Effective vs. Ineffective Preservation Using Water Activity*

By: David Steinberg, Steinberg & Associates

Posted: January 4, 2011

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It has been a belief of the cosmetic industry that the purpose of preservatives was to make a “clean” cosmetic under normal consumer use. In reality, the formulator is asking the preservative or preservative system to also prevent possible contaminations that may occur during production. A formulator never knows if the production of a clean cosmetic was achieved by strict adherence to cGMP’s or that the preservative system took care of any incidental contamination.

Although many people will disagree with these comments, even the FDA recognizes this thought. When a batch is produced and is contaminated, it is referred to as a “preservative failure.” Also, the FDA does not permit the post manufacturing treatment by external means, like radiation, heat sterilization, pressure, etc. to reduce contamination to acceptable levels.

Challenge tests of products to determine the adequacy of preservation usually challenge with “pure” cultures, and it is strongly recommend to include “house” isolates to be sure the preservative system is strong enough. How would a consumer possibly contaminate a cosmetic with “house” bugs? How would a consumer possible contaminate a product with a pure stain of bacteria? This illustrates the need need to concentrate on controlling and preventing microbial contamination during manufacturing.

HACCP is one of the best tools available to achieve this (see Seven Basic Principles of HACCP). It has been clearly shown that a well-designed and implemented HACCP studies reduce reliance on routine microbiological testing and provide a high degree of confidence in cosmetic product safety. HACCP's role is to determine points where microbial hazards exist. These points serve as CCP, which can be monitored and controlled. Critical limits can than be established for these points. 

More information on HACCP can be found through a few papers published by Preservatch and the International Life Sciences Institute.^3-5 In addition, training software is available for cosmetic company employees^a.