Microwave sterilisation

Reports of sterilisation (qv) against bacteria by nonthermal effects have appeared, but it is generally beheved that the effect is only that of heating (164). Because microwave heating often is not uniform, studies in this area can be seriously flawed by simplistic assumptions of uniform sample temperature. 

Other, more recently developed, uses include microwave oven parts, transparent pipelines, chemical plant pumps and coffee machine hot water dispensers. One exceptional use has been to produce, by an extrusion moulding process, very large rollers for textile finishing for use where cast nylons cannot meet the specification. Also of growing interest are medical equipment applications that may be repeatedly steam-sterilised at 134°C, filtration membranes and cartridges for ink-jet printers. 

Rapid sterilisation of media is achieved by using microwave ovens. Most plant tissue culture media can be sterilised using a microwave, although it may not be suitable with a medium containing complex additives like oatmeal. 

In the nonchemical field cooking, drying, sterilisation and pasteurisation are areas where microwave heating is applied on a large scale. 

Human eye tissue is usually analysed for the presence of zinc salt (sterilising agent) content after acid digestion in a microwave oven at elevated temperature and pressure. This solution can also be used for analyses of other metals for medical management and post mortem studies. 

It has been suggested that developments in microwave spectrometers could provide sensors for particular chemical compounds with high specificity and sensitivity [12]. Indeed microwave spectroscopy has been used to specificaUy monitor ethylene oxide concentrations in medical sterilisation units [13]. 

Since vegetable raw materials with a sufficient microbiological quality are sometimes difficult to obtain, methods to sterilise them have been investigated. Gamma radiation, ethylene oxide or microwaves have been used. Viable organisms are successfully killed but spore-forming... 

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