KOSMETIKVERORDNUNG, KONSERVATOR / 22-01-21
Preservatives in cosmetics
Often abused by beauty apps or media, preservatives remain key ingredients in cosmetics. Heavily regulated by the European regulation, they ensure the microbiological stability of cosmetic products, essential to meet the obligations of the safety of use. More knowledge about them helps us to understand their value.
Often abused by beauty apps or media, preservatives remain key ingredients in cosmetics. Heavily regulated by the European regulation, they ensure the microbiological stability of cosmetic products, essential to meet the obligations of the safety of use. More knowledge about them helps us to understand their value.
What is a cosmetic preservative?
Some consumers think that preservatives are dangerous, but they recognize they don't even know what a preservative is for in cosmetics. However, the European Regulation (CE) n°1223/2009 perfectly defines them: "substances which are exclusively or mainly intended to inhibit the development of micro-organisms in the cosmetic product ". A preservative can be added to a formula for this purpose, but it can also have another cosmetic function (like salicylic acid, which is both a preservative and an active).Preservatives under the European Cosmetic Regulation (i.e. with an effect on microorganisms, as bacteria, molds, and yeasts) should be distinguished from antioxidants like BHT or tocopherol, which only limit oxidation, not microorganisms. So, in this article, the term "preservative" will therefore refer exclusively to the former, substances listed in Annex V of the Cosmetic Regulations. This Annex establishes the list of preservatives allowed in cosmetic products. It's a positive list: it's not possible to use a preservative that does not appear in the Annex V. But why should the growth of microorganisms' in a cosmetic product be prevented?
Why using preservatives in cosmetics?
According to the Cosmetic Regulation, the safety of a cosmetic product includes the control of the microbiological risk. If compliance criteria are not detailed, the data about the microbiological quality control is required in part A of the Cosmetic Product Safety Report (CPSR) included in the Product Information File (PIF) (lien article PIF). The ISO 17516 norm establishes the microbiological limits to respect.| Category | Target | Microbiological limits* | Germs absent in 1 g or 1 ml of product |
|---|---|---|---|
| Category 1 | - Fragile population (children < 3 years old) -Fragile application area (mucous membranes, eye contour) | < 100 UFC / g ou UFC / ml | - Staphylococcus aureus - Pseudomonas aeruginosa - Escherichia coli - Candida albicans |
| Category 2 | - Other populations - Other application area | < 1000 UFC / g ou UFC / ml | - Staphylococcus aureus - Pseudomonas aeruginosa - Escherichia coli - Candida albicans |
* Counting of mesophilic aerobic microorganisms
Excluding some product categories or hostile formulas, cosmetic products are often very microorganisms friendly, because they contain water and ingredients that feed them. Microbial contamination can come from several origins, like the water, manufacturing process, packaging process, or raw materials. Natural raw materials, for example, are naturally loaded with microorganisms. The consumer is also a contaminant source during the use of the product, depending on the product category and especially its packaging.
The purpose of preservatives is precisely to have microorganisms, that are sometimes inevitable, from not developing in the product, before or during its use by the consumer. But they must be well chosen.
How to choose a preservative?
As previously specified, the first selection criterion for a preservative is its presence on the cosmetic preservatives list in Annex V of the Cosmetic Regulation! This Annex also specifies maximum concentrations, and sometimes restrictions of use. The choice of a preservative depends on several criteria, like:- Its spectrum of action: like antibiotics, each preservative exhibits its own spectrum of action. Some are more efficient on bacteria, others more on mold or yeasts, and vice versa
- Its solubility, that depends on the pH of the formula
- Its skin tolerance and toxicological profile: some preservatives can't be used on delicate areas, and some can't be used in some product categories (for example, sunscreen can't contain a photosensitive preservative)
- Its compatibility with the formula: some preservatives can't be used with specific ingredients. This could lead to the destabilization of the formula, or the ineffectiveness of the latter.
The origin of the preservative can also be a selection criterion. Preservatives can be from natural or synthetic origin. Some are naturally present in plants, like sorbic acid or benzyl alcohol. They can however be produced by synthesis. It's then a natural identical: they are the ones authorized in organic cosmetics (benzoïc acid, salicylic acid, sorbic acid, formic acid, benzyl alcohol, proprionic acid, dehydroacetic acid, and their salts).
What requirements for preservatives?
Choosing a preservative system for a cosmetic product is one thing, to ensure its efficiency is another. The responsible person must produce proof of the microbiological safety of the product, and thus of the preservative system. This proof is produced by performing the challenge test, as described in the ISO 11930 norm. A known concentration of microorganisms is inoculated in the product. A count of bacteria, mold, and yeast is then performed following a specific timeline over a month. To be considered valid, the challenge test must be performed following the ISO 11930 norm.Preservatives must feature in the ingredients list (lien article labeling), including those brought by raw materials and not intentionally added to the formula. That's why a formulation software, in which every raw material is specified and detailed, is a great tool to avoid forgetting a substance (and having to reprint the labeling!).
