Quality Management 15
Not every olive oil shows the same quality, there are definitions of
different grades of olive oil:
1. Extra virgin olive oil – produced directly from olives only by mechanical
means without applying heat. The free fatty acid content must
be less than 0.8% and the peroxide value has to be less than 20
meq O2/kg. Furthermore must have a flawless sensory profile, i.e.
no off-flavors. Highest grade for consumption.
2. Virgin olive oil – also produced directly from olives only by mechanical
means without applying heat; acidity must be less than or equal to
2% and the peroxide value less than or equal to 20 meq O2/kg. Slight
off-flavors are allowed. This quality grade is also fit for consumption.
3. Lampant oil – low quality produced directly from olives with acidity
greater than 2% and pronounced off-flavors. Not fit for consumption.
4. Refined olive oil – produced from virgin olive oils. Via processing
(bleaching, deodorizing, etc.) unwanted substances are removed.
Taste- and odorless. Not fit for consumption.
5. Olive oil – blend of refined and native oil.
6. Raw olive pomace oil – extracted oil (hexane) from the residues of
oil production, i.e. seeds, skin and residual olive fruit pulp. Not fit
7. Refined olive pomace oil – further processed raw olive pomace oil
8. Olive pomace oil – blend of refined olive pomace oil with native olive oil
According to the Edible Oil Products Act edible oils are defined as "a food
substance, other than a dairy product, of whatever origin, source or composition
that is manufactured for human consumption wholly or in part
from a fat or oil other than that of milk." Specific regulations for vegetables
oils, like product definitions, essential composition, quality factors
and contaminants are stated in Codex Alimentarius. Depending of the
main fatty acid composition, some edible oils can be used for cooking
(e.g. sunflower oil) and/or some are considered have positive effects on
the immune and reproductive system and generally on health. Olive oil
contains mono-unsaturated fats (oleic acid 65-85%) saturated fats (palmitic
acid 7-16%) and poly-unsaturated fats (linoleic acid 4-15% and linolenic
acid 5-9%). The health benefits of olive oil are mainly attributed to
the high levels of mono-unsaturated fats and to anti-oxidant as well as
anti-inflammatory properties of minor compounds like tocopherols.
Olive oil is considered a highly valuable and healthy premium food.
On average five to ten kilogram of olives are needed to yield one liter
of olive oil. A single olive tree carries approximately 50 to 70 kilogram
of olives, depending on the variety as well as location and
climate conditions. Due to the high demand and limited production
and of course its reputation olive oil earns a premium compared
to other edible oils. Beside the positive impact on the health system,
olive oil is also enjoyed for its flavor-related characteristics and used in
many Mediterranean diets. Therefore a large and lucrative market has
formed for extra virgin olive oil.
Fraudsters take advantage of this situation and try to increase their profit
by illicit means. Thus, it is no surprise that olive oil can usually be found at the
top of many food fraud rankings. The JRC publishes monthly reports on cases
of food fraud (https://ec.europa.eu/knowledge4policy/node/35384_de)
and olive oil is mentioned regularly. The world’s production in 2019 reached
almost 3,144,000 t. The mode of adulteration can be very diverse as fraudsters
are sly and brazen at the same time. For them only the sky is the limit
when it comes to increasing profit as the following case is showing impressively.
In 2019 Europol uncovered criminal action with 20 individuals involved.
The group of criminals produced about 150 t of counterfeit extra virgin olive
oil. Their olive oil never saw a single olive! They used sunflower oil as basis and
added chlorophyll, β-carotene and soya oil. Remember, the sky is the limit.
Alone this case shows the extend to which olive oile is adulterated. Thus, it
can be expected, that the number of unreported cases and the amount of
fake olive oil flooding the market is actually much higher. The general fraudster’s
recipe for olive oil looks like this:
Take whatever plant oil + whatever chemical = superb extra
virgin olive oil
The honest usually “suffer” from a lack of fantasy to solve this equation,
luckily. Possibly slightly less brazen but still illicit is the mislabeling of the
origin. The first country that comes to one’s mind when talking about
high quality olive oil is Italy. So it is not particularly remarkable that prices
for Italian olive oil are among the highest on the market. This is why some
try to increase profit by purchasing from cheaper locations, e.g. Tunisia or
also Morocco, and subsequently mislabel it with the origin Italy. In some
cases production mode might even change miraculously from conventional
to organic production as well. Why do things by halves?
But how to detect fraudulent practices? The consumer often has hardly
any chance to uncover fraud on his own and has to rely on producers and
retailers as well as on authorities. This is exactly where the food labs enter
the plot. They accept the challenge to find analytical ways of proving if certain
statements on a label are true or belong to the realm of fantasy, thus,
providing a means to determine if a claim made on a label is true or false.
In order to achieve that, the labs use any kind of weapon from the
scientist’s armory. Quite often there is no easy way to prove adulterations,
neither for olive oil nor other food matrices. Usually, one single
method is not enough to answer all aspects and different methods and/
or technologies need to be combined.
Nowadays the choice of technology is very diverse. From classical lab
methods and photometric measurements to GC-MS, e.g. to analyze for the
content of 3-MCPD, which develops during excessive heating of olive oil,
many established methods are in use. Usually, these methods are so-called
targeted methods, which focus on a single or some few parameters that
are analyzed. But there is a hook attached to targeted analysis in the context
of food fraud: fraudsters learn how to circumvent these methods, for
example by adjusting their processing of olive oil in a way that the resulting
product is in line with the specifications for extra virgin olive oil.
In the past few years, computer processing power increased and new
analytical instruments were developed, which now provide the basis for a
new, a non-targeted, approach. Non-targeted means, that the analyst does
not focus on a single or few parameters specifically. Instead, everything that
makes it to the detector is measured, resulting in a very complex fingerprint
of a sample. Examples are High Resolution Mass Spectrometry (HRMS) and
Nuclear Magnetic Resonance Spectroscopy (NMR). While HRMS detects
everything that can be sufficiently ionized in the source (usually in the mass
range of about 100-1500 or 2000 amu), NMR (1H-NMR, to be more specific)
detects any hydrogen nuclei interaction with other atoms in a molecule.
Especially for building databases it is important to have a method
that delivers very reproducible data. NMR has proven to be a very stable
method and due to its non-target fingerprinting capability is perfectly
suited to tackle the detection of food fraud in olive oil. However, usually
a combination of a non-targeted and a targeted approach is being used
as it provides extra information to the analyst.
Fingerprinting methods rely on a database of authentic references
which are indispensable. Any new fingerprint from an unknown sample is
compared with the database fingerprints and statistically evaluated. Diverse
information can be derived from these fingerprints. For example, it is possible
to detect foreign oils, like sunflower and soya oil as mentioned in the
Europol-example above. However, statistical evaluation can also reveal the