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Food Focus August 2008

Agricultural chemical use gets tick

Each year NZFSA develops a list of food/residue combinations and then tests them for chemical residues. Results from the latest round of testing of New Zealand’s fresh, unwashed produce have given a tick to the industry

The Food Residue Surveillance Programme (FRSP) is one of a suite of ongoing monitoring programmes NZFSA carries out. The combined surveys give a picture of what chemicals New Zealanders are exposed to through their food.

The aim of the FRSP is to assess how effective our controls are around agricultural chemical use by testing for chemical residues on crops. It is carried out each year and is timed to gather fresh produce during normal harvest cycles. Between four and eight types of produce are targeted, with the choice of crop determined by a range of factors.

NZFSA Principal Advisor (Chemicals), Dr Paul Dansted says: “Because the FRSP sets out to probe specific foods, for example those that may be problematic because they are susceptible to attack by pests or disease, it is more likely to identify problems than a purely random survey chosen from all foods. Only when such problems are identified can they be dealt with by education, regulation, sanctions or even legal action in extreme circumstances. In some cases a combination of these may be required.”

Choosing which produce to test

The range of produce available in New Zealand is so large only a small sample can feasibly be tested each year. The foods chosen are often varieties that authorities overseas have found to contain higher residue levels, or minor crops where growers may not have access to specific information about use of a particular agricultural compound on that crop.

NZFSA draws up a list of most likely candidates and prioritises it against certain criteria, such as:

• available information about use and residues of agricultural compounds

• previous domestic surveys, known data gaps, or stakeholder interest

• overseas intelligence and the likelihood of similar practices here or of foods being imported

• dietary intake-related factors, such as chronic and acute toxicity of the chemicals, residue levels in specific foods and consumption patterns

• availability of cost-effective laboratory analyses for the residues of interest

• integrity of the food-supply chain.

This year capsicum, strawberries, lettuce, mushrooms and courgettes were targeted from four locations (Hamilton, Hawkes Bay, Christchurch and Dunedin), over two sampling periods (December 2007 and February 2008).

How the results stack up

A total of 236 produce samples were tested, giving about 55,000 analytical results. The key results from the latest round of tests – the non-compliances – are given in Tables 1 and 2.

A dietary intake assessment of the non-compliant results showed that the residue levels did not pose a health risk to consumers as they were well below those needed to produce any human health effects. “These non-compliances make no significant difference to the amount of the chemical that New Zealand consumers are exposed to, even assuming they consumed the highest residue levels found for their entire lives”, Dr Dansted says.

Although the non-compliant samples are not a risk, Dr Dansted says work continues to reduce the number of non-compliances. The findings are used to inform growers about areas of concern and they enable NZFSA to discuss with the relevant sectors the best means of bringing the residue levels down to acceptable levels or to produce data that supports a new maximum residue level (MRL). Individual growers are told if problems are found in their crops so they can improve their practices. “If we find problem crops we follow it up in subsequent years, and if we find the problem again with the same growers, we will take a much stronger regulatory approach”, he says. “We are generally pleased with the result of this survey, but we fully expect, from time-to-time, to uncover problems that require corrective action.”

The FRSP results can be found here.

Maximum residue levels

The MRL is the highest concentration of residue allowed in food crops or animal products at harvest or sale. It is legally enforceable, which means growers and other suppliers must not sell produce that exceeds a given MRL and non-compliances must be addressed.

The MRL is set so that at harvest the chemical will have done its job and the resulting residue is as low as possible. MRLs are not safety limits, although they are set below levels which are known to have any adverse health effect. They also take into account how much of each food people are likely to eat, ie dietary intake.

Table 1: FRSP 2007–08 results for season 1

Produce	No. of samples taken	Chemical	No. of non-complying samples	Non-compliance (mg/kg)	Maximum residue level (NZ)
Capsicum	24	Iprodione	1	0.12	0.1mg/kg
		Propham	1	0.11	0.1mg/kg
		Methamidophos	1	0.39	0.2mg/kg
Courgettes	24		none
Lettuce	24	Permethrin	2	0.21/0.30	0.1mg/kg
Mushrooms	24	Prochloraz	2	1.1	0.5mg/kg
Strawberries	36	Cyprodinil	2	0.12/0.13	0.1mg/kg
		Fludioxinill	2	0.11/0.12	0.1mg/kg

Table 2: FRSP 2007–08 results for season 2

Produce	No. of samples taken	Chemical	No. of non-complying samples	Non-compliance (mg/kg)	Maximum residue level (NZ)
Capsicum	24	Iprodione	1	0.12	0.1mg/kg
Courgettes	24		none
Lettuce	24	Acephate	1	6.4	6.0mg/kg
Mushrooms	24	Prochloraz	1	0.71	0.5mg/kg
Strawberries	12		none

Foods surveyed for the FRSP 2003–2008

apricots	green beans	pork
bananas	lettuce	potatoes
broccoli	mandarins	prawns
cabbages	mushrooms	pumpkins
carrots	onions	raspberries
cauliflower	oranges	scallops
celery	oysters	spinach
courgettes	peaches	strawberries
crabs	peanuts	taro
cucumbers	pears	tomatoes
fancy lettuce	peppers	wheat
grapes	plums	wine