Measurement uncertainty interpretation

Hello,

       I hope you can help me with your knowledge. I've a doubt on how to use the measurement uncertainty in laboratory reports when I have to make a decision. Let's say the MRL for substance is 1.5 mg/kg. The lab report comes with a result of 1.7 +/- 0.3 mg/kg. 

 Can I use the measurement uncertainty to justify the use of the product since it will bring the result below the MRL but also could bring it higher?  i have seen cases where the product is accepted but I cannot find any information that confirms this. 

Forgot to add this is for the EU/UK market in case it's relevant

Thanks in advance!! 

I suspect the answer is "maybe".

Have a read of this document from DG, particularly sections E7 through E15, as this covers some of the relevant areas in terms of potential interpretation by regulatory bodies (as this is guidance only).

In practice, if challenged by the FSA, the onus would probably be on you to justify your position that the product is lawful in the UK in terms of compliance with 396/2005.

I'd suggest starting by discussing with the lab doing the analysis (I'm assuming this isn't in-house), as they should really be able to offer some advice* on their uncertainty figures, their repeatability/reproducibility, recovery rate for the analyte(s) in question etc with regard to MRL compliance.

*They probably won't call it "advice" these days though - liability concerns mean labs seem to generally not like giving anything that could be construed as advice these days, but you should hopefully be able to find a contact who can give some informal feedback on your results.

Thanks pHruit for the feedback, the document and section's you have mention are good piece of information. You assumed well and the product is not tested in-house so I will contact the laboratory. 

Do you know if similar piece of document exist for other contaminants as aflatoxins, heavy metals or shall I understand that the "Interpretation of results for enforcement purposes" is the same? 

I much appreciate your help!

I don't recall seeing an equivalent for the contaminants regs, but given the broad intent is the same - i.e. what value counts as actually exceeding a threshold in a statistically relevant sense - I would expect a very similar position.

Unless you're growing the crops yourselves, I'd also be asking your suppliers to explain how the material conforms to the MRL/contaminants requirements ;)