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MPL Laboratories
12 Wilson Drive
Sparta, NJ 07871

Phone: 973-300-9715
A Full Service Microbiology Laboratory


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Preservative Efficacy Testing of Cosmetics

Category Press Release
Publish Date 8/31/2020
Author Paul Cochrane
Title Preservative Efficacy Testing of Cosmetics and Other Personal Care Products
Introduction MPL Laboratories provides microbial testing services for consumer goods in its FDA registered, cGMP and ISO 17025 compliant testing facility.
Sparta, NJ, August 31st, 2020

A research study published last year examined five categories of used cosmetic products to determine the potential risk to consumers due to microbial exposure. Over 450 lipstick, lip gloss, eyeliner, beauty blender and mascara products were tested for bacteria and fungi. The vast majority were found to be contaminated.

While this study looked at used cosmetics, it’s a good indication of what can grow on cosmetics over time during normal use. In this study, and others that have taken place over the years, microorganisms such as Escherichia coli (E. coli), Staphylococcus aureus (Staph) and other pathogenic bacteria have been identified. This is why preservative efficacy testing (PET), also referred to as antimicrobial effectiveness testing (AET), and expiry dates are so important to prevent potential microbial infections.

There are various approaches to PET/AET that have been developed over time by standards organizations, regulatory bodies, industries and companies. This includes U.S. Pharmacopeia <51> Antimicrobial Effectiveness Testing. In this test method, the preservative effectiveness of the product is examined by exposing the product to several types of pathogenic bacteria and fungi. Each organism is used separately and the product sample is examined over time to determine the effectiveness of the product’s preservative system.

MPL Laboratories is dedicated to supporting manufacturers, importers, distributors, retailers, regulatory agencies and the public with PET/AET and a wide range of other cosmetic and consumer good testing services. MPL Laboratories offers an accurate and reproducible determination of the degree of microbial contamination resistance for preserved personal care formulations. These tests are a critical element in the development of safe and effective cosmetics and other personal care products.

To learn more about cosmetic, personal care or other consumer product testing services provided by MPL Laboratories, please visit, call (800) 548-1874 or email

About MPL Laboratories

MPL Laboratories (formerly Marypaul Laboratories) was founded in 1985 as a full service microbiology laboratory. It is ISO/IEC 17025 accredited by PJLA, FDA and DEA registered, and NJDEP certified. MPL’s staff includes M.S. and B.S. degreed microbiologists and other dedicated scientists. The microbiology testing laboratory serves the pharmaceutical, cosmetic, personal care and food industries. MPL aims to provide its clients with high quality, reliable test data in a timely manner. The laboratory is part of the EMSL Analytical, Inc. network of laboratories across the United States and Canada.
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