Pesticide residue in fruit and vegetables

Does spending more on organic produce guarantee you'll avoid pesticide residues? We tested grapes from supermarkets, greengrocers and farmers' markets to find out.
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01 . Organic vs conventional grapes

is organic food healthier better green grapes

One reason some people are prepared to pay more for organic is to avoid pesticide residues. And when CHOICE went shopping for produce we found certified organic grapes selling for $8.98/kg, compared with $2.99/kg for grapes at Aldi. But is this price premium really worth it?

To find out, we sent nine samples of grapes from farmers' markets, supermarkets and from an organic home delivery company of Australian-grown grapes to a lab to test for 220+ pesticides.

As part of this test, we were checking to see if the grapes were below the maximum residue limits (MRL), which is the maximum legal amount of pesticide residues allowed on grapes. The MRLs are set at levels considered by the government agencies to be safe for human consumption.

The results

What our findings reveal is that for consumers, it’s impossible to tell how many pesticides are in your food and at what level.

The pesticide test found 12 different pesticides overall, all of which were below the maximum residue levels (MRL).

Unsurprisingly, the certified organic grapes from farmers’ market ($8.98/kg) and the certified organic from a home delivery box ($8.80/kg) had no detectable pesticide residues. But rather more unexpectedly, neither did the greengrocer ($2.99) sample.

At the other end of the spectrum, Aldi ($2.99/kg) and the regular grapes from the farmers’ markets ($5.99/kg) had the highest number of residues, closely followed by the supposedly “pesticide-free” sample from the farmers’ market ($6.99/kg).

The two certified organic and green grocer grapes had no detectable pesticides

The “pesticide-free” sample was interesting, because the stall-keeper at the farmers’ market was vague, bordering on evasive, when asked about the origin of the grapes and whether they were certified (they weren’t) and our shadow shopper walked away feeling unconvinced of the claims.

Factors affecting pesticide residues

The results are, of course, only a single snapshot of the fruit and veg market. The amount of residue can vary depending on the amount of pests in a growing region, farmer practice and when the grapes are exposed to the chemical – if applied before the fruit starts to develop, it usually means little residue will be present by the time the fruit matures.

The time it takes for produce to travel from farm to market also makes a difference. Most modern chemicals degrade fairly quickly in days or weeks, so fruit and veg can have higher residue levels if eaten shortly after harvest. This may account for the farmers’ market sample having higher detectable levels of pesticide residues.

To buy or not to buy organic?

If you are concerned about avoiding all pesticides, certified organic is probably your best bet. Conclusions from a systematic review published in 2012 were in line with our results. While they found that organic produce is not always more nutritious than conventional produce, it is less likely to be contaminated with pesticides and antibiotic-resistant bacteria.

Research has also shown that organic is also a farming method that focuses on being better for the environment, animal welfare and the health of farm workers. But organic produce is more expensive and is not widely available in some areas, so should you be fretting about pesticide residues if you can’t afford to buy organic?

“Australians don’t eat enough fruit and vegetables as it is,” says Tim Crowe, associate professor of nutrition at Deakin University. “If you have to make a choice, the health benefits of making sure you get your daily five serves veg and two of fruit outweigh the risks about whether or not it's organic."


 is organic healthier

* Our analysis did not include a test for sulphur, which is allowed to be used as a natural fungicide on organic grapes.


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02.Where can you find the freshest produce?



Supermarkets vs greengrocers

When it comes to sourcing the freshest and best-tasting produce, apart from other obvious signs such as over- or under-ripeness, bruising, wilting or mould, it’s pretty much pot luck with a dash of trial and error.

And you may well find fresher fruit at Coles than at the local fresh-from-the-farm market, depending on how it was farmed, picked, transported and stored. Or vice-versa.

“It’s impossible to say whether produce is fresher or better quality from a supermarket or greengrocer,” says professor Ron Wills from the University of Newcastle’s School of Environmental and Life Sciences. “It varies widely because it comes down to the efficiency of the management of each store.

"Like supermarkets, most grocers have cold-storage rooms and quality depends on how well the staff are trained to understand what should and shouldn’t be refrigerated.” Buying from central wholesale markets daily or every second day means greengrocers are less likely than supermarkets to keep large amounts of produce in storage for long periods.

And, says Colin Gray, CEO of the NSW Chamber of Fruit & Vegetable Industries, as small business owners, grocers try to differentiate from supermarkets with their wider knowledge of produce and personal service. However, the problems of slow turnover and produce quality declining while it sits on the shelf can affect both supermarkets and greengrocers.

The supply chain for supermarkets and greengrocers is similar. Produce is taken from farms by truck to a central distribution hub. For greengrocers it’s a central market in each city, and for the supermarkets it’s their own distribution hubs.

The time between paddock and plate is also similar. Bananas, for example, are typically sourced from the same region, with the smaller farmers sending produce to central markets and the supermarkets dealing directly with bigger farms.

For both, produce would be picked before being completely ripe to prevent bruising during travel. (For more on fruit transport and cold storage, check out our guide to choosing the best fruit and vegetables).

Labels will tell you the country of origin. But for Australian produce, unless there is a label showing which farm or region it's from, it’s hard to know how far it’s travelled or how long it’s been stored.

03.Are the fruits and vegetables at farmers' markets always fresher?


There’s been an explosion of farmers’ markets, from the very first in Victoria in 1999 to more than 160 across Australia today, according to the Australian Farmers’ Market Association.

True farmers’ markets have growers selling directly to customers their own produce or added-value foods such as jam or cheese that they’ve made, but not necessarily grown, from scratch.

Of all the produce outlets, you probably have the best chance of finding out the provenance of the food at a farmers’ market. The food is likely to be seasonal and picked ripe, and there are often unusual varieties not offered elsewhere.

No national accreditation

However, there is no national accreditation system for farmers’ markets, and each market has different rules about how “local” food has to be – produce isn’t necessarily direct from the farm. You really only have the vendor’s word about freshness, farming methods, how it’s been stored and how far it’s travelled.

And despite the perception that farmers’ markets offer more sustainably farmed produce, unless it is certified organic it may have been grown using the same chemicals as conventionally farmed produce, as we found in our pesticides test where the "pesticide free" grapes bought the farmers' markets were not in fact free of pesticides.

Given the potential profits to be made from premium produce, it can be tempting for stall-holders to back-fill their genuine farm produce with produce they’ve not grown themselves. But Jane Adams from the Australian Farmers’ Markets Association argues other stall-holders are pretty quick to spot irregularities.

To determine authenticity, look for certification information for organic foods and have a chat with the grower. Farmers’ market regulars we spoke to say they use their instinct to pick genuine farmers from traders who are reselling goods from a wholesale market.

04.Shopping for the most nutritious fruit and vegetables


is organic food really betterThere are a mind-boggling array of factors affecting the freshness, nutrition and taste of your food.

Most fruit and veggies are 70-90% water, and once harvested immediately start losing moisture and degrading in quality and nutritional value. So the less time between harvest and plate there is, the better.

Although time since harvest is important, there are other factors influencing quality, including the particular variety, soil health, growing methods (fertilisers high in nitrogen can reduce vitamin C levels), changes in temperature and humidity during transport, and storage methods.

As well:

  • The nutrient content and taste is optimised if produce is picked ripe.
  • Bruising leads to a loss of nutrients, so produce should be gently handled. Handpicking is less likely to damage produce than mechanical.
  • Soft or leafy fruit and veg have high levels of water-soluble C vitamins that are unstable, so the fresher they are when you eat them, the better. Shrivelling and yellowing is a sign of ageing and moisture loss.
  • Minerals and antioxidants such as carotenoids (which give tomatoes their red colour) are more stable than water-soluble vitamins, as are the nutrients in root veggies, so time since harvest is less crucial.

apples can be kept in cold storage for more than a year

Birthday apples

Birthday apple is a term for apples that are one year old before they hit the stores. Most apples are harvested between February and April, so it’s standard for them to be placed in a controlled atmosphere storage straight off the tree and distributed gradually throughout the year.

The combination of reduced oxygen levels and temperature, plus an increase in carbon dioxide, stops the apple’s production of ethylene, effectively putting it to “sleep”. Once removed from cold storage, the apples “wake up” and start ripening again.

Exact conditions in the rooms are set according to the apple variety, but incorrect storage can cause flavour loss or a brown core. Storage has little effect on apple nutrients; the way the fruit is treated before and after storage is more important.

“People may not like the idea of cold storage, but would they prefer to eat Australian apples all year or to eat imported apples?” asks Colin Gray from the NSW Chamber of Fruit & Vegetable Industries.

How is early-picked fruit ripened?

In order to get fruits to market without damage, they’re usually picked before ripening, transported and then exposed to ethylene gas.

Ethylene occurs naturally in fruit and veg and naturally triggers the ripening process. Fruits such as bananas, tomatoes, avocados, apples, mangoes, pears and peaches continue to ripen after harvest as they produce their own ethylene.

There doesn’t appear to be any evidence that exposure to ethylene is harmful to crops, but if crops are picked too early they may not ripen completely. They can reach full colour, but not necessarily full nutrition.

Other fruit such as raspberries, cherries, grapes, lemons, oranges, pineapples and strawberries don’t ripen after harvest, but oranges and lemons can be made to look less green by exposure to ethylene gas.

With a structure similar to ethylene, 1-methylcyclopropene (1-MCP) is used to block the fruits and veggies’ ethylene receptors, slowing the ripening. It’s used in cold storage and controlled atmosphere for tomatoes, pears, plums, avocados and kiwifruit.

05.Can you wash off pesticide residues?


is organic food really better vinePesticides are often formulated to resist being washed off easily in order to survive rain. Peeling removes residues, but the peel itself also contains valuable nutrients. Some pesticides are systemic, which means they penetrate the flesh of the fruit or vegetable.

So washing isn’t totally effective in these cases, though it’s a good idea to wash them anyway to remove dirt and potentially harmful bacteria. It also helps to throw away the outer leaves of leafy veggies such as lettuce or cabbage.

Who monitors the pesticides in your food?

While state and territory governments police the maximum residue levels (MRLs), which are the maximum levels of pesticide residues legally allowed on for fruits and veggies, there are no mandatory testing requirements and the system has been described as complicated and uncoordinated. In response, the fruit and veg industry has set up a variety of tests to monitor microbial and chemical residues in their products.

Imported foods

“There is probably a higher risk associated with foods imported from some developing countries where lack of farmer education may mean less stringent pesticide practices,” says Dr Christopher Preston, associate professor, School of Agriculture, Food & Wine at The University of Adelaide. The Australian Quarantine and Inspection Service (AQIS) tests five per cent of imported fruit and vegetables for compliance with MRLs.

Wholesale markets

The FreshTest program run by wholesale markets (which supply greengrocers) takes about 5000 samples annually from around the country. Testing for more than 100 chemicals, it reports a 95% MRL compliance rate.


Coles tests a random selection of fresh produce each month for 129 chemicals, including domestic, organic and imported produce, and says it has a failure rate of zero per cent.
Aldi outsources monthly testing, and produce suppliers are required to carry out a program of pesticide residue analysis by an independent lab.
Woolworths declined to comment.


Peak body Organic Federation of Australia says it tests five per cent of certified organic produce in the marketplace, with a 99.9% compliance rate. Australian Certified Organic randomly tests domestic and imported organic products. It has conducted 100 tests in the past six months, screening for 50 chemicals with a reported 99% free of any chemicals and one per cent with pesticide residues with levels that are legal for conventional food.

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