USP Microbiology Services | Frequently Asked Questions
When would I use USP methods for testing?
FDA 21 CFR Part 111 requires that test methods are scientifically valid and demonstration of their validity shall be recorded. USP is a valuable option that meets this criteria for many reasons. When a product is not a food item and falls into the category of a dietary supplement, probiotic, botanical, or drug product, then USP offers specific methods to allow for the complex nature of these product types. The complex active ingredients can often result in method interferences, false positives and negatives, and other issues. USP specific methods are appropriate for these types of complex matrices. Methods can be validated to show that the method is appropriate for the product being tested and would recover the organism of interest if it were present.
When should a suitability or preparatory test need to be performed?
For USP Microbiological test methods, suitability and preparatory analyses are performed to ensure not only the validity of the method for your product but also to decrease the chance of false negatives. Due to the complex nature of ingredients and compounds found in dietary supplement and probiotic products and ingredients, there are often matrix interference issues with common enumeration and pathogen detection methods. Performing USP suitability or preparatory testing is a way to ensure validity of the method for your products. The industry standard is to perform the suitability test on any product that is being tested for the first time. Periodic testing should also be performed as a quality control check when there are changes in the manufacturing of a product, including changes in suppliers or alterations to product formulations.
Why do we recommend suitability or preparatory testing?
Our priority is to help protect your brand by being diligent in today’s regulatory environment. You may find that some labs will conduct your tests without performing the required suitability testing and we are often asked why this is. This may be because it is expensive to keep stock of all supplies and organisms necessary to perform methods. In addition, performing suitability and preparatory tests may not be operationally possible for some. However, if you are looking to follow be “USP Compliant”, suitability and/or preparatory testing is required by FDA. Skipping this step can be risky as during an FDA audit you will want to make sure you have documentation supporting that the method is scientifically valid and appropriate for your product.
What is the difference between the suitability of test method and the preparatory method?
The difference lies in the type of product to be tested. The suitability of test method is specifically associated with the USP chapters 61 and 62, testing of non-sterile products, while the preparatory test is aligned with USP chapters 2021 and 2022 for testing of dietary supplements. The tests are very similar and generate information that identifies the possible presence of microbial growth inhibitors.
Does Eurofins track which samples have undergone suitability or preparatory testing?
Yes! We keep track of your product name each time a new sample is submitted. To make sure we do not repeat suitability on your sample, we suggest submitting the sample with the same product or reference a previous sample number to ensure our Registration Team can pull up your information. It is also best practice to keep track on your side which products or formulas have previously undergone suitability or preparatory testing. Working together will help eliminate the redundancy of unnecessarily performing once more on the same formula.
What information does Eurofins need when submitting a sample?
Due to the requirement to conduct suitability testing on the initial submission of each unique product formulation, Eurofins needs information regarding the products submitted for USP testing. This allows Eurofins to refer to the suitability testing that has already been completed for subsequent submissions of the same product and avoids adding unnecessary testing. This can be accomplished by one (or all) of the following routes:
► Include the full product name on each submission.
► Include the product SKU on each sample submission.
► Provide a reference sample number from a previous submission of the same product.
