The Relevance of USP Methodology in Microbiology for dietary supplements and cosmetic products – Part 2

By: Jennifer Johnson

Routine microbiological testing carried out by the Nutraceutical,
dietary supplements, cosmetics and toiletry manufacturing industries is determined by regulatory requirements. This applies not only to what should be tested and when, but also to the methods that should be used. Whether the final product is sterile or non-sterile, the bioburden exists from the raw materials, throughout the process and/or within the product’s environment (e.g. water) to the final product. A critical review of the overall microbiological process will determine whether the final product will meet its acceptance criteria. In addition, any “objectionable” or “specified” microorganisms that may be encountered during the procurement of raw materials and the processing must be considered.

Whether you are testing a raw material, an in-process sample, final product, or the environment, you should be aware of the critical role that microorganisms play throughout the process. You should also be familiar with the various microbiological related documents needed to determine whether the SOPs, validations, and regulatory body documents are being maintained to assure the control required to permit the final product to enter the marketplace as safe.

The Unites States Pharmacopeia (USP) is a non-governmental organization. Their documents are recognized as an official compendia book of methods and standards for Pharmaceutical, nutraceutical, dietary supplements, cosmetics, and toiletries. The USP offers a variety of documents such as monographs (published standards) and general chapters. General chapters with numbers 1000 are considered informational chapters.

Nutritional and Dietary Supplement USP Chapters
Since June 25, 2010, all dietary supplement manufacturers have been required to comply with the Food and Drug Administration’s (FDA) current good manufacturing practices (cGMP’s) according to the guidance outlined in USP chapters,, and.

<2021> Microbial Enumeration Tests – Nutritional and Dietary Supplements – This chapter provides tests for the estimation of the number of viable aerobic microorganisms present in nutritional supplements, from raw materials to the finished products.

<2022> Microbiological Procedures for Absence of Specified Microorganisms – Nutritional and Dietary Supplements -
Good manufacturing practices require that objectionable organisms be absent from non-sterile nutritional and dietary products. A microorganism can be considered objectionable if it represents a potential health hazard to the user who is using the product as directed, or if it is capable of growing in the product.

<2023> Microbiological Attributes of Nonsterile Nutritional and Dietary Supplements - The development of the formulation of nutritional or dietary supplements includes an evaluation of raw materials and their suppliers and the contribution made to the products by each ingredient and the manufacturing processes. Guidelines to help determine the appropriate tests to establish the microbial content of each ingredient are found in chapter.

The BioLumix system can perform all of the microbiological assays needed to get the finished product to the marketplace faster than traditional methods.

1. Microbial results can be generated in 24-48 hours in assays such as Total Aerobic Count, Yeast and Mold, Escherichia coli, Salmonella, Staphylococcus aureus, and Pseudomonas aeruginosa while utilizing one system.
2. The system can analyze tablets, capsules, powder, liquid and viscous material without any product interference.
3. The BioLumix system has software that is 21 CFR Part 111 compliant and BioLumix generates a customized validation book for each of its customers that include: Installation qualification (IQ), Operational qualification (OQ), and Performance qualification (PQ).

For more information click here.

Cosmetic and Toiletry USP Chapters
There are three USP chapters that are most important to the cosmetics and toiletry industries, <51>, <61> and <62>:

<51> Antimicrobial Effectiveness Testing - The ultimate purpose of the Preservative Efficacy Test (PET) is to determine the effectiveness of the preservative(s) present in a cosmetic or toiletry product. USP Chapter describes the type of products to be tested (categories), the specified microorganisms to be used for testing, and the inoculum and log reduction amounts required per category of product. The product to be tested is inoculated with a high number of bacteria, yeast, and mold, and the reduction in the initial inoculum amount is calculated over a 28 day period.

<61> Microbiological Examination of Nonsterile Products: Microbial Enumeration Tests - Suitability testing is performed in order to verify that the method utilized eliminates the effect of any antimicrobial properties of the product. Therefore, the media diluent combination does not inhibit the recovery and growth of microorganisms, if present in the sample. The goal of the suitability testing is to establish the ability of the test to detect microorganisms in the presence of product. The suitability described in USP verifies the validity of the testing method by showing the recovery of microorganisms in presence of the product.

Microbiological Examination of Nonsterile Products: Tests for Specified Microorganisms – Suitability testing using USP is performed by using selective media to detect various organisms such as: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, bile-tolerant gram-negative bacteria, Clostridia, Salmonella and Candida albicans in the presence of the product. The samples are first enriched by incubating in Trypticase Soy Broth (TSB) or another appropriate neutralizing media, and then streaked onto selective agars for the determination of presence of specified or the objectionable microorganisms.

The Relevance of USP Methodology in Microbiology in Pharmaceuticals

Fast, Reliable Preservative Efficacy Test and Microbial Detection for Cosmetics

Microbial contamination of cosmetic products is important to the industry and can be a cause of both product and economic losses. The water and nutrients present in the product can make them susceptible to microbial growth; although, only a few cases of human injury due to contaminated cosmetic products have been ever reported. More often, microorganisms are the cause of alterations in product appearance and smell; such as changes in viscosity and color or offensive odors.

The Challenge of Cosmetic microbiologists stretches beyond providing clean consumer products to be sold in stores, they need to provide safe products which will be reused following subsequent consumer self contamination.  Every time a brush, a sponge, a hand or other cosmetic applicator is wiped from one’s self and reintroduced to the product, microorganisms (which exist on everyone’s skin, eye lashes, lips, etc) are being transferred into the product. Cosmetic microbiologists need to develop product preservative formulations which are capable killing these newly introduced microorganisms before they multiply to harmful levels.  The demand to develop consumer friendly as well as environmentally friendly formulations that are less conspicuous to consumers and still protected against microbial contamination is greater then ever.  

To assure that the cosmetic products are going to be safe even after re-contamination by the user a “Preservative Efficacy Test” (PET) or “Challenge Test” is performed. The PET is performed by artificially and heavily contaminating a product with representative microorganisms. After defined periods of time, a specifically defined reduction in the microbial populations must take place.  The current plate count method requires numerous dilutions, sample plating, incubating, not to mention a great deal of plate handling and reading, along with tedious manual data transcription.

Resent trends in this field not only include research for fast, reliable alternative methods to detect microbial contamination, they include efforts to automate Preservative Efficacy Testing. To date there has not been an effective automated method developed for the Preservative Efficacy Test (PET).    

The BioLumix Alternative

BioLumix now offers an automated solution for both PET and microbial contamination on a single platform saving labor and consumables while reducing time to results.

The BioLumix Optical Technology is based on continuously monitoring changes of color / fluorescence as a result of the microbial metabolism in test vials. The results are presented as soon as detections occur without any involvement from an operator.  The technology utilizes a CO2 sensor that is a universal detector of aerobic bacteria, yeast and mold metabolism (Remember the Kreb’s cycle? Part of this metabolic pathway involves the conversion of carbohydrates, fats, and proteins into water, CO2 and energy).   

The procedure utilized allows for an easy estimate of the initial inoculum with a single ready-to-use vial that can replace multiple plates.  After the product interaction with inoculated product the system automatically calculates if the appropriate reduction in numbers of organisms was achieved.

The system is fully automated with automated data archiving, data maintenance in databases, and automated report generation.  It is paperless, increasing efficiency and saving on disposables, time and space, and best of all the system is unaffected by product interference.  Please call us for a free product trial.

Kevin LaBrecque