US Supermarket Olive Oils – Many failed the extra virgin olive oil test, but why?
admin | July 18, 2010This report was what many in the extra virgin olive industry were waiting for. Big name supermarket olive oil brands labelled as extra virgin olive oil, randomly selected from Californian supermarket shelves, analysed by an accredited laboratory outside the US, tasted by internationally recognized taste panels, and the results reported by scientists with decades of standing in the edible fat and food industries.
You can get the report here,
http://olivecenter.ucdavis.edu/news-events/news/files/olive oil final 071410 .pdf
I’ve taken the liberty of graphically representing the data given in the report based on ‘origin’. I’ve used quotations around the word origin because when it comes to EU oils, what is on the label really doesn’t tell you very much about where the oil came from. Terms like ‘imported from Italy’ just mean that the oil was shipped from an Italian port. It doesn’t necessarily mean that it was made from Italian olives, or made in Italy. I visited the websites of the brands represented in the report, and if they made a big song and dance about being associated with Italy then I’ve put them under “Italy”. You can’t have your cake and eat it too!
If the brand was ‘generic’ or the producer was non-committal when it came to its country of origin then I’ve categorised them as ‘Mediterranean’. The US oils that were sampled were all Californian so their “country” is labeled as CA. Hell, CA’s economy is so big then it may as well be one!
Here’s what the report means to buyers of extra virgin olive oils available in Californian supermarkets..
General Quality – Acidity Level
Acidity is a general indicator of how healthy the olives were at processing and how quickly and carefully the olives were processed into oil. The lower theacidity the better.
The report showed that the extra virgin olive oils coming out of California outshone the EU oils on this very important criteria. The green arrow on the graph above shows a typical acidity for a good quality well made EVOO. With riper oils you can add up to 0.1% to this as they typically have a slightly higher FFA, but anything over 0.35 is stretching the boundaries of high quality EVOO.
All but one of the oils sampled passed the acidity test for EVOO based on the limits set down by the International Olive Council and the USDA. This wasn’t surprising as the 0.8% cut-off for EVOO is so high that just about any oil can pass. I’ve written about this in other blog entries, so I won’t go on another rant here.
How oxidised were the oils?
One of the measures of oxidation given in the report was Peroxide Value (PV). This value is particularly useful in assessing the potential for a young oil to go rancid. So the lower the value the better. However PV doesn’t do a good job in describing the oxidative state of olider oils. The following measure that is discussed (K232) strongly suggests that many of the EU oils were actually quite old at the time of testing. So I think the peroxide doesn’t tell the entire story about oil oxidation. Despite this caveat, the CA supermarket oils generally displayed a lower potential to oxidise than did the EU oils.
The Check for Old Oil – this one always gets them when it’s done!
Finally the dead give-away! A high value for the measure known as K232 is generally regarded as a good indicator that the oil contains old oil (i.e. oil from previous seasons), so clearly the lower the value of K232 the better. In the world of supermarket oils, back blending using old oil is a pretty common practice. Older oil are cheaper to buy on the bulk market and/or producers have to sell the oil that they made but couldn’t sell in a single season. Now while some brands may not be back blending, others might blend in a small proportion (less than10%) of unsold oil from the previous season, while others might be blending in 50% of three or four year old oil. The K232 measure tells us quite a lot about what is happening in the back blending rooms.
This is where many of the EU oils are caught out. Even by their own standards, a good proportion of EU oils failed this test. All the CA oils were well under the limit suggesting they were much fresher. Incidentally, EU oils tested by independent testing agencies in other countries have also found this (but haven’t published the results).
So what’s the big deal about blending back old oil? Here’s the rub:
- By definition old oil has used up quite a bit of its shelf life outside of your kitchen.
- Generally old oil has a higher acidity and therefore it will smoke at a much lower temperature, making it less useable.
- Old oil has lower health giving polyphenols as they naturally oxidise over time.
But most importantly
- Old oil doesn’t have that fresh lively vibrant wonderful olive flavour which we pay a premium for.
As a footnote, you’ll note that I’ve always referred to the oils in the report as ‘EU oils’, rather than ‘imported oils’. The reason is, that there are many extra virgin olive oils being imported into the US from outside the EU – Australia, Chile and Argentina to name a few. Some of these nations are becoming significant exporters and in general have higher expectations as to what constitutes a quality EVOO.
RG
Nicely done! Thank you for spending the time to express the findings graphically. I’m thinking about how I want to address the DAGs. Lot’s to say there!
Thank you for this clear display and explanation about the scientific backend of E.V.O.O. and helping us on our quest to educate the consumer and improve consumer and producer expectations. As an Extra Virgin producer from Chile deputing in the North American market, we are overjoyed to see quality excelling over quantity slowly but surely!
Hi Richard,
Thanks as usual for an informative post! I am guessing that some readers may have trouble downloading from the URL as it appears in this entry; folks who couldn’t get it to work should be able to download the UC Davis report testing extra-virgin olive oils at the link I just made.
Readers should really download a copy, because the report is even more useful than the blog post suggest, since it not only includes hard-to-find numbers on polyphenol content, but also Names Names for the specific tested brands. And, they bought oil at 2 or more sites for each brand, and included a range of additional, validated chemical indicators of oil quality beyond those required by IOC and USDA standards.
Hi Michael
You’re right, the report does cover a lot of ground. However I summarised just the bits I thought would make most sense to the vaguely interested readers of the blog. I also left the naming to the report. You’ll notice that I don’t mention brands in my posts as it just results in a lot of angst and dramas (particularly for someone who just puts in a bit of personal time in an effort to (hopefully) move understanding about EVOO in the right direction).
One thing that I did notice but didn’t mention in the post (as it seemed out of place), was the variablity in the chemistry of the big name brands across the different cities where the oils were sampled from. The differences in polyphenols alone tell me that within the same brand the batch variation in the oils is high. That surprises me as I would have thought that the big producers would have put a lot of effort into ensuring a consistent product in terms of style. Certainly for the few companies who I have blend for in Australia, that is their number one priority. They don’t like the idea of having a mild oil out their under their label one year and a ‘cough bomb’ out there the following year. In fact they are usually very specific about how much bitterness and pepperyness they would like to build into the blend.
RG
Hi again Richard,
Yup, I can fully appreciate that you might want to avoid drama; still, from the perspective of a consumer, it’s a lot more informative and useful to me to be able to see what specific brands did consistently well, and which poorly or poorly on some variables that are esp important to him or her (eg, I care less about organoleptics than peroxides and polyphenols). A regional analysis can help to guide one, and if we’re lucky push the Europeans to clean up their act, but it matters a lot to me that one of the California brands had polyphenol counts only in the 100-110 range, and another (with ‘virgin’ sensory rating for one bottle) was consistently in the high 300s.
On the variability: how much of this do you think might be explained by things like store turnover and packaging, rather than originating with the producer? Some brands have totally opaque lot numbers rather than proper expiry dates, and the oils at one store could have been sitting out in the store’s shelf, in the light (maybe even sunlight) for 2 y, while the product at another could be from the latest season and have just been taken out of a crate. Also, I don’t know if you know all of these brands, being in Oz, but several of the poor-performing ones have those darned clear glass bottles, so photooxidation could be a big player in PV and polyphenols, depending on time out on the shelf vs. in a cardboard box — or in an air conditioned area vs. one that is in the California heat …
Thanks again!