Methods for PDO olive oils traceability: state of art and discussion about the possible contribution of strontium isotopic tool

Abstract

Olive oil represents an important ingredient in the Mediterranean diet and is appreciated both for nutritional and sensory properties, often related to geographical origin and cultivar of olive fruits employed. Fraudsters trying to seek financial gain can adulterate the product causing economic repercussions and, sometimes sanitary risks. The "protected designation of origin" (PDO) label insures a relative protection of both consumers and honest producers, since it prescribes production techniques and specific geographical origin, but one of the main problems is to set down objective tools to control these specifications. We reviewed numerous studies using various analytical tools to discriminate PDO olive oils' geographical origin depending on (1) volatiles compounds, (2) fatty acid and triacylglycerol composition, (3) trace elements, and/or (4) stable isotope ratios, but we highlighted that, despite their efficiency, none of them could provide an irrefutable identification. However, 87 Sr/ 86 Sr signature revealed to be an optimal geographical fingerprint in the same purpose for other food products like cereals, orange juice, coffee or alcoholic beverages. Such 87 Sr/ 86 Sr studies do not exist on olive oils, probably because of analytical issues, but we propose that developing complementary 87 Sr/ 86 Sr studies could be a promising tool to reenforce the characterization of PDO olive oils.

Impact of agricultural practice on the Sr isotopic composition of food products: Application to discriminate the geographic origin of olives and olive oil

“…It has been undertaken in the frame of a global approach dealing with the feasibility of a geographic identification and recognition of the origin of olive oil (Janin et al, 2014;Medini et al, 2015). The feasibility of Sr isotope measurements in oil was demonstrated by Medini et al (2015), however a better knowledge of the Sr bio-geochemical cycle during olive trees growth is now expected to consolidate the authentification of olive oil by strontium isotopic tracing.…”

Strontium carbonate precipitation as a sample preparation technique for isotope ratio analysis of Sr in mineral water and wine by quadrupole‐based inductively coupled plasma mass spectrometry

“…The identification of the origin of diverse food products has become more important in the last decade, since the declared origin of the products is seen as a quality feature and ecological footprints gain in importance. Wine and mineral water, in particular, have been investigated as well as other naturally grown food products …”

“…Commonly, fractionated ion‐exchange chromatography is utilised for this separation, employing crown ether materials such as Eichrom® Sr Spec resin (Eichrom, Lisle, IL, USA) or other selective materials such as the Empore™ Strontium Rad Disk (3 M, Minneapolis, MN, USA) or SuperLig620 and AnaLig Sr‐01 from IBC Advanced Technologies (American Fork, UT, USA). Only the first mentioned material is commonly used, however, for stable Sr isotope ratio analysis.…”

“…Wine [1][2][3][4][5] and mineral water, 6,7 in particular, have been investigated as well as other naturally grown food products. [8][9][10][11][12][13][14][15] To keep the costs for this type of analysis low, robust and already widespread analytical methods are desired, and quadrupolebased inductively coupled plasma mass spectrometry (ICP-QMS) fulfils these requirements. This instrumentation is widely available and, in addition to quantitative trace analysis, it allows the determination of isotope ratios.…”

“…Commonly, fractionated ion-exchange chromatography is utilised for this separation, employing crown ether materials such as Eichrom® Sr Spec resin [1][2][3][5][6][7][8][9][10][11][12][13][14][15]27…”