6 replies to this topic

[Ooi]

Hello, and good day! There is not any category close to “GMO contamination in food”, so I post it here, hoping to get info from anyone here having experience handling this. Firstly, on the nature of food / raw material sample that I intend to test:

It is NOT intended to contain GMO, but there is risk of it being contaminated by GMO. Purpose of test: To test the food / raw material for GMO contamination, and if present, to validate the GMO quantity against regulatory limits (for example, maximum 3 % GMO to be exempted from labelling). These limits differ from one country to another. There are lots of general information online. I would like to ask about some specifics: The right tests to choose.

 

The test strategy recommended to me by a lab is:

i. First, GMO screening for primers

(I hope I used the right terminology here, by primers I mean the p35s, FMV, tNOS, AgroBorder, etc.)

 

ii. If screening positive,

based on which of the primers is/are positive,

screen for possible, relevant event-specific identification.

 

iii. Whichever event-specific identification returns positive results, quantify it.

(My initial difficulty is with this step.) Any GMO quantification is going to return a RELATIVE result!

(So how to validate that the absolute quantity of positive GMO, say, soya or maize, do not exceed regulatory limit?)

And the step (iii.) recommended to me is,

quantify the botanical species (for example, soya or maize as a whole).

 

If species quantification results are Not Detected (<0.1%),

and since this is inclusive of GMO and non-GMO traits of the species,

we can conclude that whatever GMO that contaminates our product is insignificant despite the positive screening (results from step i.).

 

Can anyone share if you went through the same strategy above, or do you know of any faster way to achieve absolute GMO-contaminant quantification in food (i.e., that can be validated directly against regulatory limits)?

 

 

Lab accredited for absolute GMO quantification.

All labs where I live are accredited for GMO screening only (step i. above).

I contacted labs via emails (found in their website), only Eurofin and SGS replied they provide accredited GMO-quantification in food.

Do you know of any other lab accredited for GMO-contaminants quantification in food? Do share their direct contact(s).

 

 

Understanding the meaning of mLOD, pLOD, pLOQ for GMO-contaminant test in food.

On this subject, I got some explanation from labs, but I do not really understand it. I failed to find any resource online with examples specific to food products. Can anyone share some resource on this subject?

 

 

Thank you.

 

[Evans X.]

Greetings Christopher,

 

First of all I think you are going to end up with a high cost research, usually the kind done in universities. In my opinion you should go with the screening. Even if you go through all this you still won't get any closer to make a realistic quantification, cause you are going to depend on the LOQ of the laboratory.

To elaborate a bit on that the LOD is the lowest concetration of the measurand that can be detected. The LOQ is the lowest concetration of measurand that can be determined (measured). The LOD is almost always lower than the LOQ. The terms mLOD, pLOD etc propably refer to the method-LOD, practical-LOD, used in analytical chemistry to show the different factors that can affect the result.

What's more, you need to know the LOQ for GMO of the laboratory you will use for quantification. For example (crudely put) you mentioned 3% GMO can be exempted from labelling, but if the lab can only safely measure quantities that accumulate to 5%, then what will happen if you had 3.5% or 4% and the result came back as ok ? Eurofin will be ok most likely, but you still need to make sure you are on the same basis.

 

Regards,

[Ryan M.]

Good morning / afternoon / evening....

 

Usually GMO testing is not done to ensure a foodstuff is "non-GMO" or "GMO Free".  The way to establish this is through verification of supply and process with the proper paper trail behind it.  As Evans mentioned there is great limitation in the testing itself, but it is also quite costly and you will need a large amount of sampling to have anything that is "valid".

 

What is the purpose behind the testing?  What is your end goal?

[Ooi]

Good morning / afternoon / evening....

 

Usually GMO testing is not done to ensure a foodstuff is "non-GMO" or "GMO Free".  The way to establish this is through verification of supply and process with the proper paper trail behind it.  As Evans mentioned there is great limitation in the testing itself, but it is also quite costly and you will need a large amount of sampling to have anything that is "valid".

 

What is the purpose behind the testing?  What is your end goal?

 

Hi Ryan,

 

The end goal is, to answer a customer who request for "accredited test results as evidence that your product is GMO-free", but that sounds like the very task for which you said "Usually GMO testing is not done". Hehe! I think I'll need to try harder to figure out a practical solution to that request :) 

Edited by Ooi Christopher, 02 June 2021 - 03:48 PM.

[Charles.C]

Hi Ryan,

 

The end goal is, to answer a customer who request for "accredited test results as evidence that your product is GMO-free", but that sounds like the very task for which you said "Usually GMO testing is not done". Hehe! I think I'll need to try harder to figure out a practical solution to that request :) 

 

HI OC,

 

I deduce yr query is oriented to EC area. Do you know where if more specific ?

 

From (long) memory of previous forum threads on GMO topic, everything revolves around the quantitative EC definition/interpretation of "GMO-free".

 

Any meaningful answer(s) to yr primary question (ie analytical options) will probably require you to specify yr particular product/system of interest.

 

PS - PLOD and PLOQ may relate to the specific analytical procedure, eg -

 

 PLOD and PLOQ.pdf   252.74KB   11 downloads

 

MLOD looks to be more complex.

Edited by Charles.C, 02 June 2021 - 05:07 PM.
added

[Evans X.]

To put it as simple as I can the P refers to the practice while you handle the sample (eg preparation, injection etc). The M refers to the method itself, not taking into account the nature of the sample (imagine like having the perfect sample in any way imaginable and you need to see what "problems" can be caused by the method). There is also the I that refers to the Instrument used (now imagine you have the perfect sample and the perfect method and you need to see what "problems" can be caused by the equipment).

As I work in an accredited lab, you SHOULD NOT get involved with all these terms and the mathematics they involve, because first of all you just gonna get a massive headacke (same as me) and second they won't yield any practical result for you to show and trust me your customers don't actually know what either of these terms mean, even if they mention them.

So your only goal should be to get a result that shows no GMO presence or if you really want to quantify it that it is less than a specific regulation. The lab should, normally, provide you with the sampling method and size, so that it can yield a useful result for you.

 

As mentioned in post #3 by Ryan, the practical way to go is through making sure that your supply chain is clean from GMO, through analysis of their raw materials (provided by them) and even the certificates of the seeds used in the field that they are non-GMO (if they are plants in general) etc.

Edited by Evans X., 03 June 2021 - 09:22 AM.

[Ooi]

...... you SHOULD NOT get involved with all these terms and the mathematics they involve, because first of all you just gonna get a massive headacke (same as me) and second they won't yield any practical result for you to show......

 

Indeed those mathematics look interesting but a headache to study and really understand.

 

I'll attempt the more practical way like you said.