2.2 Bacteria levels in the D-2 standard
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Statutory Documents - IMO Publications and Documents - Circulars - Ballast Water Management - BWM.2/Circular.42/Rev.2 – International Convention for the Control and Management of Ships' Ballast Water and Sediments, 2004 – (9 December 2020)... - Annex 2 – Technical Discussion for the Guidance to Ballast Water Sampling and Analysis for Trial Use in Accordance with the BWM Convention and Guidelines (G2) - 2 Indicative Analysis: Methodology and Approaches - 2.2 Bacteria levels in the D-2 standard

2.2 Bacteria levels in the D-2 standard

  2.2.1 Bacterial levels could be tested by a wealth of available portable methods. However, as the D-2 standard for bacteria is measured in colony forming units (CFU), the systems utilized may have to include a specific incubation time of the samples, which for commercially available systems is never shorter than four hours. Therefore, the time it takes for incubation limits the use of such systems for indicative analysis.

  2.2.2 Advances in fluorometric diagnostics have resulted in a methodology that identifies the presence or absence of bacteria in a sample of the ballast water discharge. This methodology is based upon the detection of enzymes produced by the target bacteria in unconcentrated fresh water or marine samples and presently easily portable test kits for E. coli and Enterococci are available. This method can identify low levels of bacteria in water samples in less than 10 minutes, but the results are only semi-quantitative, i.e. a low level reading equates to a low level of bacteria. However, although the presence of bacteria can be shown, whether or not these organisms are living (i.e. form colonies) cannot be proven with this method at the present time. These diagnostic methods could be used in indicative analysis if very large numbers of organisms are identified.

Parent topic: 2 Indicative Analysis: Methodology and Approaches
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