-25% within products.

Hydrogen peroxide is very stable when stored but can cause chemical irritation when used and can also cause cosmetic changes on surfaces, so care must be taken.

Quaternary Ammonium Compounds (QAC):

This type of disinfectant is widely used, with bactericidal action from inactivation of energy-producing enzymes and cell membrane disruption. Generally, it shows good fungicidal, bactericidal and virucidal activity against enveloped viruses. However, QAC’s are not sporicidal, and generally not tuberculocidal or virucidal against non-enveloped viruses. QAC’s are often used in general hygiene products.

 

 

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