Microbial testing

Calibration and maintenance programs [45], challenge tests [2], accelerated shelf life tests [53], auditing [2], sensory tests [46], microbial tests [47]... 

Nestmann ER, Matula TI, Douglas GR, et al. 1979. Detection of the mutagenic activity of lead chromate using a battery of microbial tests. Mut Res 66 357-365. 

New microbial testing methods are coming to the market place based on advanced technologies. These new tests represent improvements in the timeliness and quality of testing. 

Dosage Form Microbial Test Testing Plan Test Intervals ... 

Although not within the scope of this chapter, it is worth noting that the PAT initiative also involves the development of rapid microbiological methods [46], the word rapid in this context being the analogue to process analytical for chemical and physical measurements. The scope of microbial testing within this initiative includes... 

Svensson, K. and Pell, M. 2001. Soil microbial tests for discriminating between different cropping systems and fertiliser regimes. Biology and Fertility of Soils 33(2) 91-99. 

It is because of these enormous F110 values obtained during overkill cycles that several experts strongly advocate the use of endotoxin challenge studies instead of microbial tests. 

Typical testing for stability studies includes appearance, potency, chiral assay, and related substances (impurities, degradation products, and contaminants) by HPLC assay, water content by Karl Fischer, identification by NIR or NMR, melting point by DSC, plus microbial testing. 

Chapter 20. Parish, W. E. Immunological tests to predict toxicological hazards to man. Chapter 21. Venitt, S. Microbial tests in carcinogenesis studies. 

Chen, C.-Y., Chen, J.-N. and Chen, S.-D. (1999) Toxicity assessment of industrial wastewater by microbial testing method, Water Science and Technology 39(10-11), 139-143. 

Quantal toxicity tests employing organisms such as daphnids or fish do not alter the concentration of contaminant(s) in a given volume of water because they are directly introduced into their respective experimental containers. In contrast, bioassays undertaken with algae and bacteria somewhat dilute the test material since they must be introduced into test containers (i.e., flasks, tubes or microplate wells) via a certain volume of inoculum. In such tests, the volume share of the test culture can sometimes reach 20 % in the test preparation, which corresponds to a dilution of 1 1.25 (Tab. 2). This dilution stage is therefore the highest concentration that can be examined with such microbial tests. 

Procedures—An underutilized practice in validation is the SOP, whereby repetitive activities can be defined. The use of SOPs increases reproducibility of execution and allows for further brevity in both protocols and reports. Procedures make everyone who is involved with the project substantially more efficient, and should be employed wherever possible. Practices such as calibration of instrumentation, biological indicator placement, sampling of validation batches, and microbial testing are clear candidates for inclusion in SOPs. Among the more innovative uses is the inclusion of standardized validation acceptance criteria for similar products. 

Microbiological tests are substantially less reproducible than chemical tests, thus the quantifiable results of any microbial test are less reliable. 

Microbial tests are substantially less certain than chemical ones, especially when they entail quantification. Microbial limits must be looked at with some skepticism the real value might be something quite different—either higher or lower—than the reported one. Consider any absolute number with some caution the answers are never as clear as they might seem with microbiology. When it comes to enumeration, microbiology can be less than a pure science. 

In answer to the first question, the Committee suggests a two-tier system of inexpensive, short-term, sensitive mutagenicity tests that could be widely applied to identify substances that may represent a mutagenic hazard. The first tier uses one microbial test and two mammalian cell-culture tests. If the results of this tier are inconclusive, a Drosophila test (the second tier) is used. If the results are still insufficient for a manufacturing or control decision, further tests cure available, including those using mice. The test scheme is presented later in this summary and in more detail in Chapter 9. 

Microbial tests based on reverse mutation are specific, because a unique mutation must undergo precise reversion.423 This may be a limitation, in that only one genetic end point is monitored, although little empirical evidence supports this criticism. A prokaryotic or eukaryotic cell apparently uses a number of pathways at the same time to cope with adducts that cure covalently bound to DMA. 

In addition to plant activation of promutagens, such as dimethyInitrosamine,16 that are also activated in mammalian metabolism, the possibility of unique abilities of plants to activate some substances warrants attention. For example, interest in metabolism of promutagens by plants was stimulated by the evidence11 0 354 that maize can activate the nonmutagenic herbicide atrazine and some related compounds to substances that cure detectable as mutagens in microbial tests. Atrazine was also mutagenic in the waxy locus test in the maize plants themselves.354... 

Microbial test with and without metabolic activation ... 

Sekizawa, J. and Shibamoto, T. (1982) Cenotoxicity of safrole-related chemicals in microbial test systems. 

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

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