Figure 7.1

A suspension of 10⁶ Bacillus cereus endospores was put in a hot-air oven at 170°C.Plate counts were used to determine the number of endospores surviving at the time intervals shown.
-In Figure 7.1,the decimal reduction time (D value)for the culture,which is defined as the time to reduce a population by one log,is approximately
A)0 minutes.
B)10 minutes.
C)30 minutes.
D)40 minutes.
E)60 minutes.

Question

Figure 7.1
  
A suspension of 10⁶ Bacillus cereus endospores was put in a hot-air oven at 170°C.Plate counts were used to determine the number of endospores surviving at the time intervals shown.
-In Figure 7.1,the decimal reduction time (D value)for the culture,which is defined as the time to reduce a population by one log,is approximately
A)0 minutes. 
B)10 minutes. 
C)30 minutes. 
D)40 minutes. 
E)60 minutes.

Quizplus · Accepted Answer

The decimal reduction time (D value) is the time required to reduce a microbial population by 90% or one log cycle. In the context of the question, without seeing Figure 7.1, the correct answer cannot be directly determined. However, based on the typical context of such questions, a D value of 10 minutes is a common estimate for many bacteria under moderate conditions, hence the selection of this option for the purpose of this exercise.

Figure 7.1 a Suspension of 10⁶ Bacillus Cereus Endospores Was Put in Cereus