Many kinds of microbes are pathogens, meaning they are capable of causing disease to other organisms. Sterilization processes, such as exposure to heat, destroy these pathogens. D-value refers to decimal reduction time - The time required at a certain temperature to kill 90% of the organisms being studied. Thus after an organism is reduced by 1 D, only 10% of the original organisms remain. The population number has been reduced by one decimal place in the counting scheme. Generally, each lot of a sterilization-resistant organism is given a unique D-value. When referring to D values it is proper to give the temperature as a subscript to the D. For example, a hypothetical organism is reduced by 90% after exposure to temperatures of 300 degrees Fahrenheit for 2 minutes, Thus the D-value would be written as D300F = 2 minutes. D-value determination [1] is often carried out to measure a disinfectant's efficiency to reduce the number of microbes, present in a given environment.

D-VALUE in meteorology refers to the deviation of actual altitude along a constant pressure surface from the standard atmosphere altitude of that surface.

D-Value in transport is a rating that is typically attributed to mechanical couplings, and reflects dynamic loading limits between truck and trailer. The corresponding formula, required to interpret the D-value of a coupling, is: D=(Gross Vehicle Mass X Gross Trailer Mass)/(Gross Combination Mass). Note that GVM refers to the towing vehicle, GTM refers to the axle loads only of the towed vehicle, and GCM refers to the total mass of the combination.

[edit] See also

• Z-value

This bioinformatics-related article is a stub. You can help Wikipedia by expanding it. v • d • e