Excessive pesticides found in bok choy, twice

Food safety officials say bok choy growers who used chemical sprays at too high a level in two consecutive pesticide residue surveys were not told of the problem until after the second round of surveys.
``Samples for the two rounds were taken so close together that growers didn't have time to change their practices based on our investigators' visits and the information we have given them,'' said Food Safety Authority (NZFSA) principal adviser for chemicals, Paul Dansted.
An initial study in February by the NZFSA residue surveillance programme found concerning levels of chemical residues in bok choy with 10 out of 23 samples containing levels of the fungicide chlorothalonil or the insecticide thiamethoxam over the allowable limit.
But growers were not told of the survey results until July, and in the meantime, a further survey in April found 11 cases of chemicals over the allowed maximum residue level found in the 23 samples taken. The second round results released today were almost a carbon copy of what was found in round one.
Dr Dansted told NZPA that growers had treated the bok choy as a brassica when applying chemicals, but it should have been sprayed as though it absorbed and retained residues as a ``leafy vegetable''.
``Growers were not informed of the misinterpretation of the crop grouping before the second round of samples had been taken,'' he told NZPA .
The maximum residue levels (MRLs) were often set at different levels for leafy vegetables and for brassicas.
Such breaches did not mean the food was unsafe, said Dr Dansted: ``MRLs are set at a level that will ensure a person's total exposure to that chemical will be within the acceptable daily intake.''
Using an agricultural chemical on different crops was not specifically restricted unless it had been banned or had a registration condition stating label directions must be followed.
``It is feasible that a grower could continue to use the chemical on their crops but adjust the period they spray before harvest to take into account the requirement to comply with a lower residue limit,'' he said.
Green Party food safety spokeswoman Sue Kedgley said today she was also concerned that half of the samples of bok choy the authority had tested contained illegally high levels of pesticides.
``When over half the samples are turning up high percentages of illegal pesticides, the NZFSA should be concerned, rather than claiming everything is hunky dory,'' she said.
The NZFSA programme targeted locally-produced and imported crops to check whether growers had followed good agricultural practices.
Excessive levels of a fungicide, metalaxyl, and an insecticide, methamidophos, were also found in six samples of New Zealand cucumbers at non-compliant levels, and trace levels of a banned pesticide, endosulfan.
``Our investigators will be visiting the errant growers to ensure they know how to keep good records of chemical use and understand how crops are classified,'' Dr Dansted said.