Award Date


Degree Type


Degree Name

Master of Public Health (MPH)


Environmental and Occupational Health

First Committee Member

Patricia Cruz

Second Committee Member

Mark Buttner

Third Committee Member

Jennifer Pharr

Fourth Committee Member

Chad Cross

Fifth Committee Member

Karl Kingsley

Number of Pages



The complex nature of skin contributes to the microbial population present on its surface. While normal skin flora is either beneficial or has no effect on the body, there are instances where pathogenic microorganisms are present and can cause infections. Damaged skin is more susceptible to infections from these microbes. Behavioral characteristics, such as the use of cosmetics, can affect the microbial population present on the skin. Staphylococcus aureus is the organism most commonly isolated from cosmetics, and it can be responsible for conjunctivitis, impetigo, boils, and folliculitis.

There are many ways microbial contamination of cosmetics can occur, such as ineffective preservatives and consumer habits. With the advent of commercially-available cosmetic cleaning products, consumers may have a plausible means of reducing contamination on their cosmetics and cosmetic brushes. The objectives of this study were to determine the effectiveness of commercially-available cosmetic cleaners in reducing microbial contamination on cosmetics and cosmetic brushes. Cosmetics (i.e., eyeshadow/blush and lipstick) and large and small cosmetic brushes were inoculated with a known concentration of S. aureus, allowed a 0-, 1-, or 5-minute contact time, and treated with commercially-available cleaning products. Isopropyl alcohol and a cotton pad were compared to commercially-available sprays, wipes, and shampoos. Unused cosmetics and brushes were inoculated with the target organism, and culture analysis was used to determine the reduction of microbial concentration on cosmetics and cosmetic brushes after cleaning. On eyeshadows, the cotton pad exhibited a significantly greater reduction in microbial contamination compared to spray #2; 99.44% and 37.86%, respectively. For the lipsticks, both wipe #2 (99.77% reduction) and 70% isopropanol wipe (99.56%) had a significantly greater reduction in microbial concentration compared to the cotton pad (96.18%). For contact times, there were no statistically significant results. In addition, there were no statistically significant results for products used on the small brushes. On the large brushes, the wipes (98.01%) exhibited a greater percent reduction of microbial contamination compared to shampoos (89.92%).

The results of this study demonstrate that cleaning products, regardless of contact time with the microorganisms, cleaning product type, or cleaning product brand, were effective in reducing microbial contamination on cosmetics and cosmetic brushes. These results may provide valuable information to consumers about the importance of regular maintenance of their cosmetics and cosmetic brushes.


Cosmetic brushes; Cosmetics; In-store testers; Makeup; Microbial contamination; Shared use


Microbiology | Public Health

File Format


Degree Grantor

University of Nevada, Las Vegas




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