2 replies to this topic

[Appendix G]

Hello,

 

My past validations for my batch ovens consisted of collecting data with probes to identify the coldest spots in the ovens, and then show a 7-log reduction through AMI lethality curves.

 

A new customer has requested that we establish our lower limit based on 4 standard deviations above our critical limit as compared to our process control.

 

I am confused as to how to express the data in a way that meets their requirements.  If there is more than a 2 degree difference between my coldest and hottest zones, it automatically puts my process to 170 degree minimum for recorded temperatures.

 

I am struggling to figure out a way to analyze the data to create a reasonable lower limit.

[Charles.C]

Hello,

 

My past validations for my batch ovens consisted of collecting data with probes to identify the coldest spots in the ovens, and then show a 7-log reduction through AMI lethality curves.

 

A new customer has requested that we establish our lower limit based on 4 standard deviations above our critical limit as compared to our process control.

 

I am confused as to how to express the data in a way that meets their requirements.  If there is more than a 2 degree difference between my coldest and hottest zones, it automatically puts my process to 170 degree minimum for recorded temperatures.

 

I am struggling to figure out a way to analyze the data to create a reasonable lower limit.

 

Hi AppendixG,

 

Afai understand, the basic requirement is to achieve a T vs t profile whose theoretical integrated lethality achieves a 7log reduction of the target bacterium.

The chosen critical limit / time need to be matched accordingly.

IMEX the worst case scenario (eg coldest location) is used for the profile calculation.

 

I deduce the proposed change will increase the current operational temperature compared to that based on above logic. This will further increase the log reduction assuming same time period. So I’m not sure I understand yr problem.

[moskito]

Hello,

 

me too.

A temperature probe at the coldest spot will guarantee a minimum log reduction over time needed. You have to keep all other variables constant (time, bed height or filling, heating rate etc.). Inactivation at all other positions will then be higher. So you will meet inactivation as requested from micro point of view. But some other quality parameters might be negatively influenced by higher temperature.

 

Rgds

moskito