For decades, the public has been reassured that pesticide residues in food are safe — not because residues are absent, but because they fall below regulatory thresholds.
The maths, we are told, has been done. The limits are conservative. The science is settled.
And yet, in February 2026, the World Health Organization and the Food and Agriculture Organization quietly issued a call for experts to re-examine the very models used to calculate dietary exposure to pesticide residues.
This was not a media moment. There was no public briefing, no consumer-facing explanation. Just a technical notice inviting specialists to help resolve unresolved questions about exposure modelling — questions serious enough to warrant an ad hoc expert meeting later this year.
For those paying attention, that alone should prompt a pause.
For readers who want to see the source material directly, the World Health Organization’s full “Call for Experts on Dietary Exposure Assessment of Pesticide Residues in Foods” is publicly available on the WHO website. It outlines the methodological questions under review and the scope of the upcoming expert meeting.
You can read the full notice here:
https://www.who.int/news-room/articles-detail/call-for-experts-on-dietary-exposure-assessment-of-pesticides-residues-in-foods
How New Zealand Uses WHO and Codex Pesticide Residue Standards
New Zealand’s pesticide residue limits do not exist in isolation. They are heavily informed by international frameworks developed through the Joint FAO/WHO Meeting on Pesticide Residues (JMPR) and adopted into global standards via the Codex Alimentarius Commission.
JMPR’s role is to evaluate pesticide residues in food and recommend “acceptable” levels — Maximum Residue Limits (MRLs) — that are then used by regulators worldwide to justify safety.
At the heart of this system are exposure models. These models attempt to answer a deceptively simple question: how much of a chemical do people actually consume through food, and is that amount safe?
But as the WHO’s own notice now acknowledges, how that question is answered is far from settled.
What WHO Is Questioning About Pesticide Exposure Models
The call for experts focuses on dietary exposure assessment methodologies — the technical frameworks used to estimate both long-term and short-term exposure to pesticide residues.
Among the issues WHO explicitly highlights:
- Whether existing models adequately address less-than-lifetime exposure
- How to assess life-stage specific vulnerability, such as pregnancy and childhood
- How different models compare in terms of conservativeness and transparency
- Whether exposure estimates reflect real-world consumption patterns
- How dissenting scientific opinions are handled and communicated
These are not minor refinements. They go to the core of how “safe” is defined.
Why Lifetime Average Exposure Models May Miss Real-World Risk
Traditionally, chronic exposure is assessed using a model known as the International Estimated Daily Intake (IEDI). It combines average food consumption data with median residue levels, then compares the result to an Acceptable Daily Intake (ADI).
On paper, this seems reasonable. In practice, it assumes that:
- exposure is evenly distributed over a lifetime,
- short-term spikes don’t matter if long-term averages remain low,
- and vulnerable life stages are sufficiently protected by population-level data.
WHO now openly questions whether that assumption holds.
The expert meeting is tasked with defining “less-than-lifetime exposure durations of toxicological concern” — an acknowledgment that what happens during specific windows of development may matter more than lifetime averages suggest.
For foods eaten daily — bread, cereals, fruit — this matters.
Why High-Consumption Diets Challenge Pesticide Safety Assumptions
To address global dietary differences, JMPR has begun trialling a newer approach: the Global Estimated Chronic Dietary Exposure (GECDE) model, including a GECDE-high scenario designed to represent higher-end consumers.
This is not accidental. It reflects growing discomfort with exposure models that smooth away risk by relying on averages.
WHO’s notice makes clear that the performance and suitability of GECDE-high is under review, particularly for assessing less-than-lifetime effects.
In plain terms: regulators are no longer confident that existing models adequately capture how real people eat, day after day.
Field Trial Data vs Food as Eaten: Why Exposure Estimates Differ
Another issue under scrutiny is how residue data itself is sourced.
Many MRLs are based on field trial data — residues measured under controlled agricultural conditions. But WHO now asks whether assessments should better incorporate monitoring data from foods as consumed.
That distinction matters.
Processing, formulation additives, and cumulative dietary patterns can all influence actual exposure. Yet these factors are often sidelined in favour of neat, standardised inputs.
The WHO’s call signals recognition that regulatory convenience may be out of step with lived exposure.
Transparency and Scientific Dissent in Codex Pesticide Reviews
Perhaps most telling is the backdrop to this review.
At its 56th session, the Codex Committee on Pesticide Residues requested additional information from JMPR, citing concerns about:
- transparency,
- conservativeness,
- and dissenting opinions within expert evaluations.
This is not a critique from outside the system. It is coming from within.
And yet, at the national level, the public message remains one of certainty: residues are within limits; therefore, they are safe.
WHO’s notice quietly contradicts that simplicity.
What WHO’s Review Means for Glyphosate Safety Claims
Glyphosate is often defended using precisely the frameworks now under review:
- ADI-based lifetime exposure calculations
- consumption assumptions that downplay daily staples
- reassurance grounded in regulatory thresholds rather than measured exposure
The WHO is not singling out glyphosate. But by questioning the models themselves, it calls into question the confidence with which safety claims are made.
If the methodology needs refining, then so do the conclusions drawn from it.
Why Pesticide Risk Modelling Matters for Public Trust
This expert meeting will take place behind closed doors. Its outputs will feed back into JMPR advice and, eventually, Codex standards.
But consumers are rarely told when the rules change — or when the science behind them is still evolving.
The problem is not uncertainty. Science evolves; that is its strength.
The problem is presenting evolving methodologies as settled reassurance.
What Happens When Pesticide Safety Models Are Still Evolving
The WHO’s call for experts does not prove harm. It does not declare current residue limits unsafe. What it does do is acknowledge that the safety maths is under review — and that important questions remain unanswered.
For New Zealanders, this matters because regulatory confidence rests on international assessments that are now being reconsidered at the highest level.
When exposure models are being re-examined, certainty should be tempered with humility. Transparency should replace reassurance. And the public deserves to know when the foundations of “safe limits” are still under construction.
At No More Glyphosate NZ, we will be watching closely — not because the science is broken, but because honest science does not pretend to be finished.
“Transparency matters. Accountability matters. And informed choice begins with understanding how decisions are made — especially when those decisions shape what ends up on our plates.”
— No More Glyphosate NZ
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