Cold sterilization, method

Ethylene oxide sterilization is suitable for both small-scale and large-scale applications. It is primarily a method of cold sterilization and has so many associated complications that it is never used in preference to thermal sterilization for heat-stable materials. Sterilization by gamma radiation is more reliable than ethylene oxide for cold sterilization, and it is simpler to control. It is, however, limited by suitability of materials and only operates on a large scale. 

A number of sterilization methods are used for medical devices. Hiese indude gamma inadiation, steam, electron beam, cold plasmas, and antibacterial agents. Because of the importance of device sterilization to the health of the patient, and because of the potential of sterilization methods to damage polymeric biomaterials, sterilization of medical devices is a field unto itself and is described elsewhere. 

Generally, sterility is synonym with the absence of any viable microorganisms including their spores. Currently, the available sterilization methods include heat sterilization (steam and hot-air sterilization), cold sterilization (gas sterilization, sterilization by ionizing radiation), sterilization by aqueous solution (aldehydes, peracetic acid, hypochlorite, hydrogen peroxide), and sterilization by filtration methods. The choice of method is based on recommendations in medicinal literature, legal requirements, and the compatibility of a medical product with the method used. The decision for a particular method has to take the following factors into consideration [954] ... 

Yokota [2.1] sprays the liquid to be frozen in to a film of cold n-hexane, which flows down the inner wall of a conical vessel. The frozen particles are sieved off. With this method, two problems need to be solved (i) The droplet size cannot be influenced, product parts can be extracted, and the product and n-hexane must to be completely separated, and (ii) the process must be sterile. 

Ethylene oxide is a gas that is used in the sterilization of equipment too large for other techniques, and for sterilizing rubber, plastic goods, and other materials that are damaged by heat and not adequately disinfected by other cold methods. 

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