Determination of Staphylococcus aureus in liquid eyeliners

Abstract

Introduction: Product quality and safety in the makeup industry are essential to protect the consumer health. The presence of pathogenic microorganisms, such as Staphylococcus aureus, in liquid eyeliners represents a risk to users' eye and skin health. Objective: To identify the presence of Staphylococcus aureus in eyeliners sold in the ¨El Arenal¨ shopping center in Cuenca. Methodology: An exploratory-descriptive research was conducted to quantify Staphylococcus aureus Colony Forming Units in liquid eyeliners. A convenience sampling was carried out, 30 cosmetics sales stands were chosen in the "El Arenal" shopping mall, selecting five stands for convenience. A total of 15 samples were chosen. The samples were prepared using Letheen enrichment broth with Tween. They were seeded in three selective culture mediums: Modified Letheen agar, salted mannitol, and Macconkey, and incubated at 37 °C for reading after 24 and 48 hours. They were identified by observing and recognizing colony morphology and confirmatory biochemical tests: catalase and coagulase. Results: The selected liquid eyeliner samples showed the presence of S. aureus in four out of the five stands tested. Biochemical tests confirmed the presence of S. aureus, with positive results in 40% of the total samples. Conclusion: The presence of S. aureus highlights the importance of cosmetic quality surveillance and control that the country's regulatory agencies must  carry out to protect public health and guarantee consumer safety.