Sterilisation steam

G. B. Phillips and W. Miller, Validation of Steam Sterilisation Technical Monograph 1, Parenteral Dmg Association, 1978. 

Steam Sterilisation and Sterility Assurance Association for Advancement of Medical Instmmentation, Arlington, Va., ANSI/AAMI ST46,1993. 

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. 

Medium containing up to 35% glucose is steam sterilised by a steam jacket around a conventional stirred tank reactor. pH adjustment starts as the medium cools and is maintained at 65. Vigorous aeration is again required. Inoculation is usually by using a mycelial suspension. Under these conditions a 30% glucose solution can be almost quantitatively converted to sodium gluconate within 36 hours. 

Industrial bioreactors can withstand up to 3 atmospheres positive pressure. Large fermenters are equipped with a lit vertical sight glass for inspecting the contents of the reactor. Side parts for pH, temperature and dissolved oxygen sensors are a minimum requirement. A steam sterilisation sample port is provided. Mechanical agitators are installed on the top or bottom of the tank for adequate mixing. 

The treatment of the above mentioned membranes in pure steam for 100 hours at 150°C and 300°C did not induce any pore-growth either. This is a very important result, because such a treatment is common in steam-sterilisation. 

Cross J. Steam sterilisable ultrafiltration membranes. Manuf Chem 1989 60(3) 25-27. 

Runia, W.T. (1983) A recent development in steam sterilisation. Acta Horticulturae 152, p. 195. 

Steam autoclaving may be used for both filled (water-based) and empty packs and components which are subsequently assembled by aseptic processing. The plastics which can be steam sterilised include HDPE, PP, PC, PA and, under selected conditions, plasticised PVC. 

Cast polypropylene (PP) is extensible, moisture-resistant, clear and seals at temperatures above those used in steam sterilisation. Oriented PP is strong and can be used in thin gauges. Unless coated or coextruded the film cannot be heat sealed without distortion. OPP is very clear, but can also make an opalescent film. Has a similar degree of inertness to HDPE. 

Another tough, clear film. Withstands steam sterilisation. Rather expensive. Only fair moisture resistance but good scuff resistance. Used in some laminations. 

Very tough with paper-like appearance. Used in medical packaging as a steam sterilisable porous material, (excludes bioburden). Based on HDPE. Has high strength. 

Steam sterilisation (autoclave) Ethylene oxide (ETO) sterilisation Gamma irradiation Preferred method, established effectiveness No closure moisture level increase No closure moisture level increase Increased closure moisture level giving potential problems in lyophilised products Ethylene oxide sorbs into closures Not suitable for all rubber formulations... 

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