3 Methods of Sterilization to Increase Sterility Assurance Level

sterility assurance level
Sterile hospital instruments must undergo sterilization and SAL

Sterility assurance level (SAL) refers to the probability of a microorganism surviving the sterilization process, making the item non-sterile. Currently, a SAL of 10–6 is considered acceptable. Read more about the sterility assurance level HERE.

To achieve sterility a device must go through the sterilization process, have sterilized components, sterile filtration, and be contained in a sterilized container, and go through chemical or physical sterilization and aseptic processing. Many sterilization methods exist including autoclave steam sterilization, chemical methods such as ethylene oxide sterilization, and radiation methods like gamma ray sterilization.

Autoclave Steam Sterilization

The autoclave combines heat and moisture under elevated pressure. Objects are placed in the autoclave which is then sealed. Hot steam under high pressure is then forced into the autoclave. Microorganisms are destroyed in the moist heat by denaturing the enzymes and protein structures. Time and temperature vary from 15-60 minutes depending on the microorganisms being targeted.

Ethylene Oxide (ETO) Sterilization

Chemical methods of sterilization are often combined with physical methods to increase the sterility assurance level. Ethylene oxide sterilization is one such chemical method and has 5 stages: evacuation with humidification, gas introduction, exposure, evacuation, and air washes. The process takes about 2 1/2 hours. Ethylene oxide reacts with proteins, amino acids, and DNA to keep them from replicating.

Gamma Ray Sterilization

Gamma ray sterilization is performed by placing objects in the radiation field where they can receive the necessary radiation dosage. The radiation causes excitation, ionization, and free radicals, all three which damage molecules necessary for life in cells like DNA and enzymes. Gamma ray sterilization is faster than other physical or chemical methods.

If you are in need of sterility assurance level testing, submit your test request on our website or by call toll-free 1-855-377-6821.

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