MICROBIOLOGICAL EVALUATION OF EXPIRED AND IMPROPERLY USED COSMETIC PRODUCTS: IMPLICATIONS FOR SKIN HEALTH

Abstract

Cosmetics are part of the daily routine of millions of people, used for personal care, hygiene, and aesthetics. Since ancient times, their use has been associated with the enhancement of appearance and well-being. However, improper use of these products, especially when expired or poorly sanitized, can pose risks to skin health by favoring the proliferation of pathogenic microorganisms. Considering the importance of the skin as a protective barrier and the growing concern about the microbiological safety of personal care products, this study aimed to evaluate microbiological contamination in expired and poorly sanitized cosmetic products, analyzing their possible implications for skin health. Samples of lipstick, mascara, tinted sunscreen, makeup sponge, and brush were selected in both new and used conditions. Microbiological analyses were conducted in the experimental laboratory of Centro Universitário IESB using BHI broth and blood agar culture media, followed by Gram staining and catalase tests. The results revealed microbial growth in sponge samples (new and used) and in the used brush, with identification of Staphylococcus aureus and Bacillus subtilis, microorganisms recognized for their pathogenic potential. In contrast, samples of lipstick, mascara, and tinted sunscreen showed no microbial growth, indicating possible effectiveness of preservatives in the formulation. It is concluded that prolonged and improper use of contaminated cosmetics can compromise the integrity of the skin barrier, causing dysbiosis, dermatitis, and other conditions. The study reinforces the importance of sanitizing makeup tools, properly discarding expired products, and the role of biomedical professionals in promoting aesthetic health.