SQF 2.5.4.2 Lab proficiency testing

2.5.4.2:

On-site personnel that conduct environmental or product testing shall participate in an applicable proficiency testing program at least annually to ensure accuracy of results.

We do not conduct pathogen testing at our facility. We only conduct APC and YM for finished products and APC, YM, and EB for environmental zone 1 swabs.

Would we need to participate in an expensive accredited proficiency testing program for these tests? Would we be able to make our own proficiency test with our external accredited lab where we test the same sample as the lab and compare results?

Thank you for your help!

Do you actually carry out the testing at your facility or simply send swabs to an external lab for analysis?  If you are performing these tests in house, you can create your own proficiency testing comparing results with accredited lab results.  IMEX the lab is usually more than willing to help you with creating the proficiency testing program as well.

We carry out APC, YM and EB at our facility using 3M petrifilm plates. We are already in process of performing a "comparison" analysis with our external ISO17025 accredited lab.  We are testing the same product that they are and then are looking at the results to determine if they are within variance (i.e. statistically similar). This could be our own proficiency test, correct?

We carry out APC, YM and EB at our facility using 3M petrifilm plates. We are already in process of performing a "comparison" analysis with our external ISO17025 accredited lab.  We are testing the same product that they are and then are looking at the results to determine if they are within variance (i.e. statistically similar). This could be our own proficiency test, correct?

 You probably want to also have an observation by a supervisor or lab representative signed off for each person that performs testing to ensure that sampling technique, plating technique, and enumeration of plates is being carried out consistently/correctly by all personnel. 

These two threads are SQF specific and can provide additional information.

http://www.ifsqn.com...ing#entry119863

http://www.ifsqn.com...-sqf-ed-8-2542/

SQF supports the approach you outlined above:

11.8.1 implementation guidance

It is not necessary for the internal laboratory to be accredited to ISO 17025 or equivalent; this is required in the Code for only external laboratories (refer to 2.5.6.1.iv); however the testing methods used must be justified and proficiency against an accredited laboratory is recommended to validate the testing methods. Laboratory waste must be labeled, stored and disposed of separately from food waste. This applies to contained waste and waste flushed to drain.

2.5.4 Implementation Guidance

If an internal or company laboratory is used, test methods should be checked against an accredited external laboratory at least once per year.

This is awesome! Thank you for your help everyone!

My next question is:  What kind of statistical analysis do I need to do to show that the external lab data and ours is comparable?

This is awesome! Thank you for your help everyone!

 

My next question is:  What kind of statistical analysis do I need to do to show that the external lab data and ours is comparable?

Look up the two methods you're comparing, determine what the 99% confidence interval for a particular result is, and see if both you and the outside lab fell within that interval.

OR

Look at how you are using the method, and determine if the variance you observed (e.g. log variance, standard deviation, whatever makes sense) would change any decisions you might make from a food safety perspective. E.g if you have false positives or negatives for pathogen testing, that's a HUGE problem. However if you're within 2 log of an APC count, and your specification limits you're checking against are up at 5 log and aren't a go/no go limit, it may not be a big deal for you.

It depends on how you plan to interpret your results what level of variation is acceptable for the safety of your product and usefulness of your in-house testing.

Risk assessment time! (IFSQN drinking game players, take a drink!)

Does this apply to lab technicians testing finished product tolerances for physical properties as well?

Yes, but it need only be similar to a CCP monitoring review

Are they performing the testing as per the SOP? and is the SOP up to date and accurate.