the bacteria count;

'decimate' literally means ' to decrease BY a tenth' but in the modern sense it means 'destroy en masse'; could work here:

decimate - definition of decimate in English | Oxford Dictionaries
https://en.oxforddictionaries.com/definition/decimate
Historically, the meaning of the word decimate is 'kill one in every ten of (a group of people)'. This sense has been more or less totally superseded by the later, more general sense 'kill, destroy, or remove a large proportion of', as in the virus has decimated the population.

Thermal Processing - NZIFST
www.nzifst.org.nz › ... › Heat-Transfer Applications
Equivalent Killing Power at Other Temperatures Pasteurization. Thermal processing implies the controlled use of heat to increase, or reduce depending ... The object of sterilization is to destroy all microorganisms, that is, bacteria, yeasts ... times needed to reduce actual spore counts from 1012 (12 in uppercase!) to 1 (the lower, open, circles) ...

In this graph, these times are plotted against the different temperatures and it shows that when the logarithms of these times are plotted against temperatures, the resulting graph is a straight line. The mean times on this graph are called thermal death times for the corresponding temperatures. Note that these thermal death times do not represent complete sterilization, but a mathematical concept which can be considered as effective sterilization, which is in fact a survival ratio of 1:1012, and which has been found adequate for safety
http://www.nzifst.org.nz/unitoperations/httrapps2.htm

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Note added at 13 mins (2017-02-01 11:18:07 GMT)
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[DOC]Thermal Destruction of Microorganisms
web.thu.edu.tw/.../4%20Thermal%20Destruction%20of...
Thus bacteria subjected to heat are killed at a rate that is proportional to the number ... as the temperature change required to change the D value by a factor of 10. ... Organisms that can survive pasteurization temperature belong to the groups of .... So, the z-value allows us to calculate a thermal process of equivalency, if we ...

Thermal death time - Wikipedia
https://en.wikipedia.org/wiki/Thermal_death_time
Thermal death time is a concept used to determine how long it takes to kill a specific bacteria at a specific temperature. ... This would be shown either as F10121 = 10 minutes (Celsius) or F18250 = 10 minutes (Fahrenheit).

A lethal ratio (L) is also a sterilizing effect at 1 minute at other temperatures with (T). L = 10 ( T − T R e f ) ..

Survival and Heat Resistance of Salmonella enterica and Escherichia ...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3233057/ - Oldal lefordítása
Írta: Y He - ‎2011 - ‎Idézetek száma: 29 - ‎Kapcsolódó cikkek
The heat-treated samples were taken at 4 s, 10 min, 20 min, 30 min, and 1 h and ... Bacterial survival rates were calculated by enumerating viable cell counts on BHI and .... For instance, it required an average of 5.89 to 8.84 min to kill 90% of ....

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Note added at 13 mins (2017-02-01 11:18:25 GMT)
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lethal ratio or survival ratio

lower the germ count by at least one power of ten

reduce the bacterial count by at least one order of magnitude

The Keimzahl is not 'abgetötet' but 'reduziert'

That's my modest attempt.

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Note added at 1 day13 hrs (2017-02-03 00:08:00 GMT)
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which kills germs (bacteria) at a minimum at a tenfold rate