Sterilization, radiation

Radiation crosslinking is another way to tailor properties to specific applications. High-energy radiation provides a dean and cost-effective method to achieve this means. The technique has been applied in the crosslinking of high-purity medical 

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Several methods have received considerable research attention as alternatives to salt curing. These include use of sodium bisulfite as a disinfectant to allow preservation with or without decreased salt in a brine cure use of disinfectants such as quatenary amines for temporary preservation in direct shipping to the taimery from the packing plant (see Disinfectants and antiseptics) preservation of hides by radiation sterilization (see Sterilization techniques) and substitution of materials such as potassium chloride for sodium chloride. These methods have found only limited commercial success. 

Medical and health-care related appHcations consume about 21,000 t of polycarbonate aimuaHy. Polycarbonate is popular because of its clarity, impact strength, and low level of extractable impurities. Special grades have been developed to maintain clarity and resistance to yeHowing upon gamma radiation sterilization (qv) processes. Leisure and safety appHcations are many and varied, accounting for about 22,000 t of consumption aimuaHy. The... 

As of 1996, purchased by Steris Corp. (Ohio). Radiation sterilizer. 

Hemmerich, K. J., Polymer Materials Selection for Radiation-Sterilized Products, MD DI, Feb. 2000. 

In radiation sterilization of disposable supplies such as hypodermic syringes, needles, catheters, and sterile dressings in medicine. 

In radiation sterilization, a plastic (olien perspex) dosimeter which gradually darkens in proportion to the radiation absorbed gives an accurate measure of the radiation dose and is considered to be the best technique currently available for following the radiosterilization process. 

Biological indicators (Bis) for use in thermal, chemical or radiation sterilization processes consist of standardized bacterial spore preparations which are usually in the form either of suspensions in water or culture medium or of spores dried on paper, aluminium or plastic carriers. As with chentical indicators, they are usually placed in dummy packs located at strategic sites in the sterilizer. Alternatively, for gaseous sterihzation these may also be placed within a tubular hehx (Line-Pickerill) device. After the sterilization process, the aqueous suspensions or spores on carriers are aseptically transferred to an appropriate nutrient medium which is then incubated and periodically examined for signs of growth. Spores of Bacillus stearothermophilus in sealed ampoules of cultrrre medium are used for steam sterilization morritoring, and these may be incubated directly at 55°C this eliminates the need for an aseptic transfer. 

Radiation sterilization Radiochromic chemical Plastic devices impregnated with radiosensitive chemicals which undergo colour changes at relatively low radiation doses Only indicate exposure to radiation... 

Mclnnes, D.O. and T.T.Y. Wong. 1990. Mediterranean fruitfly interference of oviposition by radiation-sterilized females in field cages. Entomol. Exper. Appl. 56 125-130. 

The launch of new resins being rare, progress on materials intended for medical applications is by way of formulation, alloys and modifications of existing resins. Thus, new radiation-stable polypropylene grades are available for the manufacture of cups, boxes, baskets, mixers, etc. that are radiation sterilized. And polyesters with better environmental stress cracking resistance are extending their potenti in the area of medical testing. 

Judiciously selected grades provide good impact and fatigue resistance, good stiffness and impact balance, suitability for food contact, low extractables,good organoleptic properties, the possibility of autoclave and radiation sterilization in the presence of aqueous solutions. .. 

Unlike polyethylene, polypropylene is not crosslinked and deteriorates. The action of high-energy radiation depends in a complex way on the power, dose and wall thickness of polypropylene. Thus, it is often advised to avoid doses greater than 1 kJ/kg (0.1 Mrad). However, special grades are marketed for radiation sterilization but doses of the order of 25kJ/kg (2.5 Mrad) can lead to a certain brittleness after storage of several months. 

The technology has been developed mainly for meats, poultry, and certain seafoods in the United States, and radappertized foods were successfully used in space missions [116]. Similar radiation-sterilized products were manufactured by the Atomic Energy Corporation of South Africa for hikers [117]. 

Radiation sterilization of deep frozen meals prepared for hospital patients whose immune systems have been suppressed is approved in several countries such as the United Kingdom, The Netherlands, and the Federal Republic of Germany. 

Thayer et al. (26) reported the results of nutritional, genetic, and toxicological studies of enzyme-inactivated, radiation-sterilized chicken meat. The study included four enzyme-inactivated chicken meat products 1) a frozen control, 2) a thermally processed product (llS.b C), 3) a gamma-sterilized product, and 4)... 

Radiation Sterilization Use of radiation to cause a plant or animal to become incapable of reproduction tire use of radiation to kill all forms of life, especially bacteria, in food and surgical sutures. 

Welle, F (2005), Migration of radiolysis products from radiation-sterilized plastics, Pharm. Ind., 67(8), 970-972. 

Janimak, J. J., and Marteleur, M. (2004), On the stability of cerium oxide glass for terminal radiation sterilization, Rad. Phys. Chem. 71,195-198. 

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