USP and Contamination Recovery Rates

United States Pharmacopeia (USP) "Microbio­ logical Control and Monitoring of Aseptic Processing Environments" approaches analysis of environmen­ tal monitoring (EM) data in the aseptic core from a perspective of "contamination recovery rates" while noting a need to improve EM data analysis. There are two difficulties in using EM data from the aseptic core: • Most of the plate counts should be "zero" • The actual numerical plate counts seen are far below the limit of quantification (LOQ) for the plate count method.