Testing the inhibitory effects of Mascara Life on bacterial growth in mascara.

Background: Mascara Life is a liquid additive that claims to reconstitute mascara consistency while retarding bacterial and fungal growth in tubes of used mascara. The purpose of this study was to compare the effectiveness of mascara alone versus mascara with the addition of Mascara Life against the growth of Staphylococcus aureus, a common bacterial contaminant responsible for potentially serious ocular infections.

Method: To simulate 3 to 6 months of use, 12 new tubes of Maybelline Great Lash mascara were dried for 5 consecutive days with the applicator wands removed. Mascara Life was added to a set of six tubes and an equal amount of saline was added to another set of six tubes. Equal amounts of eugonic broth were added to each tube to provide nutrients for the organisms and to further dilute the mascara. One tube from each set served as a negative control. The ten remaining tubes were inoculated with a standardized suspension of Staphylococcus aureus. Two calibrated samples from each tube were plated onto blood agar at 0, 1, 7, 14, 21, and 28 days after initial inoculation. The number of viable organisms was determined after 24 hours of incubation by the plate-count method.

Results: The concentration of viable bacteria was reduced to zero by day 7, and remained at this level through day 28 in all inoculated tubes. The negative control tubes showed no growth throughout the study.

Conclusion: The preservatives in both mascara and mascara with the addition of Mascara Life are effective in retarding growth of Staphylococcus aureus.