Pesticides in fruit and vegetables

Are they harmless — or is the truth that we don’t really know?
 
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  • Updated:10 Mar 2006
 

01 .Introduction

washing tomatoes

In brief

  • There’s no convincing evidence that pesticide residues are bad for your health at the very low levels permitted in fruit, vegetables and other foods. But the research isn’t conclusive — pesticides that were once thought safe have been subsequently banned, or their use restricted.
  • You can minimise your exposure to pesticide residues by buying organic produce, peeling conventionally grown fruit before you eat it, and discarding the outer leaves of produce like lettuce.

Google ‘pesticides’ and you’ll score more than 20 million hits; do it for ‘pesticides’ and ‘cancer’ and you’ll still get about three million. Scare stories abound and when the pollsters ask consumers about food safety, pesticides often come up as a major concern.

But our food regulators assure us the levels of pesticide residues in our food are well within international safety standards, and that there are no significant risks from eating them.

At the same time, opponents of the use of pesticides are claiming they put us at risk of:

  • cancer and possibly other health problems such as
  • Parkinson’s disease and
  • impaired cognitive development in children.

Please note: this information was current as of March 2006 but is still a useful guide today.


The background

About 300 different pesticides are registered in Australia for use on fruit and vegetable crops.

  • Some are applied to crops while they’re growing
  • Others are used to protect produce after it’s harvested

Without pesticides it’s claimed crop yields would decline, costs would increase, and fruit and vegetables would end up with more grubs and mould — and it’s true that organic food (produced without the use of synthetic pesticides) is usually more expensive and crop yields are lower.

On the other hand, the overall benefits of pesticides may not be as great as their supporters would have us believe. For example, Cornell University’s Professor David Pimentel has estimated that, despite the huge amounts applied worldwide, pesticide use probably saves only around 10% of the world food supply. His calculations also suggest that the cost of the environmental and public health damage caused by pesticides exceeds their benefits.

CHOICE can’t resolve this argument, but given there’s so little certainty we did take a look at what our food regulators are doing about potential risks from pesticides.

 
 

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02.What are the risks?

 

If you’re a farmer, or you use pesticides in your garden, you’ll have seen some dire warnings on the labels. Pesticides can be distinctly nasty (some of them are based on chemical warfare agents developed during the Second World War), so it’s not surprising there’s a lot of published research on their toxicity.

  • Some experts say the research results show little or no risk,
  • others argue that pesticides are toxic even at very low levels.

The issue has become highly controversial. Passions are aroused on both sides — and it’s all too easy to selectively quote studies that support your point of view.

There’s another factor to take into account when trying to discuss pesticide use rationally: the ‘outrage effect’. Science isn’t everything when it comes to risk. To most of us (including scientists on their days off) how we rate risk also depends on various ‘outrage’ factors. For example, we’re more likely to be outraged by risks over which we have little choice or control. Skiing’s risky but fun because we choose to do it and believe we’re skilful enough to avoid accidents.

So even though in reality eating food contaminated by pesticide residues is no more risky than driving to the supermarket, we’re more concerned about the pesticides because most of us choose to go by car. And we’re exposed every day to natural toxins in foods that are a lot riskier than pesticides — potatoes, for example, can contain toxic alkaloids (especially if they’re a tad green), mushrooms contain hydrazines that can cause cancer and barbecued meat is another source of cancer-causing toxins. But these are familiar foods; we’re comfortable with the risks and there’s no outrage.

However, there are some real concerns

  • Scientific uncertainty. It’s important to remember that, while science delivers more or less reliable knowledge, there’s an element of uncertainty in all research findings. This is a particular concern in studies of pesticide toxicity because the levels allowed in foods are so small that harmful effects may not be immediately obvious. There can be a long time lag between exposure to a carcinogen, for example, and someone developing cancer (as was found with asbestos and cigarette smoke). So while the risks from pesticide residues now seem very low, there’s always the chance that pesticides currently believed to be safe may one day be revealed as hazardous. This was the case with DDT, which was once widely used as a pesticide and is now banned.
  • The cocktail effect. While most experts agree that the risk of cancer from individual pesticides is very low, others are concerned that exposure to a ‘cocktail’ of pesticides may increase the risk.

A report recently published in the UK by its Food Standards Agency upheld the scientific validity of these concerns and called for more research.

03.How well is your food tested?

 

Food standards

All foods sold in Australia must comply with the Food Standards Code, which defines maximum residue limits (MRL) for pesticides permitted in specific foods.

The MRL is determined from a number of factors including:

  • How much of the food is eaten in the average diet.
  • How toxic the pesticide is.
  • How easily the food absorbs the pesticide.

In theory, at least, foods can’t be sold if they contain pesticides that haven’t been specifically approved for that food or if the level of pesticide exceeds the MRL. But can we be sure that our food complies with the regulations?

Unfortunately how well your food’s being tested depends on where you live.

Pesticide testing varies state by state

Testing for pesticide residues is mostly left to the states. Regular testing is beyond the resources of the smaller states and territories and most of the testing that’s done by the larger states is on local produce only. Imported fruit and vegies mostly escape the net altogether (see Lax approach to imports).

  • The ACT and Tasmania do no testing at all.
  • The NSW Department of Primary Industry has a new testing program, with funding for five years, but it only looks at local produce. There’s no regular testing of produce at the point of entry or from retail outlets, so imported produce isn’t tested.
  • The NT Department of Primary Industry tests locally grown produce.
  • The Queensland Department of Primary Industry regularly tests samples from suppliers (and occasionally farmers’ markets), but does no testing of produce from retail outlets.
  • SA tested locally produced fruit and vegetables in 2003 but isn’t currently doing any testing at all.
  • Victoria regularly tests locally produced fruit and vegetables but doesn’t take samples from retail outlets.
  • The WA Department of Health has an ongoing testing program and does surveys of fruit and vegetables every two to five years. The current survey is sampling from retail outlets, including the big supermarket chains.

In the UK about 4000 food samples each year are tested, with an annual surveillance program covering dietary staples (bread, milk and potatoes) and a rolling program that tests different fruit and vegetables, cereal products and other foods every few years. (Testing is partly funded by a levy on the sales of pesticides.)

In the USA, the Food and Drug Administration regularly tests representative foods from four geographic regions of the country.

Our national regulator, Food Standards Australia New Zealand (FSANZ), has checked foods for pesticide residues in the past as part of the Australian Total Dietary Survey.

Because residues have consistently been found to be well below maximum limits, FSANZ now focuses on what it believes to be higher-risk areas, such as preservatives, but will continue to check pesticide residues from time to time.

The Commonwealth Department of Primary Industry regularly tests for pesticides as part of the National Residue Survey, but the program is aimed at foods for export and the only fruit and vegetables tested are locally produced apples, pears, blueberries and onions that are for both local and export consumption.

FreshTest

The fresh fruit and vegetable industry has its own internal testing program — called FreshTest — set up by the Australian Chamber of Fruit and Vegetable Industries.

The FreshTest program operates on a nationwide basis. Samples are collected at regular intervals from the wholesalers at central markets (such as the Flemington Markets in Sydney) and tested for a range of pesticide residues (and/or for microbial and heavy metal contamination). During 2005 the program tested 6457 samples. When problems appear there is a follow-up procedure and corrective action to ensure that it’s rectified. The Australian Chamber of Fruit and Vegetable Industries told us that over 70% of the samples tested showed no detectable residues and where residues were detected 81% were below half the MRL. Their results, though, are not generally available to consumers.

While this is an excellent scheme from the industry’s perspective, CHOICE believes that it’s no substitute for an independent testing program that’s in the public domain and fully accountable to consumers. In the UK, for example, the testing program is under the auspices of the Pesticide Residues Committee set up by the national government. This committee includes independent experts among its members and publishes Quarterly and Annual Reports which anyone can download free of charge from the Internet.

CHOICE is concerned that there’s so little independent testing for pesticide residues. Particularly for imported products it’s surely naive to believe that producers and importers will always voluntarily comply with Australia’s Food Standards Code. The rules need to be enforced.

We’d like to see regular, systematic testing on a national basis. This would avoid wasteful duplication of effort by the states and could be funded by a levy on the sale of pesticides (as in the UK).

Supermarket fruit and veg

  • WOOLWORTHS told us the majority of its fresh produce is Australian-grown and complies with FSANZ regulations. Imported items are further tested for pesticides by Woolworths Quality Assurance.
  • COLES didn’t respond to our enquiries.

04.Lax approach to imports

 
With increasing globalisation, fresh food imports are growing and we now import fresh fruit and vegetables worth more than $180 million a year.

The approach to testing local produce seems lax enough (see How well is your food tested?), but there are also concerns that imported produce, some of which comes from countries known to have a less stringent approach than Australia to the use of agricultural chemicals, may be contaminated with pesticides that either aren’t permitted here or are at unsafe levels.

Supporting this concern, surveys in the UK have found its imported food is more likely to contain detectable levels of pesticide residues than its local produce.

However, 95% of imported fruit and vegetables come into the country with no independent testing for pesticide residues.

The Australian Quarantine and Inspection Service (AQIS) is responsible for ensuring that imports comply with the Food Standards Code. A small ‘snapshot’ survey found no imports with pesticides in excess of the MRL, but AQIS normally only tests a small number of consignments, and then only for a limited range of pesticides.

05.How to avoid pesticides

 

The foods most likely to contain pesticide residues are fresh fruit and vegetables.

corn, lettuce and strawberriesOf those tested for the 2003 Australian Total Dietary Survey, the products with the highest levels were lettuce and strawberries — if pesticides worry you, it’s worth putting them at the top of your organic shopping list.

Processed foods (such as tomato purée) generally have fewer pesticide residues because a combination of washing, blanching and cooking removes the majority of pesticide residues from vegetables and fruit.

If you’re concerned about pesticide residues, don’t cut down on fruit and vegies — the risk to your health from eating less of them would far outweigh any risks posed by possible pesticide exposure. Instead:

  • Peel. Pesticides are often formulated to resist being washed off easily (so as to survive rain showers). Peeling removes residues from pesticides that stay on the surface of fruit, but you’ll be throwing away valuable nutrients in the peel at the same time — the choice is yours. Some pesticides are systemic, which means they penetrate the flesh of the fruit or vegetable, so washing isn’t effective against these pesticide residues (though it’s a good idea to wash them anyway to remove dirt and potentially harmful bacteria). But it helps to throw away the outer leaves of leafy vegetables such as lettuce or cabbage.
  • Cook. Processing, including cooking, can break down some pesticide residues. Cooking can destroy some vitamins but it also improves the nutritional value of some vegetables (for example, carrots, tomatoes and sweet corn), allowing many of the nutrients to be better absorbed by your body.
  • Buy organic. While organic food can’t be guaranteed free of pesticide residues (see Go organic, below), Australian organic produce that’s been tested has been found to be either free of pesticides altogether or any residues were at very low levels.

Go organic

Organic food is grown without the use of artificial pesticides. While it’s not necessarily completely free of pesticide residues (some may have lingered in the soil from previous non-organic crops, for example), independent testing has consistently found much lower levels than in conventionally grown produce. And a recent study in the US confirmed that an organic diet there substantially reduces children’s exposure to pesticides from foods.

While there’s little evidence that organic food tastes better or is of higher nutritional value, organic farming is believed to be better for the environment than conventional agriculture.

Grow your own

Another way to be sure of just what has been added to your fruit and veg as part of the growing process is to grow your own.

If you don't have a yard large enough for fruit trees or a vegetable patch you can still grow small things such as herbs or tomatoes — even on a tiny balcony.