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Do we need a metal detector in processing line of RTD Tea?

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Tran Lam Thanh

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Posted 15 January 2013 - 06:00 AM

Hi All
Do we need a metal detector in processing line of RTD Tea ? If we need the metal detector so where should it be installed in the process.
Hope to receive the explanation from you all.



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Posted 15 January 2013 - 01:49 PM

Almost certainly yes, but I am not too sure what you mean by ready to drink tea.

I have seen enormous amounts of metal dust and debris in tea. Most tea packers have in line magnets for the ferrous component and metal detectors at the end of the packing line.

The positioning and type of a metal detector depends upon your packing process and formats, but in general it should be at the last practical point before packing into secondary cases.

George @ Safefood 360°

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Posted 17 January 2013 - 04:25 PM

In line systems will reduce the frequecy of contamination before packing and some retailers will require 'end of line' detection regardless.

Mr. Incognito

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Posted 17 January 2013 - 05:18 PM

In line systems will reduce the frequecy of contamination before packing and some retailers will require 'end of line' detection regardless.

Yes sometimes it's determined by your customer rather than a standard what is required. What HACCP requires you to do is to perform a risk analysis and determine what is appropriate for your system and product based on scientific knowledge. You may not, through risk assessment, decide that you do not need a metal detector in your system.

However if your selling to a retailer that retailer may mandate something like metal detection. One previous plant I worked at we tested with metal detectors to a certain mm size. We had one customer that required we test to a size that was larger so we were already set because we tested at a smaller size. However we did have one retailer that wanted us to test to a smaller size than we already tested at. Through sharing data and collaboration we had them agree to how we already tested because the size we were looking for was already a "safe" size.

If you were to decide to put a metal detector inline with your process my suggestion would be just before it's case packed. That is how we used to test it. The product was cartoned and then it passed through a check weigher and then a metal detector on it's way to the case packer.

The only issue we had was using recycled cardboard for our cartons sometimes there would be metal pieces in the cartons. The positive side to that was we knew that they would not pass through the system. The negative side was there was a lot sometimes, not very often, where many cartons would kick off because of metal in the carton. However seeing as metal detection on the cartons was a requirement of us receiving in the cartons from our supplier the loss from that went back to our supplier.


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MD & X-ray man

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Posted 23 January 2013 - 11:07 PM


The answer to your question is not a straight forward YES or NO.

As MerleW suggested, you should do a hazard analysis / risk assessment to determine if a MD is required.

In many instances where RTD products are being made they can be run through a filter. The filter material is usually a fabric type where the holes are measured in microns. Such a filter would stop all but the tiniest particles from passing through into the final package. Importantly, such a filter would capture more metal than any MD would. So, in this example, the filter would be a better solution than the MD.

However, your customer or local regulations may require a MD regardless. In addition, there is also the problem of organic particulate matter - i.e. tea leaves that you may want to leave in the product for a more natural look, rather then having these particles removed by the filter. If this is the case then large metal pieces could potentially get through as well and thus I would suggest that a MD would be a very good idea.

If you are going to put in a MD the preferred position is on the finished items (i.e. individual RTD packages). If this is not possible then put one before this location but as close to this point as possible.

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