Peptide Microbiology Testing: Sterility, Bioburden and Endotoxin Explained

Abstract & Executive Summary

Chemical tests such as HPLC and mass spectrometry confirm what a peptide is and how pure it is. They cannot detect bacteria, fungi or bacterial fragments. That is the job of microbiology testing.

This guide covers the four microbiology checks most often referenced in pharmacopeial standards and on quality documents.

Microbiology test map

  Bioburden            ->  How many microbes?
  Specified organisms  ->  Are particular species present?
  Sterility            ->  Any living microbes at all?
  Endotoxin            ->  Any bacterial fragments?

1. Bioburden (Microbial Enumeration)

Bioburden testing counts the number of viable microorganisms in a sample. Results are reported as colony forming units (CFU) per gram or per millilitre.

2. Tests for Specified Microorganisms

This test looks for particular organisms, such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella species.

3. Sterility Testing

Sterility testing checks for any viable bacteria or fungi at all. Samples are incubated in growth media, usually for 14 days.