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