dilution plating

dilution plating

the number of MICROORGANISMS in a given sample can be determined by plating dilutions of the sample on to a suitable MEDIUM. Measured amounts of each dilution can be plated on AGAR plates. After incubation, the number of colonies growing is counted. It is assumed that each microorganism in the original sample will give rise to a single colony on the plate. Thus by allowing for the dilution factor, the number of colony-forming units per cm3 (cfu.cm-3) in the sample can be obtained. Although this plating technique is not a very exact method for the enumeration of microorganisms, it is generally satisfactory for routine use.
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We then carefully swabbed the circles and did dilution plating to determine the number of viable bacteria recoverable from the surface.
5] cfu's) were exposed to the films at room temperature and after 2 minutes the number of viable CFUs remaining was determined by dilution plating.
were purified by dilution plating and identified by their morphologic and biochemical profiles, including development of blue color on L-canavanine-glycine bromothymol blue medium.
Stock cultures of all of these strains were maintained by repeated subculture on plates of nutrient agar (Oxoid, Basingstoke, UK), using the streak dilution plating method (14) with incubation for 18-24 h at 37[degrees]C.
5); however, the results from shoot imprinting were not consistent with the population numbers measured by dilution plating.
The inconsistency between methods was not unexpected, as previous comparisons of data obtained by shoot imprinting with population numbers obtained by dilution plating have shown that there is no direct relationship between numbers of colonization sites and population levels (Giesler et al.