We keep hearing an argument about glyphosate testing that goes something like this:
Testing food below 0.010 mg/kg is unnecessary. Results below that level are too analytically uncertain to be meaningful. Publishing ultra-low results such as 0.002 mg/kg creates false precision and risks frightening consumers over trace amounts that may have no regulatory or health significance.
It sounds scientific.
But we recently learned something rather interesting.
The honey industry itself uses testing below 0.010 mg/kg.
And there is a very practical reason why.
Why Would A Honey Producer Test To 0.002 mg/kg?
No More Glyphosate NZ began independently testing food in June 2025.
We didn’t invent a 0.002 mg/kg testing level. We didn’t ask a laboratory to develop a more sensitive test for us. And we didn’t choose that number because it would produce more positive results.
Testing of honey for glyphosate at that level — 0.002 mg/kg, or 2 parts per billion (ppb) — was already available.
In fact, it had been available since 2024.
And we now understand, on good authority, that more than half of the honey producers using this glyphosate testing service request results down to 0.002 mg/kg.
Why?
One reason is blending.
Suppose a producer has two batches of honey.
More sensitive testing might tell them:
Batch A: 0.015 mg/kg
Batch B: 0.003 mg/kg
Now those numbers can become useful.
If the producer blended equal amounts of those two batches, the finished honey would contain approximately 0.009 mg/kg of glyphosate — below 0.010 mg/kg.
But to make that calculation, the producer needs to know more than simply that Batch B is <0.010 mg/kg. They need to know how far below.
At 0.003 mg/kg, they have a number they can work with.
And that, we understand, is one reason honey producers request testing down to 0.002 mg/kg. It gives them more information about what is happening at these very low concentrations and, where batches are blended, allows the likely concentration in the finished blend to be calculated more accurately.
There is nothing inherently improper about blending honey. It is a normal part of food production.
But there is an important point here.
Blending doesn’t remove the glyphosate. Blending a higher-residue batch with a lower-residue batch can reduce the concentration in the finished product.
In our example, the 0.015 mg/kg hasn’t somehow disappeared. Mixing it with honey containing a lower concentration has brought the concentration of the finished product down.
And that makes the value of more sensitive testing rather difficult to dismiss.
If a producer uses information showing that one batch contains 0.015 mg/kg and another 0.003 mg/kg to inform a commercial decision, those numbers clearly have practical value.
So when we hear that measurements below 0.010 mg/kg are too uncertain or misleading to be useful to consumers, we have to wonder.
The very same low-level measurements can be useful to industry precisely because they reveal what <0.010 mg/kg does not.
What Does A 0.010 mg/kg Glyphosate Reporting Limit Actually Mean?
This is where some of the discussion around glyphosate testing becomes confused.
A laboratory reporting limit is not the same thing as a safety limit.
Nor is it the same thing as a Maximum Residue Limit.
International Accreditation New Zealand provides technical guidance on measurement uncertainty, precision and limits of detection in chemical laboratories.
A test that reports results only down to 0.010 mg/kg tells us that the laboratory isn’t reporting numerical concentrations below that level using that particular test.
It does not establish that glyphosate suddenly becomes impossible to measure below 0.010 mg/kg.
More sensitive analytical methods can provide more information.
What Does Measurement Uncertainty Mean In Glyphosate Testing?
Every laboratory measurement has uncertainty.
That does not mean the measurement is meaningless. It means the laboratory recognises that an analytical result is an estimate, rather than an infinitely precise number.
Laboratories can express this as measurement uncertainty.
For example, suppose a laboratory reported a hypothetical result as:
Glyphosate: 0.0060 ± 0.0010 mg/kg (expanded uncertainty, k=2)
The 0.0060 mg/kg would be the measured concentration reported by the laboratory.
The ± 0.0010 mg/kg would be the laboratory’s stated expanded uncertainty. With a coverage factor of k = 2, this generally corresponds to approximately 95% confidence and, in this hypothetical example, an interval of approximately 0.0050 to 0.0070 mg/kg.
That is quite different from simply reporting:
<0.010 mg/kg
The < symbol means “less than”. A result reported as <0.010 mg/kg does not provide a numerical concentration below that level. From that result alone, we cannot tell whether the concentration might be 0.009 mg/kg, 0.003 mg/kg, lower still, or whether the analyte was detected at all.
A more sensitive analytical method can provide information that a <0.010 mg/kg result does not.
And measurement uncertainty does not somehow make that additional information disappear. In fact, reporting uncertainty alongside a numerical result gives the reader important information about the uncertainty associated with the measurement.
What A Glyphosate Test Result Does Not Tell Us
There is another distinction worth making.
Detecting glyphosate in a food does not, by itself, tell us that the food is unsafe.
It does not mean an applicable MRL has been exceeded.
And a laboratory reporting limit is not a health threshold.
Those are separate questions.
Our food testing asks a much simpler one:
Is glyphosate present, and if it is, what concentration does the laboratory report?
For consumers who want to minimise pesticide residues in their food, that information has value.
So Why Stop Glyphosate Testing At 0.010 mg/kg?
There may be perfectly legitimate reasons to use a 0.010 mg/kg test. Sometimes that is all the information required.
But that is very different from claiming that measurements below 0.010 mg/kg have no scientific or practical value.
The way this testing is being used within the honey industry appears to demonstrate otherwise.
If results below 0.010 mg/kg are useful enough for industry to make commercial decisions with, why shouldn’t consumers have access to that information too?
Image Source & Attribution
The feature image on this page was created using AI-assisted image generation from an original concept developed by No More Glyphosate NZ and refined for publication in Canva.
