2 replies to this topic

[matthewcc]

Hello, I have a question that I didn't see in the forums or in the SQF GUIDANCE:

 

We are using a water activity meter to test water activity of ingredients and products.  We run calibration standards at the start of each day that we use the water activity meter to collect sample data.  The calibration standards have known water activity of 0.76 and 0.25.  Are we able to use these calibration standards to meet the SQF 2.4.4.2 requirement for proficiency testing for water activity testing?  They seem to meet the requirements (calibration, inter-laboratory comparison, for food safety, conducted for testing on-site).  However, I wasn't sure if they needed to be "unknown" or "blind" samples--the SQF guidance doesn't say.

 

We manufacture dietary supplements in the United States, are compliant with 21 CFR Parts 111 and 117, and have an SQF Edition 9 certification.  I have already read the SQF guidance for proficiency testing, and it is not clear (to me) on this subject.

 

Thank you,
Matthew

[OrRedFood]

We do a split sample and submit half to our outside lab for testing, and our technician tests the other half.  Our laboratory then looks at the results to determine if they are significantly different, and either issues a report stating they are not significantly different, or we have to investigate, correct, and resubmit.    I'm going to follow this post to see what others are doing. Thanks for posting!

[Charles.C]

Hello, I have a question that I didn't see in the forums or in the SQF GUIDANCE:

 

We are using a water activity meter to test water activity of ingredients and products.  We run calibration standards at the start of each day that we use the water activity meter to collect sample data.  The calibration standards have known water activity of 0.76 and 0.25.  Are we able to use these calibration standards to meet the SQF 2.4.4.2 requirement for proficiency testing for water activity testing?  They seem to meet the requirements (calibration, inter-laboratory comparison, for food safety, conducted for testing on-site).  However, I wasn't sure if they needed to be "unknown" or "blind" samples--the SQF guidance doesn't say.

 

We manufacture dietary supplements in the United States, are compliant with 21 CFR Parts 111 and 117, and have an SQF Edition 9 certification.  I have already read the SQF guidance for proficiency testing, and it is not clear (to me) on this subject.

 

Thank you,
Matthew

Hi mattthew,

 

IMO, in your case, the key paragraph in the Guidance is -

 

A proficiency test is a method used to demonstrate competency and validate a laboratory’s measurement process by comparing the in-house results to the results of a reference laboratory and/ or other participant laboratories.

 

 

The above is colloquially known as a ring test.

 

However, regarding the intended interpretation of "proficiency", you can also find a veritable variety of opinions in previous threads, eg -

 

https://www.ifsqn.co...ts/#entry180666

https://www.ifsqn.co...on/#entry180549

https://www.ifsqn.co...am/#entry176709

https://www.ifsqn.co...cy/#entry176376

https://www.ifsqn.co...42/#entry119382

 

Take your pick which you can eventually compare to the auditor's interpretation.

 

PS - as to the precise meaning of SQF's "applicable" and "included", Nostradamus only knows.