We offer various tests for bacteria, yeast, and mould detection starting at £45.  The basic tests can be used to help in developing effective preservation methods, and assessment of sterile working conditions to support GMP as well. Please email safety@oxford.bio for more details on this service.

Preservative Efficacy Testing – also known as Microbial Challenge Tests

Most products containing water will require a microbial challenge test under the new regulations.

Since these can take between 30 – 40 days it’s a good idea to get them completed as soon as possible.  The challenge tests generally cost around £150-£250, sometimes much more, and are offered by few companies in the UK.   Oxford Biosciences offers cosmetic product challenge testing for £150 per product.  The tests are commonly referred to as Microbial Challenge Test (Challenge) and Preservative Efficacy Test (PET) but they are the same test.

The challenge test examines the antimicrobial properties of the product.  If a significant decrease or no increase in viable count of micro-organisms is seen:

  • A 2 log reduction in the microorganisms counting after 14 days compared to that at the beginning
  • A 0.5 log reduction in the microorganisms counting after 28 days compared to that after 14 days.

If a challenge test has already been done on a very similar product, for example with a different perfume, it may not be necessary to repeat it.

A standard international test method must be used such as the EP (topical products) method or the new ISO method (11930:2012).

pH testing

If the pH of your product is below 3 or above 11 then this must be noted in your product’s information held on the CPNP.  It’s a good idea to record the pH of each product since a shift in pH can indicate a change within the product itself.

If you do not have a pH meter, we can do pH testing for you.  Oxford Biosciences offers pH testing for £8.50 per product.

Heavy metals

Oxford Biosciences can accurately test the levels of aluminium (Al), arsenic (As), cadmium (Cd), chromium (Cr), cobalt (Co), chlorine (Cl), copper (Cu), iron (Fe), lead (Pb), mercury (Hg), manganese (Mn), molybdenum (Mo), silver (Ag), tin (Sn), and zinc (Zn) in cosmetic products.

We charge £42 per metal per product.