Sterilization and decontamination

Decontamination is a procedure to render safe for handling, disposal, or the subsequent processing of an article that may contain a large amount of potentially infectious organisms. Decontamination and sterilization are similar procedures, except that in the former case the bioburden is higher. In both cases, all organisms present are destroyed. However, decontamination is not expected to result reHably in the 10 probabiHty of microbial survival, as in sterilization, because of the higher bioburden. Decontamination may include sanitization and disinfection steps, but it most frequentiy involves sterilization... 

Usually, Sd-FFF separator decontamination and sterilization are needed to prevent bacterial contamination this is done by means of a 0.01% (m/v) sodium azide so-... 

Klapes, N.A. and Vesley, D. Vapor-phase hydrogen peroxide as a surface decontaminant and sterilant. Applied Environmental Microbiology 56 503-506,1990. 

The details of sterilization by chemical and physical agents are well covered in specialized textbooks (45, 52, 55, 352) as well as in textbooks of basic and applied microbiology. It is the purpose of this chapter to provide practical recommendations for decontamination and sterilization procedures as they would be practiced in the biomedical research laboratory. First, however, we outline briefly some general principles and define some commonly used terms. 

U.S. Public Health Service, National Institutes of Health. 1983. Guide to Decontamination and Sterilization Procedures. Environmental Control Section, Office of Biohazards and Environmental Control, Viral Oncology, National Cancer Institute, Division of Safety. National Institutes of Health, Bethesda, MD. 

Other applications of filters include sterilization of venting or displacement air in tissue and microbiological culture (carbon filters and hydrophobic membrane filters) decontamination of air in mechanical ventilators (glass fibre filters) treatment of exhausted air ftom microbiological safety cabinets (HEPA filters) and the clarification and sterilization of medical gases (glass wool depth filters and hydrophobic membrane filters). 

In this level, the fundamental tasks required to convert the raw materials into the final product are identified. All tasks are related to property differences. Siirola (1996) has presented the following hierarchy of property differences molecular identity, amount, composition, phase, temperature/pressure, form. This list of tasks is not very well suited for food properties. Common tasks for food processes are decontamination (e.g. pasteurization and sterilization) and structure formation (e.g. emulsification, size reduction of dispersed phase in an emulsion, crystallization, interfacial adsorption/desorption). 

When carrying out cell disruption operations it is often necessary to provide cooling of the cell concentrate due to the high pressures developed in the equipment. An additional consequence of high-pressure operation is that cell disruption equipment can generate aerosols which may be undesirable, particularly for biologically hazardous organisms. In these cases, the ability to steam sterilize the equipment is required, for decontamination, and some type of secondary containment may also be required, such as an isolator or a contained area within a facility to which access is controlled. 

For the pharmaceutical and food industries, surface finish is very important to enable effective cleaning and sterilization or sanitization. Equipment should be specified with a polished internal finish, possibly with electropolishing for critical applications, and designed with a minimum of crevices or dead spaces where dirt can collect. Welds must be finished to the same standard as the plates and ground flush with the internal surface and must be pinhole and crevice free. External surface finish may also be important for visual reasons and to enable cleaning down for surface decontamination in clean room locations. 

The product contact surfaces in this environment are typically removed for cleaning however, in some installations, the sterilization, transfer, and reinstallation of the component feed hoppers present such difficulty that these systems are decontaminated in situ with a sporicidal agent, rather than removed after each use. These units should still be removed for cleaning and sterilization on a validated periodic basis to prevent the buildup of residues that might impact their in-situ decontamination or create particle control problems. All other product contact surfaces should be sterilized prior to each use. Nonsterilized items should not be allowed to enter the ISO 5 portion of the fill zone, and sanitization is essential for all nonproduct surfaces in the fill zone, as well as the surrounding background environment. 

In addition to these regular publications, NASA publishes a variety of special publications--reports, technical handbooks, data compilations—to acquaint the non-aerospace user with NASA advances in various states-of-the-art. Examples include new developments in welding and soldering, lubricants and lubricating techniques, human factors engineering, and sterilization and decontamination. 

Where appropriate, the equipment should be designed and constructed as to allow easy and effective decontamination and/or sterilization. 

During collection, storage, and transportation, use containers constructed of materials compatible with the treatment methods utilized. Ensure the use of burnable single-use containers for waste destined for incinerators. Containers destined for steam sterilizers should allow proper treatment of the waste. Decontaminate reusable containers after each use using only approved methods. Never reuse containers unless decontaminated and before use remove all medical waste labeling. 

---