Kamel Ben Ammar. National Oil Office in Tunisia.

Edible vegetable oils are an integral part of the daily diet of humans. Therefore, they constitute a fundamental part of their diet that regulates human health. In particular, regular consumption of olive oil (OO) has been widely accepted as a healthy diet.

The exceptional aroma and flavor of olive oil is responsible for its recognition as a premium edible oil. Its unique composition is characterized by high levels of monounsaturated fatty acids and the presence of minor compounds with important biological properties, such as phenolic compounds. Olive oil is certainly one of the most expensive edible oils, and faced with the increase in its price in recent years, consumers have become more and more demanding about the quality and authenticity of the oil they consume. There are several international and national standards on olive oil which aim to safeguard the product and protect the consumer. The CODEX Alimentarius standard, the International Olive Council standard,and other regional and national standards define different qualities of OO,set the limits of the different parameters of oil quality and purity and propose chemical analysis methods that must be applied,including sensory analysis.

Despite the fact that the OO sector is highly regulated, olive oils, and more particularly Extra Virgin and Virgin, suffer from numerous phenomena of fraud and falsification and are among the top 5 most fraudulent food products in the world. In most cases, the fraud involves mixing EVOO with lower quality OOs such as deodorized oil, other vegetable oils, or even inedible oils, e.g. lampante oil. Additionally, the use of broad definitions for protected designation of origin (PDO) and protected gographical indiction (PGI), as well as elusive regulations regarding labeling and analytical procedures used for OO quality controland mislabeling, have led to an increase in cases of fraud. Therefore, controlling the quality and authenticity of OO is a critical factor not only from an economic point of view but also for the protection of consumers and public health.

The overall quality of OO must be determined by quality parameters, including sensory analysis, stability, nutritional value and safety (absence of contaminants, etc.). The authentic OO must comply with the producer's declaration regarding the quality of olives, natural components, absence of foreign substances, production technology, geographical and botanical origin, year of production, and genetic identity.

But the great chemical complexity of OO, its variability and the plethora of parameters affecting the composition of OO, considerably hamper the selection of absolute criteria defining quality and authenticity, and a reliable and robust methodology is not fully available.

However, technological progress has contributed greatly to the implementation of several analytical techniques, such as chromatography, to combat increasingly aggressive fraudulent attempts. But one of the most worrying fraudulent techniques is the addition of lower-quality oil or deodorized oil in extra virgin olive oil (EVOO). Ethyl Esters can give an idea of the freshness of the oil, nowadays, it seems that we have not found more reliable analytical approaches for the detection of deodorized oils; other parameters have been proposed such as diacylglycerols (DAG) and pyropheophytin (PPP), but none are used because they are not unambiguous and also change during the aging of oils. High PPP or DAG could mean the oil has been deodorized or is old or improperly stored.

The organoleptic evaluation of virgin OO by the “IOC Panel test” methodology is applied for legal purposes, in particular to classify an oil in its commercial category. To this end, the identification of the main perceived defect and the evaluation of its intensity, as well as the fruity attribute, are the main results. This method has undergone several revisions since its creation with the aim of improving its performance and reducing the differences between the different panels.

Volatile compounds, molecules that are strongly dependent on the sensory profiles of OO, can be considered as relevant quality markers. The determination of these compounds cannot in any way replace sensory analysis although it could support it, particularly in the “limit zones”,asbetween EVOO and VOO.

Mixing olive oil with other seed oils is not considered to be a fraud. In fact, practically all legislation tolerates this addition.However, the percentage of OO in the mixture must be clearly mentioned on the label. It should be noted that there is no mention of the limit values of the analytical parameters that these oils must respect to guarantee that the mixture contains the percentage of OO established in the regulations, which means that there is no analytical protocol to guarantee the percentage of OO present in the blend.

The lifespan of OO is a very important problem not only for the consumer but also for the merchant. The shelf life of OO can be described as the period of time during which, under correct storage conditions, no flavors or defects appear and all quality parameters remain within the limit established for its category. Although there are many studies describing the effects of certain environmental factors affecting OO quality, it seems that no studies are available to address the information that can be used by companies to predict shelf life.

Knowledge of the geographical origin of the oil is also important for consumers, as it fully increases their confidence. Protected Designations of Origin are considered an additional guarantee of the quality and authenticity of the oil; but we must find simple and reliable techniques to verify and guarantee the origin of the oil and its provenance.

Finally, climate change is yet another problem that increases the difficulties encountered in verifying the authenticity of OO. Indeed, quality and especially purity parameters are directly affected by changes in climatic conditions and could affect the composition of the oil. In the coming years, we may encounter OOs with compositions outside the currently standardized limits. A question then arises : Are these limits exceeded due to attempts at fraud or to a modification in the oil composition due to climate change? The answer is not obvious and easy, because it requires a lot of research work with a major objective, which is to prove the authenticity of olive oil.