• Adulteration^[32]: The term refers to the intentional addition of foreign substances (e.g. cheaper oils like sunflower oil) in olive oil or the intentional mislabelling of the olive oil product, aiming to increase profit, lower production costs, or deceive consumers. The consequences of adulteration in olive oil are related to health risks and loss of consumer trust. It can lead to legal consequences for producers.
• Authentication technologies^[33]: Adulteration in olive oil is being prevented with the use of authentication technologies. These include:
• Chemical analysis/Profiling: Through a variety of testing methods, adulteration can be identified. Chemical analysis ensures that the oil product matches its specified grade (e.g. EVOO).

Image 14 – Chemical analysis of olive oil – Source: Freepik.com

• DNA barcoding: DNA samples are collected from the claimed olive variety that the oil is made of to authenticate its variety and origin.
• Electronic nose (e-nose)/Electronic tongue (e-tongue): A sensor-based technology that mimics the human sense of smell and tests to detect oxidation and rancidity in olive oil.
• Fatty acid ethyl ester: Fatty acid ethyl esters (FAEEs) in olive oil, especially in extra virgin olive oil, are recognised as quality indicators associated with fermentative processes in the olives. Elevated concentrations of FAEEs, such as ethyl palmitate, ethyl oleate, and ethyl linoleate, may suggest that the oil was made from low-quality olives or has been adulterated.
• Nuclear Magnetic Resonance (NMR) spectroscopy: A detailed analysis of the olive oil’s molecular structure, which identifies whether chemical markers have been used to adulterate it.
• Spectroscopic techniques: These detect adulteration by comparing the olive oil’s spectral properties (level of contained antioxidants and polyphenols) to established standards.
• Stable Isotope Ratio Analysis (SIRA): It measures the isotopes (e.g., oxygen) found in olive oil to trace and verify its geographic origin. It relies on the fact that each region has specific characteristics (e.g., soil composition, climate, etc.) that are shared by the olive oil produced there.
• Stigmastadienes: A test that detects bleaching during the refining process works by identifying stigmastadienes, which are formed when sterol components are exposed to high temperatures. Elevated levels of these compounds serve as a strong indicator of the presence of refined oils.
• Traceability systems^[34]: In essence, traceability systems allow the monitoring of the olive oil products during each phase. They help identify to what extent the olive oil product is authentic, safe, and in line with EU and international regulations.

Image 15 – Barcode – Source: Freepik.com

They provide access to the full circle of oil (from olive tree plantation to olive oil retail) and can include:

• ERP systems: Online computer products used in the business management of olive oil producers, and allow tracing of agricultural raw material supply, production, inventory, and logistics. This way, companies can collect real-time data regarding their activities.
• Geographic Information Systems (GIS): Grove locations and harvest zones have been mapped, allowing control over the ability to check the true origins of olive oil. They support PDO schemes as they provide cross-checked and organized information.
• Lot/Batch identification: A specific lot or batch number is assigned to each olive oil product, linking them to specific harvest dates and production, bottling, and packaging procedures.
• QR tracking: Labels with scannable codes that are linked to detailed product data (e.g., origin and variety of olives used in olive oil production).
• Traditional Specialty Guarantee (TSG): A European Union certification known as Traditional Specialty Guaranteed (TSG) emphasizes the traditional aspects of a food product, such as olive oil, in terms of its production methods, processing techniques, or composition. Unlike geographical designations, TSG certification highlights the product's traditional nature rather than its regional origin. It also protects the product name from misuse and helps consumers identify products with specific, time-honoured characteristics.
• Warehouse management systems: These are usually used by larger olive oil producers as they allow the monitoring of the transportation, storage, and distribution of olive oil.
• Quality testing methods^[35]: These are part of the authentication technologies. Not only do they certify that the olive oil product is authentic and in line with relevant regulations, but they also measure the level of quality of the product. Here are the most common and important quality testing methods of olive oil:
• Advanced testing methods: These include testing methods such as the SIRA mentioned earlier. They are performed in high-end labs or bodies responsible for olive oil certification and require advanced expertise and equipment. They are the most accurate ones in terms of results as they analyze in detail olive oil’s compounds, leaving no room for doubt as to the level of quality.
• Chemical testing methods: They are used to define the composition, purity, and oxidation state of olive oil. Through chemical procedures, they measure the oleic acid content, the freshness, the level of oxidation from UV absorption, the proportion of fatty acids, the level of sterol and wax content (frequently used in adulteration), and the level of polyphenols.

Image 16 – Chemical testing – Source: Freepik.com

• Organoleptic tests: These include the e-nose and e-tongue tests mentioned earlier. They are conducted by specialised tasting panels to determine whether the olive oil products truly fall under their given category (e.g., whether an olive oil characterised as EVOO fulfils all quality standards to be named as such).