12 replies to this topic

[psunjka]

A client of mine has been challenged by the regulatory body to explain why are they using specific relative humidity values during the drying process of dry, fermented product (sausages). They maintain the relative humidity between 50% and 90%, and the only explanation on why they use these specific values was "we know it by experience". RH lower than 50% will speed up the process and give product of a lower quality, whereas 90% will create enough moisture for microbial development. Of course, this is not good enough for the government and I need ideas how to validate the relative  humidity values during drying of fermented sausages. Any help or ideas are welcome.

 

 

[Snookie]

I may not have had enough coffee yet and brain not completely clear but are you asking how to validate that the humidity is 80% and we know this because of our meter in the room or are you looking for research that validates that this is the humidity level that should be used for the product?

[cazyncymru]

Are you just starting work Snookie? Because I'm just going home!

 

Psunjka, if your asking what I think your asking, then you would need to demonstrate (pictures , results, correlation against RH) the optimum RH for your process. Unfortunately. most people don't understand experience, but need to see something as a hard copy.

 

If your able to, and this may be difficult due to production limitations, place some sausages in at different RH and document the quality issues, micro issues etc.

Write it all up, and Voila! your validation!

 

Caz x

[Snookie]

Are you just starting work Snookie? Because I'm just going home!

 

Psunjka, if your asking what I think your asking, then you would need to demonstrate (pictures , results, correlation against RH) the optimum RH for your process. Unfortunately. most people don't understand experience, but need to see something as a hard copy.

 

If your able to, and this may be difficult due to production limitations, place some sausages in at different RH and document the quality issues, micro issues etc.

Write it all up, and Voila! your validation!

 

Caz x

Ah man....just rub in.  Yes my day is still very new and I would give a lot.....a lot to be at home right now.  Have been running on very little sleep for a couple of weeks now and am beginning to feel like road kill.    That being said, there may be research available with a bit  searching. 

Edited by Snookie, 17 July 2014 - 05:03 PM.

[jel]

It is correct that is not accepted an answer as "we know it by experience"; however they have to do is demonstrate the objective evidence of moisture levels required to achieve product safety, and that they can do even at laboratory level. 

 

In the validation of a control measure, there should be no doubt that the aim is achieved, so you must include the worst possible case. 

 

It is possible that the level of quality / safety required is not achieved only with the relative humidity, but must involve other factors, such as temperature, time, etc.., So validation should study the effect of all these factors on the product, and of course the right tool for this, is the Design of Experiments (DOE)

[psunjka]

I appreciate all valuable comments and here are some clarifications:

 

1. RH of the room, not the product moisture

2. validation of this values, not monitoring or verification

3. RH is not the only value they measure in order to control the process, Aw and pH of the product are checked regularly

 

Thanks cazyncymru for the advice, any other ideas are welcome

 

[Snookie]

There are many ways to determine the RH of the room and have included a link of one company that sells instruments of many kinds to give you this information. Some are calibrated to NIST standards which is what would be used to validate your monitoring equipment. 

 

http://www.thermowor...ducts/humidity/

[annyegu]

the site is good

[psunjka]

Snookie thanks for the link but the problem is not in validating our RH meters, but in validating process values (limits) for RH. Imagine having CCP for cooking of 74C that is used to kill Listeria/Salmonella/whatever. It's not the question of validating 74C itself, but why this value exactly. For cooking CCPs it is easy because there are regulatory requirements, but there none for RH (at least that I know of).

[MCIAN]

Hi Psunjka!

 

IMO you need to show the correlation between the 3 parameters you are monitoring, RH against pH & Aw (and micro count?).

If you can show that the pH/ Aw goes out of control with lower or higher RH, that would serve as a validation. Who knows... you might even arrive at different RH limits. Better to do this also in a separate environment - like a cabinet or hood or something - so you don't disrupt your operations.

 

Regards.

 

[Snookie]

Snookie thanks for the link but the problem is not in validating our RH meters, but in validating process values (limits) for RH. Imagine having CCP for cooking of 74C that is used to kill Listeria/Salmonella/whatever. It's not the question of validating 74C itself, but why this value exactly. For cooking CCPs it is easy because there are regulatory requirements, but there none for RH (at least that I know of).

Ahh..  I see.

 

I would agree with MCIAN that you are going to need to validate your process.  There may be some research out there, but as this is not my exact area of expertise, I did not it find during my brief research.  However, it still may be  that it still wouldn't apply exactly to their process which brings back to validating their process.  Sorry wish I could have been more help. 

[SQF1188]

If there's no regulation on RH then it's your choice on what you want the RH limits to be. All you'd have to do is validate your final product as being safe when RH falls into your specifications. Too many times regulatory agencies try to pick at something that really isn't a concern of theirs and this sort of seems like the case. If it's not a specification set by the manufacturer of your cooking equipment or a specification set by regulation, its your spec and you decide what that spec is. You may want to do a validation that has a limit for food safety as far as being over 90% saying that RH that high could cause unsafe product but being too low is a quality issue that you can specify yourself. For example, a company baking cookies may have a limit to a temperature that must reach or exceeded but they found if they had a certain humidity in their oven it made a softer cookie...all they have to do is validate their specified range of humidity as being safe through testing of final product or whatever means they find useful and there they've set their own limits and validated it as safe. Sometimes those gov't agencies dig a little too deep 

[Yoga Ramnarain]

A good understanding of the mechanism of the fermentation and drying process is required before assessing any processing parameter. In a nut shell, the bacterial fermentation process generates lactic acid which lowers the pH while a high water activity is needed to sustain bacterial growth initially. At the end of the process, a low pH and a low water activity are required to prevent bacterial growth. So the RH and its variation in the drying chamber is critical to product quality and safety.

 

The pertinent pathogenic bacteria associated with sausages must be understood and the limiting parameters of pH and water activity for microbiological control can then be addressed. Validation of the RH process can be done by

1. A scientific study already completed and can be referenced
2. Carry out an experimental study using the DOE tool referred to previously
3. Use historical records

If you have been in operation for a long period and have batch records of water activity and pH of the product in relation to the RH conditions and microbiological data, then the third option would be most suitable.