Microbial Contamination in Makeup Products

Microbial Contamination

Presence of harmful bacteria in products.

Common Bacteria

E.coli, Staphylococcus aureus, Pseudomonas aeruginosa.

Bacterial Infections

Health issues caused by bacterial growth.

Preservatives

wear off over time and as a result bacteria can grow more easily

Nutrient Agar

Shows all bacteria

MacConkey Agar

focuses on harmful gram-negative bacteria

PBS Solution

Used to dilute samples

Dilution Factor

Ratio of sample to diluent in experiments. 1:1, 1:10, 1:100

Incubation Temperature

37°C for optimal bacterial growth.

Negative Control Plate

Plate with new, unused makeup for comparison.

Dilution vs no dilutions

Stepwise dilution to quantify bacterial concentration.

why does knowing the bacterial growth increase on used or expired makeup products compare to new, unused ones?

1. Helps people know when to

replace used makeup.

2. Shows which products

carry more health risks

3. Promotes safer hygiene habits

Step 1

labeling plates

Step 2

Sample collecting and dilution

Step 3

Serial dilution preparation

Step 4

Plating

More colonies grew on MacConkey Agar

without diltions

More colonies grew on

no dilution plates overall

Foundation, concealer, and. lipstick

grew the most colonies

The skin microbiome contains

more gram-positive/negative bacteria than those sustained on nutrient agar

Bacteria-containing makeup when discarded

can have environmental impacts