Recontamination

Whereas the underlying separation or purification technology may be straightforward, the purity achieved is often far less than that which the separation processes are capable of producing. More often than not, recontamination by impurities released by the materials of constmction used in the purification, storage, and deUvery equipment represents the tme limit to the purity that can be achieved in practice. 

Specialty Gases. The purity of specialty gases depends on the systems and procedures adopted by the distributors for bulk gas supply and cylinder preparation, filling, and deHvery. The distributors need to foUow strict cylinder selection, preparation, and filling procedures to ensure the quaHty of the products. Most of the precautions taken into consideration in the bulk gases deHvery system are also appHed for specialty gases to eliminate recontamination. 

Because of the HW temperatures involved, metal basket strainers tend to be popular, but in-line bag filters using high temperature-resistant bags are also widely used. The benefit of strainers and bags over cartridges and candle filters is that where iron oxide transport is the primary problem, the iron particles are trapped inside and cannot fall off or otherwise recontaminate the CR system. 

Effective prewashing can be performed for a set of plates however, proper storage mnst be gnaranteed to avoid any recontamination. A special simnltaneons separating chamber (Desaga) of the same dimensions as the standard chambers but with vertical grooves in the transverse sides can hold up to five plates. This chamber is effectively employed for prewashing of plates if filled with a suitable solvent. 

Recompression evaporators, in sodium chloride solution mining, 22 803, 804 Reconfigured Integrated Two-Stage Liquefaction (RITSL), 6 843 Recontamination prevention technologies, 13 463... 

A final point to remember is that after the proper (i.e., the one fitting the conditions and requirements of a given surface) cleaning procedure has been completed, care must be taken to ensure that the surface will not be recontaminated during subsequent storage. 

In cases where a virus inactivation or removal process is performed during manufacture, measures should be taken to avoid the risk of recontamination of treated products by non-treated products. 

Groundwater recontamination, as might be seen with traditional pump-and-treat systems, does not occur when all phases are treated together. 

Irradiation can be applied through any packaging materials including those that cannot withstand heat. This also means that radiation treatment can be performed after packaging, thus avoiding recontamination or reinfestation of the product. 

Cultured dairy foods seldom cause foodborne illness in the consumer. If an active starter culture is used, common foodborne pathogens, even if present in the milk, do not grow well and often are inactivated during the fermentation or early during the storage life of the product. Even if some cultured products are recontaminated after manufacture, pathogens generally do not survive well. Several examples will illustrate these points. 

Semi-quantitative results obtained from XPS analyses after Ar+ sputtering (4 kV, 100 iA) and using the Scofield sensitivity factors see J.H. Scofield. J. Electron. Spectros. Rel. Phenom., 8,129 (1976). Overestimated values C recontamination of the surface due to the use of separate sputtering and analysis chambers. 

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