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F0, B* and C* for ESL Dairy Products

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    Posted: 14 Nov 2011 at 9:02pm
I have added a highly flexible B*and C* calculator that also calculates F0 values for UHT-treated milk. The calculator allows users to set time intervals in either seconds or minutes at predetermined temperatures. This calculator along with the other two thermal processing calculators should enable the  lethal effects of most thermal processes to be evaluated. The calculator is at www.dairyscience.info/uht1.asp .
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Admin Quote  Post ReplyReply Direct Link To This Post Posted: 13 Nov 2011 at 9:29pm
Welcome back, and thanks for the suggestion.
Prior to Ryan's post I would not have anticipated anyone wanting this sort of calculator. I will think about your request and let you know what I decide. I suppose I wonder just how much use this calculator would be?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mstrange Quote  Post ReplyReply Direct Link To This Post Posted: 12 Nov 2011 at 11:23pm
Could you change your C* calculator to allow cals of a few  holding times eg 3 min at say 123 C and say 10 secs at 90C?
 
This would be much used by us.
 
HugPlease!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Admin Quote  Post ReplyReply Direct Link To This Post Posted: 11 Nov 2011 at 7:42pm
Ryan
 
Apologies. I misread your post, you wrote 125 not 121C. Please replace the 121 with 125. Sorry if I have confused you.
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Admin Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2011 at 9:25pm

I intend to add an article on ESL and UHT milk and will cover the calculation of C* and B* over the next month or so.

B*and C* are calculated in a similar way to F0 except that the reference temperature, z-value and the time taken to give a value of 1 are different.

B*=1 is obtained by using a z-value of 10.5 °C, a reference temperature of 135 °C and a holding time equivalent to 10.5 seconds and represents a log 9 reduction in thermophilic spores.

The C* value measures the chemical effect of high temperature processing and is concerned with thiamine destruction. A reference temperature of 135 °C, a Z-value of 31.4 °C and a holding time of 30.5 seconds are required to give a C*=1; this corresponds to a 3 % reduction in the thiamine concentration in the food being processed.

I think you want to calculate the B* and C* values resulting from heating a food in a retort at 121°C for 7 minutes? B* and C* values are normally used for UHT processing and I don’t understand why you are using them for a product produced at a much lower temperature.

To calculate B* enter the following into Excel:

=10^((121-135)/10.5)*7*60/10.1. Note the 7 minutes have been converted to seconds.

To calculate C* enter the following into Excel:

=10^((121-135)/31.4)*420/30.5.

I have not checked these calculations but they should work fine. Expect to see C* higher than B*! If you are doing this calculation as an assignment you will need to explain why this has occurred, in UHT processing the C* value is always less than the B* value!
Finally can you say why you are doing this calculation; I can understand why you have calculated C*?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ryan Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2011 at 6:55am
I'm sorry Mr Michael


I Want to ask how to calculate B* and C* if i used retort
what formula should i used
my product is dairy, and my parameter retort is 125 C & 7 menit

Thank you for your attention
I'm very need your help
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Admin Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov 2011 at 9:43pm
The free On Line calculator to determine F0, B*, C* values and predicted lactulose concentrations following the UHT-treatment of milk has been added.
 
Note the B* values will usually require adjustment to allow for for the flow conditions in the heat processing plant. This usually means reducing them by a factor of 2 (Tran et al, 2008). I will add a tutorial explaining how to do this.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Admin Quote  Post ReplyReply Direct Link To This Post Posted: 26 May 2011 at 10:12pm
I will provide a spread sheet that enables Fo, B* and C* to be calculated for extended shelf life dairy products within the next few weeks.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Admin Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2011 at 8:40pm
I received the query below yesterday: "Can you please provide the calculator (Fo calculator) to calculate F0, B* and C* for ESL Dairy products. I am particularly interested in custard, stabilised thickened cream and milk".
Need much more information before I can do this? Please provide some more information. 
 
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