Fungi, microbial testing

Microbial testing for aerobic and anaerobic bacteria and fungi is typically conducted. Specific species searched for include ... 

Disinfection tests can be classified according to the test organism, ie, whether the test employs certain species of bacteria, fungi, or vimses classified as to whether it is a static test or a cidal test, as in a bactericidal vs bacteriostatic test or sporicidal vs sporistatic test or classified as to whether it is a microbial reduction test or an end-point test where all the organisms in the test are apparently killed. Procedures may be distinguished by in vitro or in vivo testing. Another way to consider tests is whether they are screening tests, practical type laboratory tests, or field tests. 

The types of microorganisms found in various products are Pseudomonas species, including Pseudomonas aeruginosa, Salmonella, species, Staphylococcus aureus, and Escherichia coli. The USP and other pharmacopoeias recommend certain classes of products to be tested for specified microbial contaminants, e.g., natural plant, animal, and some mineral products for the absence of Salmonella species, suspensions for the absence of E. coli, and topically administered products for the absence of P. aeruginosa and S. aureus. Emulsions are especially susceptible to contamination by fungi and yeasts. Consumer use may also result in the introduction of microorganisms. For aqueous-based products, it is therefore mandatory to include a preservative in the formulation in order to provide further assurance that the product retains its pharmaceutically acceptable characteristics until it is used by the patient. 

Source. Enzymes for food applications come from all three kingdoms plant, animal, and microbial. Traditionally used plant and animal enzymes are the plant proteases such as papain, ficin and bromelain, plant amylases from malt, and animal rennin which is used in cheese manufacture. Microbial cells are the usual and most promising future source of industrial enzymes. Estimates of the number of microorganisms in the world tested as potential sources of enzymes fall around 2% with only about 25 organisms, including a dozen or so fungi, currently used for industrial enzymes. 

Phenol coefficient tests were developed in the early 20th century when typhoid fever was a significant public health problem and phenolics were used to disinfect contaminated utensils and other inanimate objects. Details of such tests can be found in earlier editions of this book. However, as non-phenolic disinfectants became more widely available, tests that more closely paralleled the conditions under which disinfectants were being used (e.g. blood spills) and which included a more diverse range of microbial types (e.g. viruses, bacteria, fungi, protozoa) were developed. Evaluation of a disinfectant s efficacy was based on its ability to kill microbes, i.e. its cidal activity, under environmental conditions mimicking as closely as possible real life situations. As an essential component of each test was a final viability assay, removal or neutralization of any residual disinfectant became a significant consideration. 

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