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Validation of a Holding temperature calculator

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Carlos Simoes

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Posted 19 December 2021 - 06:22 PM

Hello colleagues,

Working in the food production industry (more exactly at a tomato processor) I am required to calculate the holding temperature in our aseptic filling lines. Since this is a relatively dynamic process, with variations due to raw material availability, equipment malfunctions, power outages, etc, I would like to provide my fellow workers and colleagues with a way of quickly calculating the holding temperature to be achieved at any given moment during production.

I have created a spreadsheet, and turned it into an online calculator, using GRID. What I would like would be if anyone with knowledge in this subject, could challenge the calculator and ascertain of its validity or not and/or suggest changes or corrections.

Bear in mind that in this industry we rely on sterilizing plants designed for processing products with high consistency and viscosity values, destined for subsequent aseptic filling, where the product is subject to a thermal cycle by means of indirect heat exchangers, concentric pipe type, made of four pipes having decreasing diameters and placed one inside the other. Product flows inside the central annular space, while heating or cooling fluids circulate both inside the internal and external jackets, in counter-current to the product (example CFT Olimpic TC sterilizer, designed for tomato juice, tomato pulp, tomato paste, pizza sauce, ketchup, jams and marmalades, fruit purees and concentrates, soups, baby food).

Can I have your opinion, please? The calculator is available at https://tinyurl.com/holdcalc
 



pHruit

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Posted 20 December 2021 - 08:45 AM

Do you treat the hold time/temp as a CCP?
If so, having "live" variations determined by individuals rather than the HACCP team seems potentially fraught with challenges, both in terms of any certification requirements and with regulatory requirements.

One approach I have seen used, and would generally support if implemented well, is a defined table of acceptable minimum temperatures at different flow rates - this way you can account for variations in viscosity, pump performance etc, whilst still having a very clearly defined set of critical limits. This would also mean that you could potentially program your auto-divert system (if you have one) to still work properly, as I'm not sure how you'd do that if people could change the flow rate / hold time and minimum temp requirements to suit their whims - obviously theoretically such a facility would only be used out of necessity, but I'd be a bit uncomfortable if people could randomly alter critical limits.

Could this type of approach be viable?

You could then do the validation properly with the HACCP team.



Carlos Simoes

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Posted 20 December 2021 - 12:00 PM

Do you treat the hold time/temp as a CCP?
If so, having "live" variations determined by individuals rather than the HACCP team seems potentially fraught with challenges, both in terms of any certification requirements and with regulatory requirements.

One approach I have seen used, and would generally support if implemented well, is a defined table of acceptable minimum temperatures at different flow rates - this way you can account for variations in viscosity, pump performance etc, whilst still having a very clearly defined set of critical limits. This would also mean that you could potentially program your auto-divert system (if you have one) to still work properly, as I'm not sure how you'd do that if people could change the flow rate / hold time and minimum temp requirements to suit their whims - obviously theoretically such a facility would only be used out of necessity, but I'd be a bit uncomfortable if people could randomly alter critical limits.

Could this type of approach be viable?

You could then do the validation properly with the HACCP team.

 

Thank you for your reply. Yes it is treated as a CCP. And the HACCP/Food Safety team members are the ones allowed to change the setting.

 

We are working exactly as you refereed, there is a set of tables, per type of product, with the established temperatures for different flow rates, and one of the settings is the absolute minimum temperature, corresponding to a 5-log reduction, that corresponds to the flow diversion valve automatic actioning, that i is tested every 2 hours. But that value has to be set at the same time the target temperature is set.

So, every two hours the team checks the flow rate (of course, if no intempestive changes in the operation occurs in between) and checks the divert valve (by temporarily setting its value above the current holding temperature). The "event" will be recorded in the equipment continuous log, as well as any change to the target temperature.

 

That log, along with the flow rate log, guarantees that (1), the target temperature is correctly set and maintained (2), that the divert valve set-point is correctly inserted and appropriate to the flow and (3), that the divert valve is working as intended.

 

Attached a table created by the spreadsheet version of the calculator.

Attached Files


Edited by Carlos Simoes, 20 December 2021 - 12:00 PM.




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