USP <2021> and USP <2022>

Microbial Content Testing:  USP <2021> and <2022>

USP <2021> and USP <2022> are tests primarily used to evaluate nutritional supplements of all kinds from raw materials to finished products.  USP <2021> involves quantitative testing for enumeration of total bacteria, yeast or mold present while USP <2022 > screens for the presence/absence of specified objectionable microorganisms.  CPT can also perform suitability and screening using USP <61> and <62>.

USP <2021> Microbiological Examination of Non-Sterile Products:  Microbial Enumeration Tests for Nutritional and Dietary Supplements

USP <2021> is a quantitative test (plate count) to enumerate bacteria and fungi that may be present in non-sterile Nutritional and Dietary supplements.  The tests performed are Total Aerobic Microbial Count (TAMC) and Total Yeast and Mold Count (TYMC).  Additionally, this chapter includes testing for Enterobacteria Count (Bile-Tolerant Gram-negative Bacteria) by the MPN method if required.

USP <2022> Microbiological Procedures for the Absence of Specified Microorganisms in Nutritional and Dietary Supplements

USP <2022> shows qualitative tests which determines the presence or absence of specified objectionable microorganisms or potential pathogenic microorganisms in non-sterile nutritional and dietary supplements.  The organisms that can be tested for in this chapter include the following:

  • Staphylococcus aureus
  • Escherichia coli
  • Salmonella species
  • Clostridia species


USP States that when objectionable microorganisms are not specified in the individual monograph, it is the manufacturers’ responsibility to determine which microorganisms in their products are objectionable.  It is not intended that all nonsterile nutritional and dietary articles be tested for the absence of all of the microorganisms mentioned in this chapter, nor is the testing of relevant microorganisms restricted to those presented in this chapter.

USP <2021> and <2022>Preparatory Test

Prior to performing MLT testing on any specific product or material-type, USP requires that method suitability or preparatory testing be conducted.  This is to ensure that the product/material does not inhibit recovery of organisms which may be present and could result in ‘false negative’ test results.  Any antimicrobial properties present in the product/material can be eliminated by dilution, filtration, neutralization or inactivation before testing that product or material.  This determines the valid dilution to be used for testing that product or material on a routine basis.

USP <2023> Microbiological Attributes of Non-sterile Nutritional and Dietary Supplements

This general information chapter offers recommendations for microbiological specifications for Botanicals Ingredients and Products, Nutritional Supplements and Products.  These microbial specifications should be provided to the testing laboratory when submitting samples for test method preparatory testing by these chapters.

Request a Quote for USP <2021> and <2022> Studies

Please Note: CPT℠ only performs testing for companies. We do not perform product testing for the general public.

Our facilities will be closed on Monday, May 30th in observance of Memorial Day.

Due to the forecast calling for snow and out of an abundance of caution we will be having a delayed opening tomorrow. Our facilities will now be opening at 10 AM on January 7th, 2022.