Waterless is safer from contamination, but not out of the woods

CosmeticsDesign asked testing laboratory company Eurofins​ what safety looks like in the world of waterless formulation. Below are Marco Piacentini, managing director and Martina Casini, lab manager at Eurofins Cosmetics & Personal Care Italy thoughts.

What does the landscape of safety in waterless formulations look like right now?​

Formulation with very low content of active water have been always considered to have less risk of microbial contamination. Yet, this is not completely true. Indeed, waterless products are not free from microbial contamination.

In facts, the absence of active free water in a formulation is only one of the endpoints to consider when assessing the risk of microbial contamination inside a formula, as it is clearly stated by appropriate ISO norms.

Furthermore, a waterless formulation maintain such a characteristic only when the product is sealed and closed, away  from air contact and human contact. As soon as the packaging is violated and bulk comes into contact with skin, free water is absorbed on the surface of the formulation and microbial contamination is possible. Particularly by molds and spores that are often totally underestimated when assessing the microbiological stability and in turn safety of a cosmetic product.

What kinds of challenges do waterless formulas face in regards to safety?​

While it is true that a waterless formulation offers a better chance to contrast a microbial contamination, still a good preservative system shall be always considered inside the formulation.

In facts, in these years, during which we have tested hundreds of thousands of cosmetics and personal care samples, we have clearly seen that waterless formulation are susceptible to bacteria, yeast and molds contamination.

This is a fact, supported by scientific evidences, that goes beyond all theories and hypothesis. Particularly, EU law 1223/2009 clearly indicates that all those cosmetics and personal care products that are addressed to critical uses, such as for children, people with fragile immune system, or that are meant to be used in contact with mucous membranes (mouth, eyes, genitals, …) shall be assessed with extra-care.

Therefore in the above mentioned cases the use of waterless formulas that are missing a solid preservative system shall be absolutely avoided.  

What types of waterless formulations face the most and least safety issues?​

We cannot name a specific formulation as all formulations are exposed to microbial contamination. For example powders, which are considered to be the least contaminable waterless products, may be contaminated with fungal spores.

Spores can resist high temperatures, humidity and other extreme environmental conditions. Also waterless product with an oily and fatty acids rich formulation can be a good substrate for specific microorganisms' growth.

The only formulation that can show a safe microbiological stability once the product is open are those with a properly assessed preservative system.

What else do brands looking into waterless need to know about safety for those formulas?​

Waterless formulations are good to minimize the risk of microbial contamination, but this aspect is not sufficient alone. A good preservative system shall always be considered inside the formulation.

Preservative system concentration, and composition can vary significantly with respect to the formula, the packaging, the foreseeable use and the target customer.