Preserving the Impossible: challenging natural-based formulations

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Facial masks applications are considered a preservative challenge, especially cleansing masks with natural ingredients such mud and clay. Masks are left on the facial sensitive areas for 20 minutes, by consumers of all ages. Therefore, irritation is a major concern. Mud and clay are preferred by consumers and are considered as safe. However, just because an ingredient is originating from nature, it doesn’t mean it’s safe for use. For mud and clay, it is even more critical, as these ingredients can carry everything that is originating in the ground, including microorganisms.

Often, the formulator would not know where is the origin of the mud, how is it processed or treated.  A typical bacteria count in mud could be 10⁵ – 10^7. today, a costly radiation process is the standard to treat mud, as very few acceptable preservatives can meet the challenge to eliminate the microbial risk. Even when the material is sterile, as it is introduced into the formula, the interaction with water could generate a preservation issue. Combining the original state of the raw materials and its interaction in the formula is raising a need for a high efficacy solution.

Based on research done by Sharon Laboratories on face masks applications, we show that working with Sharomix™ Amplify preservative systems, will provide broad spectrum protection for both the mud itself as well as the face mask. This patent-pending line offers high efficacy system, allowing a significantly reduced level of use, generating the benefits of higher compatibility in the both anionic and cationic formulations, reduced risk of irritation and regulatory compliance.

Sharomix™ AM25 used on untreated, non radiated mud from the Dead-Sea area, and at a level of use of 1%, generated TMAC results of <10, therefore allowing either avoiding the costly radiation process, or changing from an existing harsh preservative to a consumer oriented option.

The next step was testing the efficacy in a formula containing 20% Dead-Sea mud. Challenge test was performed on non-radiated mud, with the preservative Sharomix™ AM25 at a level of 1%. Additional challenge was done to a formula with 20% treated mud, with Sharomix™ AM25 at a level of 0.7%. both tests passed with great results: after 48 hours all 5 microorganism had a significant log reduction to <10 , showing the flexibility of the system to handle both high risk material, as well as treated one at a low usage.

The same study was performed on Bentonite and Kaolin face mask, with similar good results, with Sharomix™ AM20. To answer the call for phexnoyethanol-free preservation in facial products, a similar study was executed with Sharomix™ AM24. This system, used on the same tough-to-preserve formula containing 20% mud, successfully preserved the product at a level of 0.8%.

In conclusion, a naturally derived ingredient does not guarantee safety. In the world of preservation, it is often the opposite. When formulating facial care products with such ingredients we must take all this into account and search for the right solution to answer all aspects: efficacy, formula compatibility, product claims, regulation and of course, safety.

Written by Naama Eylon, VP Personal Care

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