All cosmetic and personal care products are expected by the FDA to withstand microbial attack within the use period of the product. However, not all cosmetic products are made the same or fall into the same categories. Therefore, standard preservative challenge test methods may not be suitable for all types of cosmetic products. For example, a standard USP <51> Challenge Test is defined for products with an aqueous base. Obvious problems can occur in products with a high water content, but seemingly harmless products made with talc or powder can become contaminated with harmful microorganisms as well.
Often time, products during the manufacturing process become contaminated with microorganisms that are not included in standard preservative challenge tests for cosmetics. In this case, it may be beneficial to challenge the products with those specific microorganisms to ensure the preservative system is able to inhibit the growth of them as well as those typically used in challenge testing. In addition to the microorganisms used in the standard preservative test methods, Cosmetic Test Labs has access to an extensive list of problematic microorganisms, including some that have previously been isolated from contaminated consumer products.