Bioburden is outlined as the range of bacteria living on a surface that has not been sterilized. This term is most often utilized within the context of bioburden testing. It’s also known as microbial limit testing, which is performed on pharmaceutical products and medical products to control and prevent microbial growth and contamination. Products or components utilized within the pharmaceutical or medical field should be assessed throughout the process to manage microbial levels. Bioburden is not the same for all products.

The bioburden of a product is influenced by the environment, product, and equipment. Bioburden or microbial limit testing on the product ensures that the products comply with the manufacturing quality standards.


Bioburden checks the percentage of microbes present on the medical device. Before performing the test, one has to take a look at the suitability and also plan as to what should be initially performed. The aim of the bioburden suitability test(also referred to as technique validation) is to confirm that the bioburden test technique is effective and helps to recover the microorganisms.

This test also helps to ensure that the testing can facilitate the expansion of the microorganisms on the surface of the device. The bioburden test determines the entire range of viable microorganisms in or on a medical device, container, or element. It’s performed on any product that needs management and monitoring of bioburden counts as a part of a sterilization program.

This test acts as an early warning system for potential production issues that might occur due to inadequate sterilization. It conjointly calculates the mandatory dose for effective radiation sterilization, and it observes product habitually as a part of quarterly dose audits.


Bioburden testing

  • Bioburden testing involves a typical assessment of associate degree aerobic microorganisms, and a suitable assay is performed.
  • Bioburden testing, or total viable count testing, indicates the microbial contamination levels of a product.
  • The raw materials used in the process of production are capable of introducing bioburden. The bioburden can also be introduced via the production setting process or through men who work.

Sterility testing

  • Sterility testing determines whether or not the equipment tested goes with the wants set forth within the individual treatise concerning sterility.
  • However, the procedures contained inside sterility tests won’t guarantee that the whole batch of the merchandise has been sterilized. Validation of the sterilization method, as well as sterile process procedures, is required to ensure that the conditions for the sterility area unit are met throughout the batch.
  • Sterility testing is going to be performed in a cleanroom under sterile conditions. The applicable validation tests performed on every sort of product assures that the product tested is clean, and the technique used can overcome any antimicrobial activity inherent within the product. Antimicrobial activity is neutral by any range of processes that embody membrane filtration, dilution, or chemical neutralizers like phospholipid or polysorbates. An antimicrobial is added additionally as well in the enrichment steps.


Automated detection of growth: Common growth is detected by incubating agar plates for 3-7 days, and also assessing microorganism growth by the naked eye, and the microorganism growth is detected. Many such approaches are on the market. For a machine-controlled traceable investigation of colonies, compact incubator plates are placed at a sensible location that takes high-resolution photos each half-hour, and specific algorithms are programmed to notice any growth that takes place. The results embody the expansion curve, along with the last image of the plate.

Staining: Filterable merchandise is processed like the compendial technique. However, once incubated (generally for a shorter time than samples evaluated by the human eye), they’re stained with CFDA (carboxyfluorescein diacetate), which is a non-fluorescent substrate. Inside the cell, the CFDA is cleaved to carboxyfluorescein which might be detected by the quantum system ahead of colonies and is detected by the human eye. As for the compendial technique, the limit of detection is one colony-forming unit (CFU), and identification of the isolate is feasible. This method has been validated.

Cytometry: Flow cytometry is used for bioburden, particularly once the acceptance criteria are high. For cytometry, the organism is fluorophore-labeled, so it is counted by the system. Flow cytometry and solid cytometry are each close to period detection. Flow cytometry is extremely convenient as its limit of detection is 100-1000 CFU. Solid section cytometry features a one CFU limit of detection. However, this technique is time-consuming, and identification isn’t possible.