Bacteria thrive in bathrooms

Cosmetic products, especially those used on sensitive areas, can become breeding grounds for bacteria if not used or stored properly, according to Christophe Mercier-Thellier. Bathrooms are often warm, humid, and confined, creating ideal conditions for microbial growth, particularly because many creams and lotions contain water and nutrients.

Fingers spread bacteria

Even clean fingers carry millions of bacteria, which can contaminate products when they are submerged directly into jars. While cosmetics contain preservatives to prevent bacterial growth, these preservatives are tested at 20°C, not the typical 30°C of a bathroom, which can reduce their effectiveness and allow more bacteria to develop.

Hygiene tips for cosmetics

To maintain cosmetic hygiene, it is recommended to use a clean small spoon that is washed with water and soap after each use or prefer tubes or pump bottles. When using a tube, avoid touching the tip directly and let the product fall without contact.

Sharing cosmetics is risky

Sensitive products such as mascara, kohl, lipstick, and roll-on deodorants should never be shared, as they can transfer bacteria and increase the risk of infections such as conjunctivitis or keratitis.

Understanding product labels

Cosmetic products have a shelf life indicated by two labels: the DDM (Date of Minimum Durability) and the PAO (Period After Opening). DDM is mandatory if the product expires within 30 months after production and is symbolized by an hourglass or the phrase "To be used before end...".

Label meanings and safety

PAO is indicated by an open jar pictogram with a number and the letter "M", such as "6M" or "12M", meaning the product remains effective and safe for 6 or 12 months after opening. Products with labels such as Cosmébio®, Natrue, or Nature & Progrès typically contain fewer preservatives, which may result in shorter DDM or PAO periods.

Proper storage and disposal

A permanent marker can be used to note the opening date on the product jar, and any changes in smell, color, or texture should prompt immediate disposal of the product. Exceeding these limits can lead to the depletion of preservatives, rancidity of fatty substances, collapse of active ingredients, and proliferation of microbes.