Answers are grounded in this paper and cite their sources.
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.
No takes yet. Share an insight, caveat, or question.
Bhadauria et al. (1980) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: