USP <61> and <62>

Microbial Content Testing:  USP <61> and <62>

USP <61> and USP <62> are tests primarily used to evaluate raw materials, non-sterile pharmaceuticals, OTC finished products, personal care/cosmetic products and nutritional supplements.  USP <61> involves quantitative testing for enumeration of total bacteria, yeast or mold present while USP <62> screens for the presence/absence of specified objectionable microorganisms.  These methods are harmonized with the European Pharmacopoeia EP 2.6.12 and 2.6.13. CPT also performs suitability and screening for Burkolderia cepacia complex according to USP <60>.

USP <61> Microbiological Examination of Non-Sterile Products:  Microbial Enumeration Tests

USP <61> is a quantitative test (plate count) to enumerate bacteria and fungi that may be present in non-sterile products.  The tests performed are Total Aerobic Microbial Count (TAMC) and Total Yeast and Mold Count (TYMC).

USP <62> Microbiological Examination of Non-Sterile Products:  Tests for Specified Organisms

USP <62> shows qualitative tests which determines the presence or absence of specified objectionable microorganisms or potential pathogenic microorganisms in non-sterile products.  The organisms that can be tested for in this chapter include the following:

• Bile-tolerant Gram-negative bacteria
• Escherichia coli
• Salmonella species
• Pseudomonas aeruginosa
• Staphylococcus aureus
• Clostridia species
• Candida albicans

USP <61> and <62>Test Method Suitability

Prior to performing MLT testing on any specific product or material-type, USP requires that method suitability 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 <1111> Microbiological Examination of Non-Sterile Products:  Acceptance Criteria for Pharmaceutical Preparations and substances for Pharmaceutical Use

This general information chapter offers recommendations for microbiological specifications based on the nature of the product and its route of administration. This information should be provided to the testing laboratory when submitting samples for test method suitability by these chapters.