Methylisothiazolinone (MI or MIT), a preservative used in cosmetics and other household products, recently has been in the news. Of course, preservatives are essential in almost all cosmetics to prevent the growth of microorganisms during product use, and sometimes to extend the shelf-life of a product, which of course is in the consumer’s interest. Who would want to buy a product that did not last long enough to use it all?
Discarding unused but unusable products is hardly sustainable, but preservatives are much more important for other reasons. Contaminated products can become unpleasant due to off-odors, unpleasant textures and unsightliness. They may also lose efficacy, since the performance of a product often relies on its integrity. In addition, contaminated products can be unsafe to use, potentially introducing large numbers of pathogenic organisms onto the skin, mouth or near the eyes. It is therefore in the consumer’s interest for product manufacturers to ensure the microbiological stability of cosmetics—and this, in most cases, is through the use of preservatives.
European Cosmetics Regulation No. 1223/2009 defines a preservative as a substance that is exclusively or mainly intended to inhibit the development of microorganisms in the cosmetic product. It also stipulates that cosmetic products on the EU market may only contain the approved preservatives listed in Annex V. To be listed in this annex, safety data must be submitted to the European Commission (EC) to be evaluated by its Scientific Committee for Consumer Safety (SCCS). If the dossier gains a positive opinion from the SCCS, a proposal to amend legislation is drafted by the EC and must then be approved by the Member States before being published in the Official Journal of the European Union as new legislation.