Preservative Efficacy Test

Anti-microbial Preservative Efficacy

An anti-microbial or preservation efficacy test detects the performance of preservatives added to cosmetic or personal care products. Preservatives are anti-microbial ingredients found in cosmetic formulations that maintain their quality by inhibiting microbial contamination.
We test all our formulations on five challenge microorganisms to check their anti-microbial or preservation efficacy effect.

What Are Challenge Test Micro-organsims & Why We Use Them?

The challenge microorganisms used in the anti-microbial or the preservation efficacy test include Candida albicans (yeast - a form of fungus), Aspergillus brasiliensis (filamentous mold - a form of fungus), Escherichia coli (bacterium), Pseudomonas aeruginosa (bacterium), and Staphylococcus aureus (bacterium). All these pathogenic micro-organisms represent a broad spectrum of manufacturing & household contaminants that a product can be exposed to, helping us to highlight the power of its preservatives.

How We Test The Preservation Efficacy Of Our Products?

Step 1

Introducing The Test Product

The first step involves separating the test product into five containers, each containing one challenge micro-organism. This includes Candida albicans,Aspergillus brasiliensis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus.

Step 2

Calculating The Initial Pathogenic Population Count

Next, the initial population count for all five micro-organisms in the test product is calculated by diluting the solution from the respective containers andculturing it on an agar plate (solidified gel base containing essential growth nutrients). The pathogens are then allowed to grow under appropriate lab conditions.

Step 3

Tracking The Growth Of Challenge Micro-organisms

Similar to the last step, the population count for each challenge micro-organism is calculated by the cell plating method at different intervals of time, i.e.,7 days, 14 days, and 28 days respectively. After each time duration, the concentration of the pathogen should reflect a steady decline as the preservatives work against them.

What's The Final Result?

For a product to show anti-microbial preservation efficacy, the bacterial microorganisms should reflect a 99% decline in their concentration by the 14th day and no increase by the 28th day. As for the fungal microorganisms, there should be no increase in concentration by the 14th & the 28th day. At Areoveda, tested products reflect similar results!