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Loss of effectiveness of preservative systems of mascaras with age
Abstract:
The preservative systems of unused, anhydrous mascaras were challenged periodically with microorganisms, using a modified membrane procedure. Shelf life of preservative activity against Pseudomonas aeruginosa varied for different brands from as little as 1 month to over 36 months. Generally, P. aeruginosa grew in mascaras after the mascaras were challenged first with Staphylococcus epidermidis or Candida albicans.
Insights
Preservative effectiveness in anhydrous mascaras varied greatly, with some brands offering over 36 months of protection against Pseudomonas aeruginosa. Microbial challenges showed P. aeruginosa often grew after initial exposure to Staphylococcus epidermidis or Candida albicans.
Area of Science:
- Microbiology
- Cosmetic Science
- Pharmaceutical Science
Background:
- Preservative systems are crucial for maintaining the microbial quality of cosmetic products.
- Anhydrous formulations, like mascara, may still be susceptible to microbial contamination and degradation.
- Understanding the efficacy of preservatives against common contaminants is vital for product safety.
Purpose of the Study:
- To evaluate the preservative efficacy of unused, anhydrous mascara formulations.
- To determine the shelf life of preservative activity against specific microorganisms.
- To investigate the impact of sequential microbial challenges on preservative effectiveness.
Main Methods:
- Modified membrane procedure used for microbial challenge testing.
- Periodic testing of preservative systems in anhydrous mascaras.
- Assessment of growth of Pseudomonas aeruginosa, Staphylococcus epidermidis, and Candida albicans.
Main Results:
- Significant variation in shelf life of preservative activity against Pseudomonas aeruginosa was observed across different brands (1 month to over 36 months).
- Pseudomonas aeruginosa demonstrated growth in mascaras subsequent to initial challenges with Staphylococcus epidermidis or Candida albicans.
- The study highlights variability in the robustness of preservative systems in anhydrous mascara products.
Conclusions:
- Preservative efficacy in anhydrous mascaras is highly brand-dependent.
- Sequential microbial exposure can compromise the preservative system's integrity.
- Further research is needed to optimize preservative strategies for long-wear cosmetic formulations.