I take pretty decent care of my brushes. I wash them once a week, and I spray them with Sephora's anti-bacterial daily brush cleaner after each use. I decided that I wanted to see what effect brush cleaning had on the bacteria diversity living on my brushes.
For this investigation, I used my Tarte Airbrush Finish Bamboo Foundation Brush, which is my favorite everyday foundation brush.
|Now that I have posted the nail applique comparison, you guys can all see how long I have been procrastinating on certain posts...|
Using a q-tip, I exposed one Petri dish filled with an agar growth medium to the bacteria living on my unwashed brush. Then, I washed the brush and exposed a second plate to its cleaner state.
As a note, since this would be really easy for you to replicate at home: make sure that if you try this that you do NOT directly touch the brush to the agar. Otherwise, you would create a bacterial paradise on your brush!
Then, I waited for two weeks, ready to check out my fascinating colonies:
|The "before" petri dish.|
|The "after" petri dish.|
I will admit, at first I was a bit disappointed about a perceived lack of improvement between my "before" and "after" cultures. However, closer examination revealed that the difference was more noteworthy than it initially appears. That fuzzy mold obscures the truth! The "before" culture had what looks like about ten distinct species, whereas the "after" culture had a mere five.
Furthermore, it is worth noting that the fact that I consistently wash my brushes likely decreases the effect. Someone who hasn't washed their brushes in two months would likely see a much more dramatic decreased in bacterial diversity and species concentration.
So, what is living on my makeup brushes?
|I used a dissecting scope to help me characterize the colonies more accurately.|
The fuzzy white stuff is, as I already noted, clearly some sort of mold, although I am not certain what species it is. The yellow colonies look suspiciously like Micrococcus luteus, a Gram-positive bacteria that typically lives in dust, soil, and on human skin. There also seems to be a few colonies from the genera Bacillus and Colstridium, although, again, I am not certain about the species. Other likely culprits include Staphylococcus and Streptococcus.
Although all of these bacterial species would normally be present on your face in small quantities, the opportunistic bacteria that thrive on makeup brushes should not be continuously re-introduced to your face, lest they aggravate acne and other skin conditions. So, again: go wash your brushes. The internet will still be here when you get back.