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Microbial Limits Testing

At Gibraltar Laboratories one of the most frequent questions we are asked about is what is the proper way to examine non-sterile products?  It is easy to test a sterile product because it is understood that the absence of pathogenic bacteria, yeasts and molds is expected. However, for non-sterile products it is understood that microorganisms are likely to be present. For ingredients or products specifically found in the USP/NF chapter 61 and 62 describe what needs to be done to perform and validate the test. Chapter 61 , Microbial Examination of Nonsterile Products: Microbial Enumerations tests describes how to determine how many organisms are present or the sample’s Bioburden. Chapter 62,  Microbial Examination of Nonsterile Products: Tests For Specified Organisms describes how to determine by microbial identification if specified organisms are present in the sample. Sometimes sponsors choose a similar test for the same purpose. If so, it cannot be called by the official USP name. In this case the test name may be Microbial Limits or Microbial Content. All of these tests share the common purpose of determining in a sample the number of organisms [colony forming units, CFU] present per gram. In many cases, regardless of the cfu/gram the sponsor applies a quality attribute to not accept certain organisms. The kinds of organisms that are not allowed are recognized to be pathogenic especially to the young, infirmed or otherwise immunocompromised patient. For example E.coli, Pseudomonas aeruginosa, Burkholderia , Staph aureus and Bacillus cereus are widely thought of as specified organisms to not allow to be present in the final product. However, there are many other organisms that are similar that may also pose a serious safety risk. For this reason, the sponsor must evaluate the kinds of organisms that are discovered during the enumeration testing. This is done by skilled microbiologists using sophisticated technologies such as the  Vitek biochemical identification and sometimes also by Genetic analysis. Gibraltar Laboratories is certified to help you with these important tests and performs them routinely with a  very fast turnaround time. In fact, our laboratory was the 2010-2011 winner of the ACIL Turn Around Time Award.