`Tests Find Higher Alkyl Ester Levels in Supermarket Olive Oils - Olive Oil Times

Tests Find Higher Alkyl Ester Levels in Supermarket Olive Oils

Nov. 23, 2010
Lucy Vivante

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By Lucy Vivante
Olive Oil Times Contributor | Reporting from Rome

Italy’s con­sumer weekly Il Salvagente, is report­ing the results of a study by ARPAM, the Regional Agency for the Protection of the Environment, Marche Bureau. The Ascoli Piceno based gov­ern­men­tal orga­ni­za­tion stud­ied 33 extra vir­gin olive oils from local Marche mills and 35 from super­mar­kets.

Any new analy­sis use­ful to iden­tify good qual­ity is help­ful and wel­come.- Renzo Casagrande, Colavita

The super­mar­ket olive oils showed an ele­vated level of alkyl esters, which point to an olive oil pro­duced from poor qual­ity olives. The olives could be dam­aged, over-ripe, and even fer­mented. The 33 local oils had an aver­age alkyl ester rate of 15 mil­ligrams per kilo; while the super­mar­ket oils, which were mostly EU olive oils, had an aver­age of 150 mil­ligrams per kilo. Three of the super­mar­ket oils had lev­els of 1,000 mil­ligrams per kilo, in other words, off the charts.


In November 2009, the International Olive Council decided to include this analy­sis para­me­ter in its qual­ity stan­dards used for cat­e­go­riz­ing grades of olive oil. Asked for his com­ment on the ARPAM study, Renzo Casagrande, Factory Manager of Colavita, said that Colavita has been using this IOC approved test on incom­ing olive oil since June. He added, We think that any new analy­sis use­ful to iden­tify good qual­ity is help­ful and wel­come.”

The European Community will adopt the mea­sures (a law has been drafted and is expected to pass and go into effect in early 2011) with extra vir­gin olive oil being allowed a max­i­mum of 75 mil­ligrams of alkyl esters per kilo­gram. One third of the super­mar­ket oils stud­ied by ARPAM would, under the new rules, not be con­sid­ered extra vir­gin.

Il Salvagente

Il Salvagente reports that Italian olive oil pro­duc­ers wanted more strin­gent rules (max­i­mum of 50 mil­ligrams), while Spanish pro­duc­ers wanted a higher accept­able level (100 mil­ligrams), and a com­pro­mise was reached with the 75 mil­ligram num­ber. High lev­els of alkyl esters, at least in some cases, point to a deodor­ized oil, although deodor­iz­ing oil does not lessen the pres­ence of alkyl esters.

Deodorizing, just as it sounds, removes an unpleas­ant odor from oil, and oil made from degraded olives has a bad smell. Deodorized oil mixed with a fruity oil can, at least in the­ory, pass sen­sory tests, and be sold as extra vir­gin.


Dr. Enrico Corradetti, direc­tor of the Marche lab where the study took place, told Il Salvagente that a high level of Oxyfluorfen, a chem­i­cal used to treat olives, ele­vates the alkyl esters in olive oil, and his orga­ni­za­tion will do fur­ther research on the sub­ject.

The ARPAM research found that pes­ti­cide and her­bi­cide residues were found on 85% of the super­mar­ket brands vs. 15% on the local oils. Perhaps more trou­bling was the fact that 35% of super­mar­ket oils, and 15% of local Marche oils, had residues from banned her­bi­cides and pes­ti­cides. The lab found the fol­low­ing plant treat­ment chem­i­cals: Oxyfluorfen, Metathion, Endosulfan, and Dicofol (DDT related).

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