The higher the bioburden on an object, the more difficult it will be to sterilize. Bioburden is normally defined as the number of bacteria living on a surface that has not been sterilized. The term is most often used in the context of bioburden testing, also known as microbial limit testing, which is performed on pharmaceutical products and medical products for quality control purposes.
Products or components used in the pharmaceutical or medical field require control of microbial levels during processing and handling. Bioburden or microbial limit testing on these products proves that these requirements have been met.