No concerns over chemical residues in food

New Zealand consumers have no need to worry about chemical residues in their diet, further test results from the New Zealand Food Safety Authority (NZFSA) show.

NZFSA today released the second quarter results for the Total Diet Study (TDS). The five-yearly study puts more than 120 commonly eaten foods into the lab to assess New Zealanders’ dietary exposure to residues of chemical residues, contaminants and selected nutrients.

“Now that we have looked at all the 123 foods we will be sampling in this year’s study, it reinforces initial indications that the average New Zealand diet poses no health concerns from chemical residues,” project manager Cherie Flynn says.

The second quarter of the study looked at 62 nationally available foods that were prepared for eating – for example meat cooked and bananas peeled – before being tested. Of more than 60,000 analyses, only two areas will be investigated further.

One was a non-compliant tomatoes-in-juice product made from New Zealand and Italian tomatoes, which had residues of the insecticide methamidophos slightly above the maximum residue limit of 0.1mg/kg.

The other was higher than expected levels of lead in domestically produced bran flakes. Cherie Flynn says the products in question don’t pose any health concerns. “Even if the bran cereal was the only cereal a person was eating it would only amount to between three and 12% of the provisionally tolerable weekly intake for lead.”

However, as higher than expected lead levels were found in breads in the first quarter and in bran flakes this time, Cherie Flynn says it is an area that will be further investigated. “Because lead was detected in two grain-based products, we will be including wheat in the Food Residues Surveillance Programme (FRSP) that we carry out towards the end of this year.” The FRSP is an annual study that assesses the effectiveness of chemical residue controls on imported and locally-produced foods.

NZFSA has notified the manufacturers of the bran flakes products and the tomatoes-in-juice so they can check their quality controls.

As with the first quarter results, fish and seafood showed the expected higher levels of arsenic and mercury than other categories of food. Cherie Flynn says this is because some species of fish are inherently higher in those compounds because of their long life and diet. “Even at the levels we have detected, these foods would pose no health concerns.” The results for arsenic and mercury are comparable to what was found in the last TDS.

Of the foods sampled for the second quarter, Cherie Flynn says it is pleasing to see that none had residues of the now banned insecticide endosulfan. “From the sampling that we are doing, it appears that endosulfan is not being used in New Zealand since ERMA New Zealand prohibited its use in January.”

The 2009 Total Diet Study second quarter results are available on our website:

2009 New Zealand Total Diet Study

Note to the editor:

Care needs to be taken when interpreting results for arsenic and mercury in food. To reduce costs and allow for more samples to be analysed, standard international practice is for total arsenic and mercury to be measured and reported. However, these metallic elements are naturally found in both organic and non-organic forms and the two forms have quite different toxicities. It is the organic form that is predominant in fish. Organic mercury (methylmercury) is the most toxic of this element, which is one reason why this TDS has specifically monitored and reports both forms of mercury. It is the organic form of arsenic that is most predominant in fish (over 90%), but it is the inorganic form that is toxic. While the analysis and reporting of total arsenic does not give the true levels of its toxic form, the level of the toxic form is easily estimated from the level of total arsenic and the results provide regulators and consumers with an added safety factor.