Microorganisms enumeration

Fig. 5.7 Depth distribution in the seabed of microorganisms enumerated by direct microscopic counts of cells stained by a fluorescent DNA stain. The graph shows the global data from ODP cores in a double-log plot, from the sediment surface to 800 m subsurface. Data from Parkes et al. (2000).

ASTA has also made available a manual of microbiological methods (10) which contains 22 different procedures for the detection and enumeration of microorganisms occurring in spices. A handbook on clean spices for ASTA members (11) is available. 

For those pesticides that are cometabolized, ie, not utilized as a growth substrate, the assumption of first-order kinetics is appropriate. The more accurate kinetic expression is actually pseudo-first-order kinetics, where the rate is dependent on both the pesticide concentration and the numbers of pesticide-degrading microorganisms. However, because of the difficulties in enumerating pesticide-transforming microorganisms, first-order rate constants, or half-hves, are typically reported. Based on kinetic constants, it is possible to rank the relative persistence of pesticides. Pesticides with half-hves of <10 days are considered to be relatively nonpersistent pesticides with half-hves of >100 days are considered to be relatively persistent. 

IDF (1991). Enumeration of microorganisms colony count technique at 30 °C, Standard lOOB. 

Perry-O Keeee H., Stender H., Broo-MER A., Oliveira K., Coull J., Hyldig-Nielsen J.J. Filter-based PNA in situ hybridization for rapid detection, identification and enumeration of specific microorganisms. /. Appl. Microbiol. 2001 90 180-189. 

Table 4 Media for the Enumeration and I.solation of Soil Microorganisms ...

In any event, the mere inclusion of microorganisms in the species to be enumerated makes a catalogue of the existing species for from being an affordable enterprise. Dealing with viruses is especially difficult although they do not live as isolated entities, they are found widespreadly in the oceans, possibly involved in regulating the biodiversity (Fuhrman 1999). 

As air is drawn towards the impeller blades, it is subjected to centrifugal acceleration. Viable microorganisms in the sampled air are impacted at high velocity onto the surface of the agar strip. After sampling, the strip containing the nutrient is incubated at 30 to 35°C for days. The colonies can be enumerated by visual examination and the results should be recorded. Sampling time with the RCS should be 2 min (= 80 1 air). 

All colony-forming units (CPUs) are enumerated if present. Isolates recovered in the level I and level II areas are identified as to genus and species. The summary of airborne microorganisms is monitored during the manufacturing of (product name) stability batch. 

Walker, J. D. Colwell, R. R. (1976b). Enumeration of petroleum-degrading microorganisms. Applied and Environmental Microbiology, 31, 198—207. 

King, R.J., Short, K. A. Seidler, R.J. (1991). Assay for detection and enumeration of genetically engineered microorganisms which is based on the activity of a deregulated 2,4-dichlorophenoxyacetate monooxygenase. Applied and Environmental Microbiology, 57, 1790-2. 

While directly quantifying the numbers of microorganisms attached to the surface of a polymer by enumeration of colonies following incubation on a suitable medium has been widely used to indicate the amount of growth supported on the polymer surface (Christensen et al., 1995), it has a number of severe limitations. The technique depends on a... 

Elect, G.H. (1993) The microorganisms of winemaking - isolation, enumeration and identification. In G.H. Fleet (Ed.), Wine Microbiology and Biotechnology (pp. 1-25). Reading Hrawood Academic. 

The sampling and enumeration of microorganisms is perhaps more prone to inadvertent contamination than the aseptic process itself... 

Krumbein, W.E. and Altmann, H.J., 1973. A new method for the detection and enumeration of manganese oxidizing and reducing microorganisms. Helgol. Wiss. Meeresunters., 25 347—356. 

There are many situations in which microorganisms must not only be detected and enumerated but where they must also be identified either to make a... 

FLEX 1 All foods and water, excepted worn water Enumeration of microorganisms Culture... 

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