Jump to content

  • Quick Navigation
- - - - -

How to calculate The Least Sterilizing Value (F0) for Water Activity?

Water Activity Product least sterilizing value F0 F0 value

  • You cannot start a new topic
  • Please log in to reply
2 replies to this topic


    Grade - Active

  • IFSQN Active
  • 3 posts
  • 0 thanks

  • Korea - South
    Korea - South

Posted 03 November 2015 - 07:15 AM

Hi, I am Garnet.
My company makes Red Bean Paste.
but I don't know how to calculate The Least Sterilizing Value.
Please help me.
Product's container type is Flexible Pouch.
Volume : 176.4 FL OZ (5kg)
finished equilibrium pH of the product after processing is 6.8
Maximum water activity : 0.9
heating medium : steam
process mode : Steam Jacketed Kettle
temperature of the product in the container at the end of the hold time : 176.0 Fahrenheit
Start Temp (when putting the product to container) 194 °F
Process Time (Hold time) : 30 min
Process Temp : 176 ~ 212 °F
Temp of Process Sterilization
: above 176°F 
(for 30 minutes)
Well. somebody help me.
Can Anybody calculate the least sterilizing value?
('The Least Sterilizing value' and 'F0 value' are same thing?) 
Please tell me.
If you ask more information. I will reply.
I need the value. 


    Grade - FIFSQN

  • IFSQN Moderator
  • 18,874 posts
  • 5253 thanks

  • Earth
  • Gender:Male
  • Interests:SF

Posted 03 November 2015 - 06:40 PM

Hi Garnet,


Not too sure about the Title.  Water activity ? :smile:  (But see PS below!)

As I understand, the “least sterilizing value (LSV)”, is typically determined by a so-called “Expert Authority” for the purposes of processors registering their process, eg with FDA.

The EA apparently makes this decision based on heat penetration data as supplied by the processor and knowledge / experience of the product/system to be used.


Unfortunately I have found specific definitions for LSV elusive. The only one I could find was –


Fo (LEAST STERILIZING VALUE) The number of minutes at a reference temperature of 250 degrees Fahrenheit required to kill a known population of microorganisms with a z value of 18 degrees Fahrenheit. This value must be obtained from a scientifically qualified process authority



afaik sterilization processes for Low-acid products usually involve 2 contributory factors to the overall required lethality value – (a) a safety contribution based on a 12D reduction of any existing C.botulinum (typically set at F0 =3) and (b) a non-safety component to ensure commercial sterility.


It is unclear to me if the LSV includes (a+b) or only refers to (a).


The data for LSV in the attached example  below rather implies (a,b) but is not definitive. If it does include (b) the determination looks non-simple.


Maybe you, or any canning/pouching people here, can clarify ?


Attached File  Principles-of-Thermal-Processing,2005.pdf   95.18KB   82 downloads


PS - Just realized the possible significance of yr titling water activity ! -


Edited by Charles.C, 03 November 2015 - 08:56 PM.

Kind Regards,



Thanked by 1 Member:


    Grade - Active

  • IFSQN Active
  • 3 posts
  • 0 thanks

  • Korea - South
    Korea - South

Posted 04 November 2015 - 08:39 AM

Thank you!!

I appreciate to your prompt reply.

seems like I should study more. :)


Thank you for your help again.

Also tagged with one or more of these keywords: Water Activity Product, least sterilizing value, F0, F0 value

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users