Most probable number method

Clearing zones on agar plates Most probable number methods... 

Brown, E. J. and Braddock, J. F., 1990, Sheen Screen, a Miniaturized Most Probable Number Method for Enumeration of Oil-Degrading Micro-Organisms Applied and Environmental Microbiology, December, pp. 3895-3896. 

Numbers of rhizobia in a culture are estimated by the most probable number method whereby dilutions of the inoculant are used to infect sterile-grown test plants. The nodulated test plants, because they are cultured without combined nitrogen, show by their growth whether the inoculant strain fixes nitrogen. 

Bibiloni, R., Gomez Zavaglia, A., and De Antoni, G. Enzyme-based most probable number method for the enumeration of Bifidobacterium in dairy products, /. Food Prot., 64, 2001, 2001. 

Polymerase chain reaction (PCR) techniques allow one to amplify small quantities of target DNA typically by 10" to 10 times and determine in a semi-quantitative manner the presence of specific microorganisms. PCR analysis can be automated and provide turnaround times on the order of hours rather than the 3 to 5 days required for culture techniques (Atlas, 1991). Quantitation of PCR is accomplished by most probable number methods or by calibration with the function = C ,j i x 2", where C is the concen-... 

Most Probable Number Method (Multiple Tube Technique).112... 

S.3.3 Determination of Fecal Streptococci/Enterococci Using the Most Probable Number Method... 

Most Probable Number Method for the Detection of Staphylococcus... 

International Standard, ISO 9308-2 (1990). Water Quality—Detection and enumeration of coliform organisms, thermotolerant coliform organisms and presumptive Escherichia coli— Part 2 Multiple tube (most probable number) method. International Organization for Standardization, Geneva, Switzerland. 

Wu et al. [157] applied the most probable number (MPN) method to test the hypothesis that 2,6-dibromobiphenyl (26-BB) primes PCB dechlorination by stimulating the growth of microorganisms which dehalogenate 26-BB and PCBs. The experiments were conducted in anaerobic microcosms of Aroclor 1260-contaminated sediment from Woods Pond (Lenox, MA). They reported... 

The method selected shall be capable of isolating the numbers and types of organisms that have been estimated significant relative to system control and product impact for each individual system. The recommended method is membrane filtration pour plate and most probable number may be used per requirements. 

The other method of enumerating coliforms is through the use of the multiple-tube technique. This method is statistical in nature and the result is reported as the most probable number (MPN) of organisms. Hence, the other name of this method is the MPN technique. This technique is an extension of the qualitative techniques of presumptive, confirmed, and completed tests. In other words, MPN results can be a presumptive, confirmed, and completed MPNs. The number of tubes liberating gases is counted from each of the set of hve tubes. This information is then used to compute the most probable number of organisms in the sample per 100 mL. 

This distribution is called the Poisson distribution. This will be used to derive the method of estimating the most probable number, MPN. 

Populations of heterotrophs (both aerobic and anaerobic) were determined by a cultivation method on the nutrient agar with 7 day incubation at 26 C. The ammonifying, nitrifying and denitrifying bacteria, as well as those oxidizing hydrocarbons were determined on liquid media as a most probable number. The ammonifying bacteria were determined on nutrient broth by employing the... 

Fig. 2.8b. Semi-quantitativc methods or Most Probable Number (MPN).

In microbiology two fundamental types of measurements are used by the analyst. The simplest ones consist in counting colonies on culture media in a Petri dish. Another principle consists in evaluating the most probable number of microbes by inoculating sub-samples into multiple tubes. The result of the latter is given by statistical tables. For both types of methods results are only available after a few days. For the presence of very few microbes, so-called presence/absence tests have been developed by microbiologists. They are mainly used for the detection of pathogenic microbes. For the last two types... 

In all cases, the analyst will count cfp. The RMs of BCR are not certified through most probable number techniques (MPN). Microbiological CRMs are always certified through (a) given method(s) i.e. the certified value depends upon the analytical method. For all these reasons and particularities, special rules for the use of CRMs in microbiology have been developed by RIVM for BCR. The following sections dealing with the use of CRMs are directly extracted from a report prepared by J.A. van Dommelen [12]. 

Figure 2 General strategies for ELISA routine testing of seeds for virus, illustrated for lettuce mosaic virus (LMV) in lettuce and pea early-browning virus (PEBV) and pea seed-borne mosaic virus (PSbMV) in pea. Schemes Include the estimation of the percentage of Infected seeds with the most probable number (MPN) method, confirmation of doubtful results by Immunosorbent electron microscopy (ISEM) and check on actual seed transmission of the virus to seedlings ...

The above method of expressing results is not mathematically altogether correct. The average number of B. coli per cc. as thus estimated is not precisely the most probable number calculated by application of the theory of probability. To apply this theory to a correct mathematical solution of any considerable series of results involves, however, mathematical calculations so complex as to be impracticable of application in general practice. The simpler method given is therefore considered preferable, eince it is easily applied, and tiie results so expressed are readily comprehensible. 

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