Sterilization microorganism sensitivity

Ethylene Oxide. Ethylene oxide, C2H4O. is a colorless flammable gas that liquefies at I2°C. It has been used to sterilize temperature-sensitive medical equipment and certain pharmaceuticals that cannot be heat sterilized in an auuxrlavc. Ethylene oxide diffuses readily through porous materials and very effectively de.stroys all forms of microorganisms at ambient temperatures."... 

Continuous processes have an even better productivity, especially for slow fermentations. Their disadvantages are their sensitivity to contamination by unwanted microorganisms, and to accumulation of side products, which can interfere with the fermentation. In the continuous mode, the starting culture and medium are filled into the reactor and more nutrients are added continuously as the cells are growing. Part of the fermentation broth is removed at a suitable rate to keep the volume constant. All media must be sterilized before they enter the reactor, which can lead to problems during routine operation. 

Lesions found to be inflammatory at biopsy should be sent sterile from the OR to the microbiology laboratory for cultures. Cultures are more sensitive than tissue stains for nearly all microorganisms that grow in vitro. 

The sensitivity of GC enables the amount of microorganisms to be determined by analysis of the products of their metabolism. Analysis of lethogenic Clostridia has shown that the presence of bacteria in a culture medium in amounts less than 10 per miQilitre is sufficient for their identification [213]. GC may be used to check the sterility of... 

Even when preservatives are included in single-dose presentations (as they often are), their efficacy against particular types of microorganisms can never be legitimately used as an excuse for tolerating in>process contamination by preservative-sensitive types. Nor can the inclusion of preservatives in products be used to shorten or reduce the intensity of sterilization processes applied to products or their containers to lower than normal levels of sterility assurance. Preservatives are supplementary, not intrinsic to industrial-scale processes of achieving sterility. 

By reference to the tables in Appendix Bl of the Guidelines, dose.s of radiation appropriate to SALs of I O - and can be detarmined. The second practical consideration is to test the hypothesis by irradiating one hundred items at the tabulated 10 dose. Unless the actual distribution of radiation sensitivities of the microorganisms on the items is more resistant than the "standard but arbitrary" distribution, then all one hundred items will be sterile when tested. This then supports the tabulated dose required to achieve a 10 SAL. 

Investigations should address the type of microorganisms isolated from the failed filling trial, their likely sources, their sensitivities to the antimicrobial characteristics of products that have been filled on the line, and most importantly their history of past occurrence. For instance, microorganisms that have been detected and represented as laboratory contamination in past Tests for Sterility should be considered as genuine product contaminants in those batches passed on retest. Batch withdrawal should be undertaken if they are also capable of surviving to any extent in the product. Identities should be at least to species level in failed filling trials. 

When applied to the finished product, a sterility test should be regarded as only the last in a series of control measures by which sterility is assured. Compliance with the test does not guarantee sterility of the whole batch since sampling may fail to select non-sterile containers and also the culture method used have limits to their sensitivity that will not necessarily permit growth of all microorganisms. 

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