All you need to know about preservatives
- March 25, 2021
- Posted by: Nikole Tay
- Category: LS
The controversy of preservatives in products exists till today. As all of you know, inappropriate preservation may result in adverse effects to the health of consumers. Even so “preservatives-free” claims gained popularity. This term is misleading and can instil the idea that preservatives are unnecessary and harmful. However, this is not true. Preservation is mandated by the FDA stating that products sold to the general public must be free from contamination and safe for use when it is applied to the body.
In this article we will touch on importance of preservatives, determining preservation efficacy, preservatives market trends and regulations and preservatives used in cosmetics.
Why are preservatives important in cosmetics?
Cosmetics are breeding grounds for microorganisms. They are made around skin pH (4-6) which is optimal for bacteria and fungi to thrive. Water is a large constituent of these products and recent trends where natural plant extracts are preferred provides a prime environment with nutrients and vitamins that facilitate microbe growth.
How do we verify whether a product is sufficiently preserved?
These microorganisms are not visible to the naked eye and we cannot determine if a product is sufficiently preserved just by looking and smelling. Several tests have been recommended by different laboratories, but the challenge test remains the method adopted by the international regulations.
What is a Challenge Test?
A challenge test determines the stability and efficacy of a preservation system overtime. It is conducted during product development where a specific quantity of product is inoculated with known amounts of microorganisms such as bacteria and fungi.
The test runs over a period of 28 days and the mortality rate is measured in relation to the acceptance criteria set by official regulators.
It is recommended that the preservation efficacy is determined in these occasions
- When freshly prepared in the laboratory
- After storage in packaging container
- First production batch before packing
Which preservatives should I use?
With a general idea on how to ensure that your product is well-preserved, we will dive into some of the trends and common preservatives used in the cosmetics industry to help you select the right preservation system for your product.
Preservatives market trend
Over many years, global cosmetic manufacturers are looking for the best option to preserve their products while minimising the impact to consumers. Here are 4 major trends that dominates the preservatives market.
Common preservatives used in cosmetics
- Formaldehyde releasers
- Examples: DMDM hydantoin, imadozolidinyl urea, diazolidinyl urea
- This group of preservatives are effective against bacteria but weak against fungi.
- Examples: Methylparben, propylparaben, butylparaben
- They are an economical solution against gram-positive bacteria and fungi.
- Example: Methylisothiazolinone
- Isothiazolinones are broad spectrum preservatives, effective against bacteria and fungi.
- Click here to read more on How to tackle uprising issue of isothiazolinone-based preservatives?
- Organic acids
- Examples: Anisic acid, levulinic acid, sorbic acid, benzoic acid
- They function at pH 2 – 6 and are effective against most fungi.
- Glycol Ethers
- Examples: Caprylyl glycol, phenoxyethanol
- Glycol ethers are effective against some bacteria.
As seen above, most preservatives have their own strengths and weaknesses. A good rule of thumb is to use a blend of preservatives. There is no one size fits all and to provide broad spectrum activity against both bacteria and fungi, a product should include more than one type of preservative.