BRC Metal Detection - Correct Placing of Test Pieces

What is the general consensus on the placing of test pieces when checking a metal detector

As close to the center of the aperture as possible ... ?

I think it depends on the type of metal detector you have so therefore, according to the manufacturers instructions

Dear Cakeman,

usually the detetectability is lowest directly in the middle of the metal detector spool. Therefore I would suggest, to place it as close to the middle as possible (during also using a product, as this is also heavily having influence on the result. if your cake is really flat, it should be placed more on the top (closer to center of metal detector). If your product is higher, it may perhaps been put into the product.

Yours

Werner

Dear Cakeman,

I think it depend on your product. Such as seafood bag, You  can put metal pieces on the top,uder product and between product.

Tina

The recommendations are that the test piece should ideally be placed as close to the centre of the aperture as possible,  This may is most likely to be in the product as the peroduct should be large enough to exceed the halfway line of the detector.  if not if may be that the aperture is too big for the product.  this means that the system has not been "optimised" and could result in a non-conformance or as has previously happened going to court and being fined.

It should be center of the apperature but most auditors like to see the test piece embedded in the bag as a piece of foreign material would be. Also taken in to consideration is the product size that you are putting through the apperature. Robert Rogers had a really good training on this for FSL 2013. If he doesn't care I will attach a few screen caps from his presentation, unless he wants to make it available himself.

Safefood 360 do a very comprehensive Whitepaper on metal detection, which I can recommend

It depends on the location of the sensor. If the sensor locates top of the product, I would suggest to place the test wands on the bottom of the aperture, since that gives the maximum signal strength.

Thanks,

Sumu 

In our spice and sugar facility, we use both methods ( top and Bottom) with the product we are going to be running.  

What is the general consensus on the placing of test pieces when checking a metal detector

Hi Cakeman,

The BRC standard is quite clear, refer to 4.10.3.5:

'The test piece shall be passed as close as possible to the centre of the metal detector aperture and .............wherever possible be carried out by inserting the test piece within a clearly identified sample pack of the food'

Regards,

Tony

just make it difficult for the head to find it, thats the point of the challenge !! :)

It depends on the product size vs. the apeture size.  The answer is actually "none of the above" because if the top of the product is the nearest place to the centre of the apeture, it should be there, if it's the centre of the product, it should be there.

Also don't forget the other axis; it should be leading edge, centre and trailing in convetional metal detection; leading and trailing for ferrous in foil.

We have one customer that wants what they call "worst case scenario"  which entails 5 passes for each test piece. 

• in front of product
• behind product
• under product
• on top of product
• in the middle of the package

Another customer wants "as close to the geometric center of the detector opening as possible"

And another that wants it in the product inside packaging. 

Find the least sensitive spot of your metal detector and pass the test piece over that line

Find the least sensitive spot of your metal detector and pass the test piece over that line

Dear Prasant,

See Posts #13, #14

Rgds / Charles.C

Ideally the test pieces should passed through the detector in the centre of the aperture of the detection head and ideally embedded in a test pack. This provides the greatest challenge to the detection system. So if it detects the wands under these conditions and in consecutive pack format then you can be confident the system is optimised for the product and process rate.

George  

Safefood 360 do a very comprehensive Whitepaper on metal detection, which I can recommend

http://safefood360.com/whitepapers/

Cazx

I go with the centre of the aperture.  We package dried fruit in 12-14kg cartons and tape the test piece to each end of the carton in line with the centre of the aperture.  I have had auditors wanting us to place in the product but when you are talking a carton line and the carton is sealed it is impractical and I have successfully argued this point  

I go with the centre of the aperture.  We package dried fruit in 12-14kg cartons and tape the test piece to each end of the carton in line with the centre of the aperture.  I have had auditors wanting us to place in the product but when you are talking a carton line and the carton is sealed it is impractical and I have successfully argued this point  

Dear relsbels,

Out of curiosity, what is yr minimum (mm SS test piece) detection level at the centre of the aperture and within a 12-14 kg carton (assuming the 2 positions are not mutually exclusive). Sounds like a significant challenge. I once audited a flour production facility who had an end of the line MD check on something like 20kg sacks. They had no idea and were equally disinclined to want to know. NC No.X (n+1). :smile:

Rgds / Charles.C

It depends on who you talk to. The manufacturer will tell you closest to the center of the aperture. Most customers want to see the package seeded with the test piece. Best practice is to place it in the package ensuring that the test piece is closets to the weakest point through the aperture, which is dead center.