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In general, an n-log reduction means that the concentration of remaining contaminants is only 10 −n times that of the original. So for example, a 0-log reduction is no reduction at all, while a 1-log reduction corresponds to a reduction of 90 percent from the original concentration, and a 2-log reduction corresponds to a reduction of 99 ...
From this perspective, D-values can be understood as roughly analogous to half lives of radioactive substances, however a half life involves a reduction of 50% rather than 90%. The half life is actually roughly 30% (log 10 2 ≈ 30.103%) of the D-value, so if D = 10 minutes, the number of living microorganisms will be halved in about 3 minutes.
Z-value is a term used in microbial thermal death time calculations. It is the number of degrees the temperature has to be increased to achieve a tenfold (i.e. 1 log 10 ) reduction in the D-value . The D-value of an organism is the time required in a given medium, at a given temperature, for a ten-fold reduction in the number of organisms.
In autecological studies, the growth of bacteria (or other microorganisms, as protozoa, microalgae or yeasts) in batch culture can be modeled with four different phases: lag phase (A), log phase or exponential phase (B), stationary phase (C), and death phase (D). [3] During lag phase, bacteria adapt themselves to growth conditions.
The target of reduction in canning is the 12-D reduction of C. botulinum, which means that processing time will reduce the amount of this bacteria by a factor of 10 12. The D R for C. botulinum is 0.21 minute (12.6 seconds). A 12-D reduction will take 2.52 minutes (151 seconds).
A tenfold dilution for each step is called a logarithmic dilution or log-dilution, a 3.16-fold (10 0.5-fold) dilution is called a half-logarithmic dilution or half-log dilution, and a 1.78-fold (10 0.25-fold) dilution is called a quarter-logarithmic dilution or quarter-log dilution.
In microbiology, a colony-forming unit (CFU, cfu or Cfu) is a unit which estimates the number of microbial cells (bacteria, fungi, viruses etc.) in a sample that are viable, able to multiply via binary fission under the controlled conditions.
Size Reference Flatworm animal: Eucestoda: Tapeworm: length (maximum) 25 m: Eucestoda: Nematode animal: Loa loa: Loa loa: length (female) 20–70 mm: Loa loa: Arthropod animal: Cymothoa exigua: Tongue-eating louse: length (female) 8–29 mm: Cymothoa exigua: Nematode animal: Enterobius: Pinworm: length (female) 8–13 mm: Pinworm (parasite ...