Microbiology of Dietary Supplements

Official Methods for Dietary Supplements

The USP methods for dietary supplements include:

USP <2750> Manufacturing Practices for Dietary Supplements: Contains the official FDA ruling on dietary supplement cGMPs (21 CFR Part 111).

USP <2021> Microbial Enumeration Tests-Nutritional and Dietary Supplements: Enumeration of the total number of aerobic bacteria, enumeration of the total number of combined yeast and molds, and the presence of bile-tolerant gram negative bacteria present in all nutritional supplements, from raw materials to the finished product.

USP <2022> Microbiological Procedures for Absence of Specified Microorganisms-Nutritional and Dietary Supplements: Procedure for determining the absence of specified objectionable organisms. Good manufacturing practices require that objectionable organisms be absent from non-sterile nutritional and dietary products. Objectionable organisms are defined as microorganisms that may cause potential health hazards to the user of the product and would adversely affect the product safety.

USP <2023> Microbiological Attributes of Non-sterile Nutritional and Dietary Supplements: contains information about frequency of microbiological sampling and testing, recommended microbial limits for botanical ingredients and products, and finally, recommended microbial limits for dietary supplement ingredients and products. However, specifications are typically are developed by the manufacturer with guidance from USP <2023>.

USP <1223> Validation of Alternative Microbiological Methods:  Any alternative method must be validated against these UPS methods using the methodology described in USP <1223> including side-by-side testing, determination of the accuracy, specificity, limit of detection, robustness, ruggedness, etc.

Many methods validated for food products, are not necessarily validated or appropriate for dietary supplements. For example, many methods have been written for very specific products such as eggs, meat, milk, nuts, etc. These methods were not written with dietary supplements in mind. And “dietary supplements” encompass such a large scope and variety of products therefore, it is risky to simply assume that a method written for example for eggs will also work for supplements.  Therefore, a method having AOAC certification is not necessarily appropriate for dietary supplements.  AOAC had not certified any microbiological method for dietary supplements, all their methods are certified for food only.

Often, one method will work for one product but not for a different product. Petrifilm methodologies are excellent methodology for many food products. However, Petrifilm should not be used on dietary supplement samples without thorough validation. For instance, samples that are dark in color and many common dietary ingredients might make it difficult to see growth on the Petrifilm. Viscous products such as Psyllium begins to harden before an appropriate spread on a Petrifilm can be obtained.

Product Interference or Matrix Effect

Spirulina, turmeric, Psyllium, honey, Calcium carbonate, dyes, and oils: these are just a few of the many products that the Nutraceutical industry works with, and struggles with. Many botanicals, herbals, enzymes or protein powders create challenges for microbiological testing (Tackling those challenging Nutraceutical Products with Rapid Automated Microbiology Testing!, C. Ockerman 2013). Granules (which can often be mistaken for a bacterial colony), extreme pH, viscous products can all interfere with the plate count methodology.

Microbial Testing of Dietary Supplement

Microbiological testing in the dietary supplement industry consists according to the USP chapters, of monitoring levels of naturally occurring indicator organisms and spoilage organisms, as well as the absence of objectionable organisms (e.g., Salmonella, Staphylococcus aureus, and E. coli) in finished products.

The typical battery of microbiological tests for a dietary supplement includes:

• Total Plate Count

• Yeast and Molds

• Enterobacteriaceae (gram negative bile tolerant bacteria)
• E. coli
• S. aureus

• Salmonella

• Pseudomonas (for liquid products or products with high water activity, or topical/cosmetic products)

How to Test for Microbiology

Many companies outsource the microbiology testing to third party commercial testing labs instead of performing it in house.  Some companies fell that whenever products are sent out for testing quality results cannot be questioned, but time is sacrificed and a premium price is paid for the service. Therefore, companies tend to only bring their microbiological testing in-house when they reach a critical mass such that the cost of sending out is equal to or more than starting up a laboratory.

In house Laboratories can perform using the USP methodology.  In preparing its own media and reagents the lab needs to pay attention to USP <1117> (Good Microbiological Laboratory Practices).  Because in an internal laboratory the quality of the results depends on the quality of the culture media prepared.  This includes accurate weighing of dehydrated components, the use of high quality (USP Purified) water, completely dissolving the dehydrated media or individual ingredients, and the need to control the heating of the media to avoid damaging heat-labile components of the media. The quality control of each batch of the media is a critical concern.

It is important to take production timelines into consideration when determining what methods fit each company individual needs.  A major issue with microbiological testing is the hidden costs in labor and inventory hold time.  The one assay that often keeps a quality control manager up at night is their yeast and mold testing—which takes five days to obtain a result.

Why Automated Rapid Microbiology?

Internalizing the microbiology testing and especially adopting rapid microbiological methods (RMM) can speed up the time to results from 7-10 days to 24-48 hours. The time saved has a direct and REAL impact on many key operational profit drivers.  The Advantages of RMM can include: Greater accuracy, better sensitivity, and increased sample throughput, automated data capturing and allowing easier data handling, and reduced cost for product release.  Rapid methods allow test results to be obtained faster. More importantly, if a product is above a desired microbiological specification, the results are obtained a lot sooner, and corrective action can be taken days before traditional methodology would allow.

All analytical methods need to be validated prior to their introduction into routine use, and this is especially true for novel technology platforms, such as rapid microbiological methods (RMMs). Because many RMM technologies consist of a combination of instrumentation, software, consumables and reagents, in addition to specific detection, quantitative or identification methodologies, it is important to develop a comprehensive and holistic approach to the validation process to ensure that the entire RMM system is suitable for its intended use.

The BioLumix Advantage
The BioLumix System is a system that fits a need in the Dietary supplement industry in terms of speed, working with all product matrices, and automatically documenting the results in real-time, thereby reducing the labor requirement for microbiological testing.

The BioLumix system was extensively validated for dietary products and compared to the methodology described in USP <2021> and <2022>.  The validation methodology followed USP <1223> “Validation of Alternative Microbiological Methods”.  This included performance criteria such as: side-by-side comparison to the USP methodology, accuracy and precision, specificity,  limits of detection and quantification, along with ruggedness and robustness, reproducibility of the results, false positivity rate and false negative rate.

A full validation package including Installation Qualification (IQ), Operational qualifications (OQ) and Performance qualification (PQ) is included with the BioLumix system
The BioLumix Advantages include:

  • The only system with all assays on a single platform
  • Real-time communication – early warning of contamination
  • 48-hour Automated Certificate of Analysis
  • Simplified testing with ready-to-use vials
  • Each vial comes with a certificate of analysis, negating the need for QC of the vials
  • Validated for dietary supplement products – IQ, OQ, PQ
  • No product interference
  • 21 CFR Part 11–compliant software
  • Remote-access customer support 24/7/365

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