New Zealand Total Diet Study

What is the New Zealand Total Diet Study?

The New Zealand Total Diet Study 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 determined, and the risk estimated through comparison against health-based guidance values.

The NZTDS, run every 5 to 7 years, is part of New Zealand Food Safety’s monitoring and testing programme that informs policy decision-making and food standard setting, and provides assurance on the safety of our food supply.

Total diet studies are similarly used globally to identify food safety risks.

2024 New Zealand Total Diet Study (Infants and Toddlers)

The 2024 study will focus on infants and toddlers, one of our most vulnerable population groups. Infants and toddlers are at higher risk than other population groups because of the amount of food they consume relative to their body weight, and the often more serious effects of some chemicals on, for example, brain development. In line with previous NZTDS, we are including agricultural chemicals, contaminants, and nutrients, but also some chemicals from food packaging.

Planning for the 2024 NZTDS (Infants and Toddlers) began in 2022. Food sampling and testing will run over a year from 1 April 2024 to 31 March 2025. Results of each quarterly testing round will be published throughout the course of the study. We intend to publish the final results of the study in mid-2026.

We sought your views

The proposed scope and methodology for the 2024 NZTDS (Infants and Toddlers) was released for public consultation in November 2023. All 32 submissions received by the deadline of 15 December 2023 were considered and as a result, we changed the overall methodology, including the chemicals to be analysed and the foods to be tested.

Response to submissions on the consultation – 2024 NZTDS [PDF, 2.3 MB]

Consultation on the 2024 New Zealand Total Diet Study (Infants and Toddlers)

Final project outline for the 2024 study

2024 NZTDS (Infants and Toddlers) final project outline [PDF, 2.6 MB]

Get email updates about the study

Subscribe to the Total Diet Study (Infants and Toddlers)

How we choose the foods to test for the Total Diet Study

The NZTDS tests the most commonly consumed foods in the New Zealand diet. Foods selected aim to make up about 90% of the target population's intake.

Foods are selected based on the most up-to-date food consumption information available. For the 2024 NZTDS (Infants and Toddlers), we are using data from the First Foods New Zealand and Young Foods New Zealand Studies conducted by the University of Otago.

First Foods NZ Study – University of Otago

Foods selected are categorised as either:

national foods, which are not expected to have any regional variation
regional foods, which are expected to have regional variation.

To ensure variety, foods are purchased from a range of retail outlets. National foods are purchased in one city, while regional foods are purchased from 2 North Island and 2 South Island cities.

How food is tested

Food samples are taken from a number of regions over 4 quarters of the year. Samples are prepared as they would be consumed. For example, bananas are peeled and meat is cooked. Each food is sampled twice in a calendar year to allow for seasonal variation. The sampling and analysis are managed over 4 testing periods, each lasting up to 6 weeks.

The full list of chemicals proposed to be tested is included in the consultation documentation.

Estimating our chemical and nutrient intake from food

The levels of the chemicals tested are combined with information on what people eat, for different age and gender groups, to give an estimate on the intake of these chemicals in the diet.

The level of intake of chemicals estimated for each of the groups is then compared with health-based guidance values to identify if certain chemicals are a concern in the New Zealand diet. Risks may arise from nutrient levels being too low or contaminant levels being too high.

Follow-up studies carried out after the 2016 New Zealand Total Diet Study

New Zealand Food Safety often carries out follow-up studies to look at any unusual findings from the NZTDS. These look more closely at targeted foods to check if the results we saw are outliers or part of a broader trend.

The 2016 NZTDS found the herbicide clopyralid in potatoes, kumara, and mushrooms. We did follow-up testing to see if this was an isolated event. That testing concluded the residues "may have been an incidental occurrence." You can read about the follow up survey and the findings in our report.

Clopyralid residues in potatoes, kumara, and mushrooms [PDF, 439 KB]

The 2016 NZTDS also found aluminium concentrations higher than expected in certain bakery goods, and this was identified as a potential health concern. New Zealand Food Safety engaged with industry to phase out an aluminium-containing food additive. A follow-up survey found that that use of this additive has now been phased out from use in most product recipes.

Aluminium in bakery goods [PDF, 783 KB]

Find out more

Media release about the 2016 study

Other food monitoring programmes

Results from past studies

Who to contact

If you have questions about the 2024 New Zealand Total Diet Study (Infants and Toddlers) or previous studies, email 2024NZTDS@mpi.govt.nz