Sterilisation WS W10

Question 1

Define the D value for sterilisation technique and why i it important

Answer 1

a measure of the effectiveness of a sterilization process.

It represents the time required to reduce a microbial population by 90%

allows manufacturers to determine the time or dose required to sterilize products reliably, ensuring a consistent and validated sterilization process

Question 2

Using the value of D=0.8, how long will it take at 121degrees to reduce the bioburden of micro-organism X from 10^7 to 10^1

Answer 2

10^7 to 10^1 = 6 x DR

6x0.8 =4.8 mins

Question 3

How many micro-orgs will remain after 8 mins at 121degrees. D=0.8

Answer 3

Total time/D

8/0.8

Question 4

Define the Z value and why is it so important

Answer 4

is the temperature change required to achieve a tenfold (1-log10) reduction in the D value of a microorganism.

indicates how sensitive a microorganism is to changes in temperature.

A smaller Z value = more sensitive to temperature changes

Question 5

The D value of micro-organism X at 116degrees is 4.1 minutes. Calculate the Z value for X.

Answer 5

Z=T1-T2 / log10(DT2)-log10(DT1)

-> 121-116 / log4.1-log0.8

-> 5/0.613–0.097

= 7 degrees

Question 6

Using the Z value of 7 calculate the D value at 107degrees.

Previous question : The D value of micro-organism X at 116degrees is 4.1 minutes.

Answer 6

D1 = 4.1
T1 = 116
T2 =107
Z=7

D2 = 4.1 x 10^(116-107 / 7)

-> 4.1 x 10^9/7

-> 4.1 x 10^1.28

= 80 mins

Question 7

Explain the F0 concept for a sterilisation technique, why is it mportant

Answer 7

indicates the equivalent time at a reference temperature required to kill a specific microorganism or set of microorganisms.

It’s used to evaluate the effectiveness of the heat treatment applied to a product

ensure that the sterilization process is effective, particularly when heat is used to kill microorganisms in products like canned foods or medicines