Rapid Testing - Screening tool

Hey everyone 

 

Just after a bit of advice :) I had a phone call from some rep from a lab supply company (firstly he spoke to my boss who has zero knowledge on anything micro) selling rapid listeria testing, I have attached the stuff he had sent me. Its sponge swabs that are incubated for 24-30 hours and they change colour if there is listeria present. This is only a persumpitve test and is not UKAS accredited, its AOAC approved so they would then have to be sent to our outside UKAS acc lab. The only benefit i can see on this is that I can get a quicker indication if listeria is present but it seems like a waste of money, buying the swabs and incubator, as I would have to send them on to our lab to be confirmed. To me it makes no sense it seems like extra work and extra cost in the long run, to my boss he thinks this is great cause the swabs are cheaper etc. 

 

What do yous think? am I just being a negative nelly lol??

incubators insert.pdf   420.67KB   15 downloads

Insite Listeria Data Sheet.pdf   1.3MB   15 downloads

InSite.pdf   1.21MB   16 downloads

Well... for right or wrong if listeria is your only micro test, or longest micro test, for release you could run a bunch of them and have them confirmed by your lab as validation that a negative isn't a positive and then be able to send the product out quicker.  But if you find listeria through a longer method after you sent it out your going to have a recall.

 

Did you ask them why they aren't UKAS accredited yet?  Is it in process?  Were they denied?  If they haven't considered it you could tell them that if they were UKAS accredited you'd be more likely to buy and use them.

I am in agreement with you DonnaC. Rep's are always trying to push for rapid testing that don't necessarily work. I'm glad you looked at the whole process to figure out that yes in the long run it will be more money. There is a reason why these "rapid test" are AOAC approved and not UKAS accredited or vice versa.

 

Well... for right or wrong if listeria is your only micro test, or longest micro test, for release you could run a bunch of them and have them confirmed by your lab as validation that a negative isn't a positive and then be able to send the product out quicker.  But if you find listeria through a longer method after you sent it out your going to have a recall.
 
Did you ask them why they aren't UKAS accredited yet?  Is it in process?  Were they denied?  If they haven't considered it you could tell them that if they were UKAS accredited you'd be more likely to buy and use them.

 
Agree with the points above with regards to validation test. Be nice to see something new that might work??!

Dear All,

 

Do UKAS actually accredit test procedures? I thought they accredited labs and certification boards.

 

I would have thought AOAC is already at the top of the reliability tree for approved micro. methods.

 

But this does not necessarily mean that the procedure is appropriate for the current application.

 

Rgds / Charles.C

To be honest Charles I don't know all of the micro accreditation bodies.  He had mentioned that a different body was what they relied on as their standard.

Dear Donna,

 

I have fortunately never had to work with Listeria but a few comments based on MEX other rapid methods -

 

(1) ask for a copy of the aoac procedure for which the method is approved. Reps usually have them for unusually suspicious  customers. This should state any specific reservations, eg not accept open-type incubators, interference for meat-based applications. :smile: It will likely also give the ref. in J.a.O.A.C. where/when the method was justified, assuming you have the spare time to look it up. I have had bad experiences with several species/rapid methods due to undisclosed (by the rep) exceptions and brochure claims which were simply wrong.

The brochure conveniently omits any statistical info. on successful confirmations of presumptive positives, it undoubtedly exists and the omission is slightly worrying. But I tend to be suspicious by nature.

 

(2) you omitted to mention how long it takes you now to get a confirmed result ? ie how much saved time and will it make any process difference anyway? eg are all yr current routine results negative? positive? (you may vicariously enjoy being able to  cross-check yr ext.labs performance of course, at a price). I wondered if yr boss realised yr present use of ext.lab would still continue.

 

(3) no experience with the type of incubator you posted but i would definitely ask for a trial to check the stability at ca.37degC inasmuch as the listeria gadget seems to require a fairly, but not unreasonably, tight control. I presume this incubator style is cheaper than the full monty (GBP 3-400, fan assisted?)

 

@Mr.Inc - I don't know either, I thought maybe UKAS were expanding their activities, or Donna was a high-speed typist. :smile:

 

Rgds / Charles.C

Thanks All 

 

Decided not to go with them instead just changing to a more reliable lab as our other one wasn't cutting it. Told the rep this but he didn't seem to happy but sure that's life. Charles it takes us 6 days to get any kind of result back from our lab as they are hand delivered, will not send them via email as they are sent in a word doc which makes them easy to edit (cant understand why they cant scan and send as a pdf) 

 

Thanks for the advise/help it was very much appreciated :)