First quarter results released in September 2024
The New Zealand Total Diet Study (NZTDS) aims to evaluate the risk to New Zealanders from exposure to certain chemicals, such as agricultural chemicals, contaminants, and nutrients in a range of foods most commonly eaten in a typical diet.
The food, prepared as it would be consumed (for example, bananas are peeled, and meat is cooked), is then tested for the presence and levels of the chemicals, an estimate of exposure for certain population groups is determined, and the risk is estimated through comparison against health-based guidance values.
The first quarter of the 2024 NZTDS included sampling and testing of 73 ‘national’ foods and ingredients, bought from Auckland supermarkets from April to June 2024. This included buying at least 4 units of 2 individual brands and compositing them for testing.
We tested the composite samples for a range of agricultural chemicals, contaminants (including packaging chemicals), and nutrients.
More information on the methodology can be found in the final project outline.
2024 New Zealand Total Diet Study (Infants and Toddlers) final project outline [PDF, 2.6 MB]
What we found
We conducted a total of 44,278 chemical tests analysing 360 chemicals in a total of 940 foods and ingredients.
A general element screen was done on all foods and ingredients, including for aluminium, antimony, arsenic (total), cadmium, iodine, iron, lead, mercury, selenium, sodium, and thallium. Foods and ingredients were prioritised for agricultural chemical, contaminant (including packaging chemical), and nutrient testing.
Of the agricultural chemical tests conducted, 99.8% had levels below the limit of quantification (LOQ). Of the very small number of detections above the LOQ, none were of a food safety concern.
Of the foods tested for contaminants, 3 items were found to contain elevated levels of aluminium, which can be present in a range of products at low levels due to the use of a permitted food additive. New Zealand Food Safety has assessed the food safety risk as low because any risk can only emerge after high and consistent exposure over many years.
New Zealand Food Safety decided to include aluminium in the current study after the 2016 NZTDS identified elevated concentrations of aluminium in commercially baked goods. This was mainly due to permitted food additive 541, a raising agent called sodium aluminium phosphate (SAIP), which is used in baked products.
At the time, New Zealand Food Safety engaged with the baking industry to voluntarily phase out additive 541, and our follow-up survey in 2019 found a significant decrease in aluminium concentrations in commercial bakery goods.
New Zealand Food Safety’s 2019 exposure assessment found that the high intakes identified in the 2016 NZTDS for the younger age group had been reversed. In addition, all population cohorts had exposures of below 50% of the health-based guidance value.
This showed our engagement with industry to phase out 541 had successfully mitigated the aluminium dietary risk from commercial bakery goods identified in the 2016 NZTDS.
Given the elevated levels of aluminium found in a small number of foods in this quarter’s results, New Zealand Food Safety has decided to take a precautionary approach and is working with identified food manufacturers to phase out their use of additive 541.
In light of results from the 2016 NZTDS and the interim results from 2024, New Zealand Food Safety has also requested a review of the Australia New Zealand Food Standards Code for the additive 541.
Nutrient results were within levels that we would expect and in line with previous NZTDS findings.
Detailed results by chemical groupings
- Agricultural chemicals 1 [XLSX, 5.3 MB]
Includes: a multi-residue screen covering a wide range of insecticides, fungicides, herbicides and chemical groups such as organophosphates, organochlorines, triazoles, and neonicotinoids. - Agricultural chemicals 2 [XLSX, 243 KB]
Includes: a targeted multi-residue screen covering dithiocarbamate fungicides screen (expressed as CS2) and phenoxy, and aromatic acid herbicides. - Contaminants [XLSX, 210 KB]
Includes: aluminium, antimony, arsenic (total), bisphenols, cadmium, deoxynivalenol, lead, mercury (inorganic), nitrates and nitrites, phthalates, thallium, and tin. - Nutrients [XLSX, 137 KB]
Includes: iodine, iron, selenium, sodium, and zinc.
Second quarter sampling began in July 2024
The second quarter sampling round started on 22 July and will run to 30 September 2024. We will collect 43 foods across 4 regions: Auckland, Palmerston North, Christchurch, and Dunedin.
Four quarters of sampling and testing are expected to be completed by April 2025. The full report will be published mid-2026.
