Sterilization Processes

Purely physical processes such as ionizing radiation may be used for product designs and packaging materials that are impermeable to gases as long as they are "transparent" to energy of the wavelengths employed in the sterilization process.

Microwaves. The inherent advantage of microwave heating compared with other forms of heating lies in its lower power requirements. The interaction between microwaves and biological materials does not of itself appear to be lethal: rather, the lethality obtained is directly derived from the heating effect, which in turn depends on the composition of the microorganism being targeted, including its water content. Limitations related to the specifics of microwave reflectance, transmittance, and absorbance may limit applicability for device sterilization.

Pulsed-Light Systems. A novel sterilization method introduced in the past several years uses high-power electrical energy to produce intense pulses of light that are claimed to provide unique bactericidal effects. Called the PureBright system, the technology rectifies and converts normal building ac to high-voltage dc and uses it to charge a capacitor, which is then discharged through a specially designed xenon lamp unit. The high-voltage, high-current pulse applied to the lamp causes it to emit an intense pulse of light, which typically lasts for a few hundred microseconds. The light produced by the lamp includes a broad spectrum of wavelengths, from ultraviolet to infrared, with an intensity some 20,000 times greater than sunlight.

The process is reported to be highly successful in killing microorganisms, viruses, and spores, as well as in deactivating enzymes.

Potential applications include the surface sterilization of packaging materials for aseptic packaging or for bioburden reduction, and the terminal sterilization of parenterals packed in transparent plastic bags or bottles (e.g., from a blow, fill, seal machine). The photoproducts from treated substrates are reported to be generally similar to those induced by exposure to sunlight and similar to, but fewer than, those produced by thermal sterilization processes. When the process is used to sterilize the surface of opaque materials, any degradative effects would, of course, be restricted to the surface.

Disclaimer

The content of this issue is presented for general information only as perceived by the writer of the article. Reader should independently verify the correctness and accuracy of the material before using the same for any purpose whatsoever. The Company or Management or Staff of Puneet Industries or the Writer shall not be responsible for any inaccuracy or error in the article. 

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