Microbial Examination of Nonsterile Products: Microbial Enumeration Tests USP <61> Q. Can I use strains other than those that are cited in the USP? A. You should use the strains that are cited in this chapter or equivalent strains from other culture collections. For example, if Pseudomonas aeruginosa ATCC 9027 is indicated, you should use this strain or strains … [Read more...]