When you see words such as “pesticide-free”, “residue-free”, “independently tested” or “no detectable residues” on food, what do you think they mean?
Probably exactly what they sound like.
No pesticide residue was found.
But laboratory testing is more complicated than that.
A result reported as “not detected” does not necessarily mean zero. It means the laboratory did not report the substance at or above the relevant analytical limit used for that test.
And that limit can make a surprisingly large difference.
A food tested for glyphosate with a reporting or quantification limit of 0.01 mg/kg — 10 parts per billion (ppb) could come back as “not detected”.
Test the same food using a more sensitive method capable of reporting glyphosate at 0.002 mg/kg — 2 ppb and a residue may suddenly appear.
Nothing about the food has changed.
Only how closely we looked has changed.
What Does “Not Detected” Actually Mean?
Every laboratory test has limits.
Depending on the method and laboratory, you may encounter terms such as the limit of detection (LOD), limit of quantification (LOQ) or reporting limit. They are related concepts but don’t necessarily mean exactly the same thing.
The important point for consumers is much simpler.
If a laboratory reports: Glyphosate: <0.01 mg/kg
that does not establish that the food contains absolutely no glyphosate.
It tells us that glyphosate was not reported at or above 0.01 mg/kg — equivalent to 10 ppb — under that analytical method.
The actual concentration could be zero. But depending on the method and how the laboratory reports results, glyphosate could also be present below that 10 ppb threshold — at, say, 2 ppb, 5 ppb or 9 ppb — without being reported as a quantified result.
A test with a reporting limit of 10 ppb simply cannot give us the same information about those lower concentrations as a test designed to reliably report them.
Is 0.01 mg/kg A Common Glyphosate Testing Limit?
Yes.
A limit of 0.01 mg/kg is widely used in pesticide residue testing, including glyphosate testing.
One particularly useful example comes from international testing company Intertek. In its 2025 honey report, Intertek analysed 6,360 honey samples for glyphosate using LC-MS/MS. Its limit of quantification was 0.01 mg/kg.
Of those samples, 77.3% were below that limit. Around 790 organically produced honey samples were also tested using the same approach.
The number also appears throughout international pesticide regulation. In the European Union, where no specific maximum residue level has been established for a pesticide/food combination, the general default MRL is 0.01 mg/kg.
That 0.01 mg/kg figure should not be confused with a universal legal limit: MRLs differ between jurisdictions, pesticides and foods.
So testing glyphosate to 0.01 mg/kg is certainly not unusual.
But that does not make 0.01 mg/kg a dividing line between “glyphosate” and “no glyphosate”.
Nor does it mean laboratories shouldn’t look lower.
What Happens When We Test Below 0.01 mg/kg?
This is where things get interesting.
Imagine three hypothetical samples containing:
Sample A: 0.003 mg/kg — 3 ppb
Sample B: 0.006 mg/kg — 6 ppb
Sample C: 0.009 mg/kg — 9 ppb
Test all three using a method that reports glyphosate only from 0.01 mg/kg, and all three could potentially be reported:
<0.01 mg/kg
Now analyse those samples using a validated method with a reporting limit of 0.002 mg/kg.
Suddenly all three residues may be quantifiable.
The first laboratory hasn’t necessarily made a mistake.
Neither has the second.
They have simply looked to different depths.
Why Test Glyphosate Below 0.01 mg/kg?
There is an important distinction between two very different questions.
The first is:
Does this food comply with a legal Maximum Residue Limit?
If the Maximum Residue Limit is substantially higher than the laboratory’s reporting limit, testing to 0.01 mg/kg may be perfectly adequate to answer that question.
But another question is:
Is there measurable glyphosate in this food?
A more sensitive test can tell us considerably more about that.
This becomes particularly relevant when consumers are interested not simply in regulatory compliance but in whether pesticide residues are present at all.
The analytical method needs to match the question being asked.
Trace Residues Can Occur Without Deliberate Pesticide Use
There is another important part of this story.
Detecting a trace pesticide residue does not automatically establish that the producer applied that pesticide.
Residues can potentially arise through environmental contamination, neighbouring land use, spray drift, water, soil, transport or other pathways.
This is particularly relevant to organic production.
BioGro, one of New Zealand’s principal organic certifiers, describes its certification as meaning a product has met organic standards and was made without GMOs, animal testing or the routine use of synthetic pesticides.
MPI makes a similar distinction, describing “organic” as a production system and noting that organic certification standards are not food-safety standards.
That is an important distinction. Organic certification concerns how food is produced and whether it meets an organic standard. It is not the same thing as saying modern analytical equipment could never detect a trace pesticide residue in the finished food.
Organic Does Not Necessarily Mean Residue-Free
Real-world testing demonstrates why that distinction matters.
A peer-reviewed 2026 study examining glyphosate in honey, pollen and beebread used an LOQ of 0.01 mg/kg.
Glyphosate was quantified above that level in 21% of the honey samples.
Perhaps more surprisingly, 8 of the 31 honey samples certified as organically produced contained quantifiable glyphosate residues.
That does not, by itself, prove those beekeepers improperly used glyphosate.
And it does not mean organic certification is meaningless.
It demonstrates something much more fundamental:
How food is produced and what an increasingly sensitive laboratory can detect in it are not necessarily the same question.
What Does “Residue-Free” Actually Mean?
You might reasonably assume that residue-free means there are no residues.
But some residue-testing certification programmes establish compliance using defined analytical thresholds.
The Detox Project, for example, operates a CleanScan residue certification programme. Its current standard says qualifying third-party laboratories use a detection limit of 0.01 ppm — equivalent to 0.01 mg/kg or 10 ppb — or the lowest achievable LOD for a particular sample where 0.01 ppm cannot be reached.
This introduces an important distinction.
“No residue detected above 10 ppb”
is a precise analytical statement.
“Residue-free”
is how that analytical result may sometimes be communicated to consumers.
They sound remarkably similar.
Scientifically, they aren’t necessarily the same thing.
A product containing 5 ppb of a pesticide could potentially produce a “not detected” result under a method operating at a 10 ppb threshold, while another laboratory testing reliably to 2 ppb could quantify it.
Does Finding A Trace Mean The Food Is Unsafe?
No.
A laboratory detection and a health-risk assessment are different things.
Finding a residue tells us that the substance was detected and at what concentration.
It does not, by itself, establish that the concentration presents a health risk.
Likewise, detecting a pesticide residue below an applicable MRL does not establish a regulatory breach.
Maximum Residue Limits, Acceptable Daily Intakes and laboratory reporting limits all answer different questions.
That distinction matters.
It would be just as misleading to describe every trace detection as evidence that a food is unsafe as it would be to describe every result below a laboratory reporting limit as proof that the substance isn’t there.
Is More Sensitive Pesticide Testing Meaningful?
This raises an intriguing question.
As analytical technology becomes increasingly sensitive, we are able to measure substances at concentrations that would once have been invisible.
At sufficiently sensitive levels, environmental background contamination can increasingly become part of what laboratories detect.
That is a legitimate consideration when interpreting trace results.
But it doesn’t make sensitive testing meaningless.
If a laboratory has a validated method capable of reliably quantifying glyphosate at 0.002 mg/kg, then a result above that reporting limit provides information that a test with a reporting limit of 0.01 mg/kg cannot provide.
The important thing is to explain what that information means — and what it doesn’t.
Glyphosate Testing At 10 ppb Versus 2 ppb
Consider one final hypothetical example.
A food contains 5 ppb of glyphosate.
Laboratory A has a reporting limit of 10 ppb.
Result:
<10 ppb
Laboratory B has a reporting limit of 2 ppb.
Result:
5 ppb
Those results appear contradictory.
They aren’t.
Laboratory A is effectively saying:
We did not quantify glyphosate above 10 ppb.
Laboratory B is saying:
We looked further down and quantified 5 ppb.
Both statements can simultaneously be true.
What becomes much more complicated is what happens after the laboratory result leaves the laboratory.
Does <0.01 mg/kg become:
“Not detected”?
Does “not detected” become:
“Residue-free”?
Does “residue-free” become:
“Pesticide-free”?
And eventually:
“No traces of pesticides”?
At each step, a precise analytical result risks acquiring a broader meaning.
What Should Consumers Look For On “Pesticide-Free” Labels?
When you see claims such as “independently tested”, “pesticide-free”, “residue-free” or “no detectable residues”, there are several questions worth asking.
Tested for what?
A product can be independently tested for authenticity, quality, nutritional composition or microbiological contamination without necessarily being tested for pesticide residues.
What was the laboratory reporting limit?
“Not detected at 10 ppb” tells us something quite different from “not detected at 2 ppb”.
Was every batch tested?
Testing one sample periodically is different from testing every production batch.
What does “free” actually mean?
Does it mean no deliberate pesticide use? No residues above an MRL? No residues detected at 10 ppb? Or no residues detected using the most sensitive validated method reasonably available?
Those aren’t interchangeable claims.
There is another reason those distinctions matter. New Zealand’s Commerce Commission says businesses making claims about their products must have reasonable grounds for them, and recommends being specific and detailed rather than relying on vague claims.
Environmental claims must also be accurate, scientifically sound and substantiated. What that means for claims such as “pesticide-free”, “residue-free” and “no traces” deserves a closer look — and we’ll examine that separately.
Perhaps The Label Should Tell Us How Closely They Looked
There is nothing inherently suspicious about a laboratory reporting limit of 0.01 mg/kg.
It is widely used.
There is also nothing inherently unreasonable about testing below it when a validated method allows us to do so.
The problem arises when consumers aren’t told the difference.
Because a laboratory report saying:
<0.01 mg/kg
doesn’t say:
zero.
It says:
we didn’t find enough to report at this level of testing.
And when analytical science can look considerably further down, perhaps consumers deserve to know not only whether something was “independently tested” or “residue-free”.
Perhaps we should also be asking:
How hard did you look?
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.
AI is a useful creative tool for visualising complex investigative topics that cannot be meaningfully photographed, allowing us to illustrate ideas without implying that any specific scene or event actually occurred.
