Preservative Efficacy Testing (PET) For Cosmetics & Personal Care
A preservative efficacy test (PET), also known as a challenge test or antimicrobial effectiveness test, is a crucial evaluation process conducted to assess the ability of preservatives to inhibit microbial growth and maintain product stability in various consumer products, including cosmetics, pharmaceuticals, and personal care items.
Preservative Efficacy Testing for Cosmetics & Personal Care Products
Cosmetic and personal care products are ‘challenged’ when a known level of microorganisms are added to the product. The product is tested over 28 days, and the efficacy of the preservative system is determined using the rate of microbial reduction. The organisms used are ones which are known to pose risks of spoilage or microbial contamination. Preservatives play an important role in preventing microbial proliferation, hence ensuring the safety, efficacy, and shelf-life stability of the cosmetic product.
Our methods
Our Preservative Efficacy Testing procedure adheres to industry standards and guidelines, including EP 5.1.3 and BS ISO 11930. Here's a brief overview of our method:
-
Sample Preparation
A specified amount of the cosmetic product is decanted into individual aliquots, each inoculated and homogenised with a known level of 5 microorganisms; E. coli, P. aeruginosa, S. aureus, A. brasiliensis, and C. albicans. This step ensures consistent and controlled inoculation across all samples.
-
Incubation
The inoculated samples are then incubated at a predetermined temperature (22.5±2.5°C) for a specified duration, following established testing schedules. Throughout incubation, we test the samples to assess microbial growth and evaluate the efficacy of the preservative system in inhibiting microbial proliferation.
-
Confirmation Tests
We perform confirmation tests on any resulting microbial growth to determine the level of each inoculated organism present in the samples. This step allows us to quantitatively assess the performance of the preservative system and identify any deviations from regulatory requirements.
-
Data Analysis
The data is analysed to calculate the Log reduction, which represents the reduction in microbial load from the beginning to the end of the testing schedule. This quantitative analysis provides valuable insights into the efficacy of the preservative system in maintaining product integrity and safety.
Why is Preservative Efficacy Testing Needed?
Preservative Efficacy Testing plays a critical role in ensuring the safety, efficacy, and stability of cosmetic products. By assessing the ability of preservatives to control microbial contamination, this testing regimen helps mitigate potential health risks associated with microbial proliferation in cosmetics. Moreover, it provides cosmetics and personal care companies with essential data to optimise preservative formulations and enhance product quality.
At SMS, we take pride in offering UKAS-accredited Cosmetic Challenge Tests (or PET), along with GMP Preservative Efficacy Testing at our sister laboratory, Tentamus Pharma UK, in Derby, should you require GMP testing for your cosmetic products.
Feel free to contact us using our contact form.