Niki Bezzant: Should we be worried about pesticides in our food?

A Ministry for Primary Industries' study found very high levels of aluminium in muffins, cakes and slices. Photo / 123rf

Something that appears regularly in social media is scary stuff about agricultural chemical residues in our food.

It's not a new conversation. A list that crops up often (pardon the pun) is the so-called "dirty dozen" foods - the foods which reportedly contain the highest levels of nasty chemical residues.

One natural health website claims "every mouthful of non-organic food we eat is a cocktail of pesticides". Yikes.

So should we be worried about this? Are our families in danger from pesticide residue? Should we be washing all our produce? Should we buy only organic? All valid questions.

Finding out and monitoring what's going on with contaminants in our food is the job of the Ministry for Primary Industries (MPI).

It's also responsible for setting the maximum residue levels in food and making sure producers and manufacturers stick to good practice.

Every five years or so, the Ministry conducts its NZ Total Diet Study to assess our exposure to chemical residues, contaminants and selected nutrients from foods in the average Kiwi diet. The last study results were released last week.

MPI looked at about 130 of the most common foods in our diets, analysing 1056 food samples for 301 agricultural chemicals and 10 elements, including known contaminants such as arsenic and mercury.

They combined these results with food consumption data for 10 different groups in the population, to come up with estimated exposures to all of these chemicals; in other words how much we're likely to consume of each thing.

The results are interesting. MPI says they show the food Kiwis eat has a "high level of safety in regard to chemical hazards".

All of the exposures to agricultural chemicals studied were well below its Health-Based Guidance Values.

Many were far below 1 per cent of these values.

Our exposure to many contaminants seems to be trending down. We're exposed to 30 to 40 per cent less lead than in 2009, and DDT (an organic pollutant) is now almost undetectable. It's still present in tiny amounts in meat; hanging around in soil even though it was banned in the 1980s.

There were some unexpected results: very high levels of aluminium in muffins, cakes and slices, for example, putting teenage girls' exposure to aluminium over the recommended level.

This is thought to be from the flour used to bake them, which likely contains an aluminium-based raising agent.

So what about that dirty dozen list of dangerously chemical-laden produce? It turns out this is a list prepared by American organisation the Environmental Working Group, based on analysis of the US food supply.

It's irrelevant for New Zealand, and even if we did have a list like this, we'd need to also understand the difference between residues being detected in foods, and our actual risk of harm from those residues.

Here, the most dangerous chemical in our diet is one we consume willingly: sodium (salt). This study shows despite health warnings, we still have too much.

• Niki Bezzant is editor-at-large for Healthy Food Guide. healthyfood.co.nz.