Choice magazine’s latest round of testing of supermarket olive oils claims that only 63% of local and imported olive oil brands can be classified as extra virgin.
The market survey testing was undertaken in July 2017. Fifty products labelled as extra virgin olive oil (EVOO) were purchased from supermarkets in South Australia. Twenty six of the products were Australian and 24 were imported.
Eighteen Australian and 15 imported brands met all test parameters for EVOO – chemistry, freshness, sensory, residues, label integrity, and true classification as EVOO under AS, EU and IOC standards.That’s 63 per cent of all imported oils tested, and 73 per cent for Australian brands.
According to Peter McFarlane from the Australian Olive Association (AOA), this is an improvement on the 2015/16 results, in which 21 per cent of imported oils and 57 per cent of Australian oils tested as EVOO.
How reliable are these test results?
But are these test results truly indicative of the quality of olive oil sold in Australia?
Let us consider the sampling strategy:
- Only fifty samples were tested – one bottle of each brand was selected. Is this a large enough sample size to provide statistically significant results?
- These samples were all purchased from South Australian supermarkets – perhaps from only one or two supermarkets. What about the rest of Australia? How do we know that these samples were representative of the rest of the Australian population of EVOO?
It would be interesting to know whether all the supermarket oils tested as EVOO when they left the producer. There are many factors that are beyond the producers’ control once the oil leaves the farm gate, and these can adversely affect the quality of the oil. Is it fair that an oil that tests as EVOO when it leaves the producer should be tested again when its quality is no longer in their control? After all, it’s the producer’s reputation that’s on the line, not the supermarket’s.
Is storage and handling part of the problem?
We know that olive oil degrades rapidly with exposure to air, heat and light. In Australia, where summer room temperatures may easily exceed 30 degrees Celsius, it is important that EVOO be stored and transported under cool conditions. A three-year study conducted between 2009 and 2012 by Australian scientists at the Australian Oils Research Laboratory in Wagga Wagga confirmed that oxygen, light and heat are indeed among extra virgin olive oil’s worst enemies.
A recent (2017) study published by Segura et al in the Journal of Food Technology showed how significantly the level of oxidation can increase after 40 weeks storage at 25 degrees Celsius. The table shows how the oxidation status (the K232 and K270 levels) of the oils increases over time for both Coratina and Arbequina extra virgin olive oils. By week 40, both oils have K232 counts that are far above the maximum for extra virgin of 2.55 absorbance units at 232nm. In a supermarket situation, if stock is not rotated properly, it’s easy to see how an oil that started out as extra virgin could fail testing if it has been stuck at the back of a shelf for more than a year.
Richard Gawel, a consultant taster and blender for a number of Australian olive oil companies and a long time appointee as Presiding Judge of most of the major olive oil shows, explains how the K232 measurement shows the oxidation level of olive oil in his blog, Slick Extra Virgin.
When oils were selected for the AOA supermarket testing, were the use-by dates checked? It would be interesting to know whether they were this season’s oils, or old stock. The report does not say.
There are further issues with stock rotation in supermarkets:
- How had the oil been stored? What stock rotation methods did the supermarkets use?
- What were the use-by dates on the oils that were tested? Were they this season’s oils, or old stock? The report does not say.
- How much control did the producers have over the quality of their oil once it left the farm?
- How were the oils transported and stored before they found their way to the supermarket shelf?
- The oils were chosen from South Australian supermarkets, but they were tested in Wagga Wagga. How were the samples transported there?
The brands that qualified as extra virgin
Barossa’s Rosedale Park Australian Ultra Premium EVOO
Cobram Estate 100% Australian EVOO – Classic Flavour (AEV Cert)
Cobram Estate 100% Australian EVOO – Light Flavour (AEV Cert)
Cobram Estate 100% Australian EVOO – Premiere (AEV Cert)
Cobram Estate Australian Ultra Premium EVOO – Picual (AEV Cert)
Coles Australian EVOO
Coles Finest Mallee Region Victoria EVOO
Foodland Australian EVOO (AEV Cert)
Francesco Adelaide Plains EVOO (AEV Cert)
Joseph 2016 First Run EVOO South Australia
Kangaroo Paw Australian EVOO (AEV Cert)
Olive Grove Australian EVOO – Mild & Fruity
Pendleton Kitchen Australian EVOO (AEV Cert)
Pinnaroo Hill South Australia EVOO Premium (AEV Cert)
Red Island Premium Australian Cold Pressed EVOO (AEC Cert)
Siena Australian EVOO
Willunga Hills Organic EVOO (NASAA Cert 5017)
Woolworths Select Australian Extra Virgin Olive Oil (AEV Certified)
Balducci EVOO (Packed in Italy)
Casa Barelli (Aldi) EVOO (AS5264-2011 Certified) (Product of Spain)
Colavita EVOO Mediterranean (Bottled in the EU)
Colavita EVOO Premium Italian (Bottled in the EU)
Coles EVOO (Product of Spain)
Dollevi EVOO (Packed in Italy)
Kirkland Signature Organic EVOO (packed in Italy)
La Espanola EVOO (Product of Spain)
Lupi Fruity Taste Cold Pressed EVOO Imported from Italy (Bottled and blended in Italy)
Macro Wholefoods Markets (Woolworths) Spanish EVOO (Australian Certified Organic)
Minerva Greek EVOO (AS5264-2011 Certified) (Product of Greece)
Minerva Kalamata Greek EVOO (AS5264-2011 Certified) (Product of Greece)
Monini Classico EVOO (Product of Italy)
Moro El Primero EVOO (product of Spain)
Woolworths Select 100% EVOO (Spanish)
About the testing
All samples were independently tested by NSW DPI Wagga Wagga, (a National Association of Testing Authorities, Australia (NATA) and American oil Chemists Society (AOCS) accredited laboratory, and International Olive Council (IOC) accredited sensory panel), for selected chemical and sensory parameters for compliance against the Australian Standard for Olive Oil and Olive-Pomace Oil AS5265-2011 (AS) , as well against the International Olive Council Trade Standard applying to olive oils and olive-pomace oils(IOC) , COI/T.15/NC No 3/Rev.11 July 2016, and EU Regulation No 1348/2013(EU) .
The results were reported to Choice by Peter McFarlane, AOA Code of Practice (OliveCare™) administrator.
Jamie Ayton, Rodney J. Mailer and Kerrie Graham. The Effect of Storage Conditions on Extra Virgin Olive Oil Quality, RIRDC Publication No. 12/024; RIRDC Project No. PRJ-002297
Segura et al. Deterioration of Extra Virgin Olive Oil Caused by Different Processes. J Food Research 6:5; 2017