Preservative efficacy testing: considerations and areas for savings

By Joseph Heinzelmann

Often one of the first questions we receive about the BioLumix system is “how much does it cost?” While this blog post won’t be able to cover specifics on the costs of the BioLumix system or the individual tests, it will outline some of the considerations and areas for savings as it relates to preservative efficacy testing according to the United States Pharmacopeia <51>.  In our example analysis, we are able to reduce the cost of doing PET by nearly 40%.

USP <51> helps show the effectiveness of a preservative, or a preservative system. This testing is done according to the procedures outlined in USP Chapter <51> Antimicrobial Effectiveness Testing. This chapter describes in detail which organisms to use, the appropriate inoculum based on a product, and the necessary log reductions that the preservative system needs to achieve.

Before getting started on a comparison of protocols, we have to make sure a suitability study has been performed. The following link describes how suitability can be performed: The experts at Neogen can help you with your suitability testing questions.

Before a side-by-side comparison is done, a validation is required of any alternative method. Using the protocol outlines in USP chapter <1223> Validation of Alternative Microbiological Methods we can see that the BioLumix system meets the following requirements: Specificity, Limit of detection, precision and repeatability, robustness ruggedness, false negative rate, and false positive rate. A more in-depth discussion around USP validations and Neogen’s Validation book can be found here:

An overview of USP <51> can be found here: The two methods can be broken down into two approaches; materials and labor. Comparing the materials is straight forward. Reviewing the protocol shows that each time point requires an analysis of 3 bacteria, 1 yeast and 1 mold. Each organism requires a neutralization, and multiple dilutions when using traditional microbiology. Each organism also requires a total of 5 plates! Each plate requires a dilution blank, as well as a pipette tip.

There are several points of parity between the USP <51> traditional plate count methodology and the BioLumix system. First, the BioLumix system also requires 3 bacteria, 1 yeast, and 1 mold to comply with USP <51>. Each method will also test the preservative system at multiple time points over the course of 28 days. However, the BioLumix system is able to provide a microbiological count without 5 plates, without multiple dilution blanks, and without multiple pipette tips. The picture below helps illustrate how a nearly 40% reduction is achieved with Neogen’s BioLumix system methodology.

The second comparison is to determine the amount of labor required to run a USP <51> protocol with traditional methods. With the automation of the BioLumix system eliminates plate reading. The vials in the BioLumix system are automatically read, and the result is recorded in the database. Report writing is simplified with the Certificate of Analysis generated automatically. Time study estimates performed by Neogen estimate the labor reduction using BioLumix for PET is greater than 60%!

The BioLumix system is great for additional quality testing according to USP chapters 61 and 62. The advantages of BioLumix for this application has been covered in a recent blog post:

Learn more by asking our experts for a cost breakdown, suitability analysis or additional information by contacting the author or our microbiology experts.


Reducing the cost of preservative efficacy testing

By Joe Heinzelmann

The implementation of cGMP for all manufacturers (large and small) of dietary supplements andNutraceutical productsmeans that all manufacturers must test their products for microbiology quality assurance and generate a Certificate of Analysis for each batch. Products must be tested in accordance with the methods described in USP <2021> and <2022>.  This includes testing for Total Aerobic Microbial Count, Total Combined Yeast and Mold, Bile-Tolerant-Gram-Negative bacteria, and objectionable organisms (absent in 10 grams of organisms such as SalmonellaE. coli, and sometimes S. aureus). To do these tests companies either send product samples to contract laboratories for microbiological testing or test them internally.

Internal testing of products for microbiology gives the manufacturer much more control over the operation, but some manufacturers are hesitant to bring the microbiology testing in-house for fear of the complexity of testing or the need for trained microbiologist(s).  Also daunting is the need for a full validation package which is required for any method that deviates from the USP methodology. Here’s the good news – BioLumix offers a solution that gives faster time to results, quicker product release, cost effective operation, and strengthens key profit drivers.   This is all achieved on a single platform that is easy to use, validated to USP requirements, and doesn’t require additional skilled personnel.

At BioLumix, we don’t just offer you a simplified, rapid, automated microbiology system… we provide the Complete BioLumix Experience!

What is the Complete BioLumix Experience?  It’s having, from initial contact to the completion of the installation and beyond, our commitment to providing unparalleled support and total customer satisfaction.

In 2006, Ruth & Gideon Eden established BioLumix, Inc.  Today, because of their extensive backgrounds in science and technology combined with customer-oriented sales and support staff, we have raised the simplification, automation and speed of microbiology testing to a new level.

  • Needs Assessment - Whether you contact us direct or through our website you can count on our sales team to respond quickly.  The focus is on your needs and goals.  Our BioLumix Technology Presentation provides an in depth look into how and why our system will work for you.  In addition, we can quickly and easily show you the value and the ROI the system will bring to your company.
  • Expertise – Knowing how the BioLumix system will work with your samples gives you peace of mind.  That’s why we test samples – YOUR samples – for you at our laboratory in Ann Arbor, MI.  We do this for you at no cost and at no obligation!  Once completed, expect a comprehensive report from one of our expert microbiologists. That same microbiologist spends two and a half days on-site for training and installation of the system.
  • Validation – If you are concerned about validation, here is more good news.  We provide complete SOPs along with a customized Validation book which includes Installation Qualification (IQ), Operations Qualification (OQ) and Performance Qualification (PQ).
  • Simplicity and Ease-of-Use-  The easy to master BioLumix system offers a new level of productivity.  Sample preparation takes less than 2 minutes; just add the sample to the diluent and mix.  Pipette the appropriate amount into the vial and place it into the instrument and record the sample and assay information into the computer.  The rest is totally automated.  The Certificates of Analysis will automatically be generated in as little as 24-48 hours!
  • Support – Our jobs center on satisfying our customers and providing unparalleled support.  At BioLumix you receive 24/7 support plus a microbiologist dedicated to service you and answer your questions.  What happens if you encounter a problem? Troubleshooting can be done via the internet and in most cases problems are resolved.   If needed we provide a loaner instrument while your instrument is being fixed to minimize downtime.  Our website provides instant access to information and resources about our technology, instruments, assays, and more.  It’s also mobile-enabled to format to your handheld devices.  Links to social media, white papers, blogs, videos, and other informative contact information puts everything you need at your fingertips.
  • Continuous Product Improvement – At BioLumix we have an ongoing commitment to evolving and adding to our platform.   One way this is achieved is through our partnership with our customers.  Customer feedback, along with a desire to increase the breadth and depth of our offerings, helps us to make improvements to our media and our assays.  We have recently introduced two new assays – Listeria and Bacillus cereus.

With a simplified method such as the BioLumix System we can provide a simple cost effective method to test products for microbiology.

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