Food safety officials say chemical residues or contaminants found in the "average Kiwi diet" pose no safety concerns.
The New Zealand Food Safety Authority (FSA) has released the full results of the 2009 "total diet study", which tested residue levels in 123 commonly eaten foods.
It is part of a project to estimate the exposure New Zealanders get to chemical residues, contaminants and selected nutrients.
FSA project manager Cherie Flynn said the sampling did detect traces of "pesticides and other chemical contaminants".
That was because laboratory equipment was increasingly sophisticated and tests more sensitive.
"We can pick up residues at levels well below those that would have been detected in the past," she said in a statement.
More than 250,000 analyses had been carried out on food samples.
"There have been a very small number of issues that required further investigation, and none of those posed a health risk to consumers," she said.
Growers and manufacturers were reminded of the need to follow good agricultural and manufacturing practices.
The most commonly found agricultural residue was piperonyl-butoxide, a chemical added to insecticides to boost their effects, found in 36 samples. An organophosphate residue, pirimphos-methyl, was found in 24 samples.
Dithiocarbamate fungicide was found in 19 samples, including all four samples of a savoury infant weaning food. Arsenic was found in nine out of 12 infant weaning food samples and all 12 contained the heavy metal cadmium. Half of the infant food samples contained traces of lead.
Two brands of whole peanuts had at least 10 times as much cadmium as the other two brands tested.
Seven out of eight samples of chocolate and other sweet biscuits showed piperonyl-butoxide residues, and other traces found in similar biscuits included deltamethrin insecticide, the organophosphate insecticide diazinon, and a carcinogenic fumigant diclorvos.
Testing for agricultural residues also showed traces of cyprodnil in bran flakes, muesli, and red wine, and a DDT breakdown residue, DDE, in carbonated drinks, and icecream.
An infant-weaning food, containing custard and fruit, also had residues of diphenylamine, used in making insecticides and fungicides.
Work will now start on dietary assessments to estimate the exposure of different age and sex groups to chemical residues, contaminants and nutrients.
Because sampling for the fourth quarter of the study was carried out after it became mandatory for bakers to replace ordinary salt with iodised salt in bread, the estimates will give an early indication of whether people's iodine intake has improved.
At the same time it will measure how much salt people are getting in their food, in the wake of campaigns by the FSA and the Health Ministry to have consumers reduce the salt in their diets to combat heart and blood vessel disease.