`Olive Council Chemists Issue Latest Challenge to Davis Study Claims - Olive Oil Times

Olive Council Chemists Issue Latest Challenge to Davis Study Claims

By Olive Oil Times Staff
Oct. 22, 2010 08:34 UTC


A report issued by the UC Davis lab­o­ra­tory ques­tion­ing the true­ness-to-grade of extra vir­gin olive oil imported into the United States has been pub­lished recently in var­i­ous news media. The IOC Chemistry Expert Group have dis­cussed this sub­ject at their lat­est meet­ing.

The Group is made up of expert chemists from almost all the IOC mem­ber and non-mem­ber coun­tries (Australia, Canada and the United States) and inter­na­tional organ­i­sa­tions (AOCS, CODEX and ISO). The main aim of the group is to study test­ing meth­ods and revise them when nec­es­sary to deter­mine the qual­ity and con­trol the purity of olive oils and olive-pomace oils. Methods are con­stantly being improved to adapt them to indus­try needs and tech­no­log­i­cal devel­op­ments.

IOC stan­dards are revised in the light of sci­en­tific advances that help to make test­ing meth­ods more accu­rate, or of tech­no­log­i­cal and com­mer­cial devel­op­ments. Their aims are to enhance and con­trol qual­ity, as well as to ensure trans­parency on the inter­na­tional mar­ket for olive oils, olive-pomace oils and table olives, and to pro­mote their con­sump­tion.

Considering the report pub­lished by UC Davis, there are sev­eral points this Expert Group wishes to clar­ify.

The results reported are for only 52 sam­ples of 19 brands. This is not sta­tis­ti­cally sig­nif­i­cant of the olive oil imported into the USA, because sam­ples traded in three cities of California are not rep­re­sen­ta­tive of the whole olive oil mar­ket in the USA; there­fore, the claim ques­tion­ing the true­ness-to-grade of the extra vir­gin olive oil imported into the USA is not real­is­tic.

There are no details of stor­age con­di­tions dur­ing ship­ping or time of test­ing. Without this infor­ma­tion it is impos­si­ble to con­sider the results to be reli­able. In addi­tion, the rec­om­men­da­tions stated on the prod­uct labels indi­cate that the oils must be kept in a cool dry place and must not be exposed to direct light in order to com­ply with their assigned grade clas­si­fi­ca­tion dur­ing their shelf life. We do not know if the non-com­pli­ance with the stan­dards was due to the orig­i­nal char­ac­ter­is­tics of the oils or to the stor­age con­di­tions dur­ing trad­ing.

The IOC trade stan­dard is under con­stant super­vi­sion by the IOC Chemistry Expert Group and con­tains all the nec­es­sary meth­ods to assess the qual­ity and purity of olive oil. Hence, it was not nec­es­sary to apply the non-offi­cial meth­ods cited in the report.

Most of the sam­ples were mis­clas­si­fied by the sen­sory analy­sis. The offi­cial method of the IOC was used, but was not applied accord­ing to the stan­dard­ised pro­ce­dure described in the method. When the grade assigned by the sen­sory analy­sis does not match the grade stated on the label clas­si­fi­ca­tion, the pro­ce­dure requires a sec­ond analy­sis to be per­formed by another IOC recog­nised panel. This was not done in the UC Davis study.

The UC Davis study places par­tic­u­lar empha­sis on the appli­ca­tion of non-offi­cial meth­ods and gives the impres­sion that the IOC meth­ods are not suf­fi­cient to assess the qual­ity and purity of olive oil. We would like to stress that some of the meth­ods used in this study are not IOC meth­ods, even though IOC meth­ods are avail­able (polyphe­nols and TAG) to assess the same para­me­ters.

It is also impor­tant to point out that the IOC does have an offi­cial method to detect low qual­ity oils or the addi­tion of soft refined oils obtained from low qual­ity oils (alkyl esters of fatty acids). Instead, the study used non-offi­cial meth­ods, – DAGs ‑and pyropheo­phy­tine – that had already been stud­ied by the IOC Chemistry Expert Group, which con­cluded that the scope of these meth­ods could not include the assess­ment of the qual­ity and purity of olive oil because these com­pounds change dynam­i­cally dur­ing the shelf life of the oil.

In this con­text, the UC Davis report claims that cheap refined oil was added to the oils; how­ever, all the para­me­ters (stig­mas­ta­di­enes and sterol com­po­si­tion) that detect the addi­tion of this type of oil were within the lim­its. Consequently, they can­not con­clude that refined oils were added.

As the IOC Chemistry Expert Group, we are very con­cerned about the final rec­om­men­da­tions of the study advo­cat­ing the imple­men­ta­tion of meth­ods that have not been proven to have any rela­tion­ship with the qual­ity or purity of olive oils.


The Group wishes to end by say­ing it is ready and will­ing to dis­cuss any new input to ensure the qual­ity and authen­tic­ity of olive oil.

Madrid (Spain), 8 October 2010

Ariel Pablo Buedo Lab. Molinos Río de la Plata (ARGENTINA); Hipólito García Toledo Lab. Agroalimentario Granada (ESPAÑA); José Ramón García Hierro Lab. Arbitral Agroalimentario Madrid (ESPAÑA); Arturo Cert Ventula Instituto de la Grasa Sevilla (ESPAÑA); Wenceslao Moreda Instituto de la Grasa Sevilla (ESPAÑA); Mª del Mar García González Lab. Central de Aduanas Madrid (ESPAÑA); Hermenegildo Cobo Martínez Lab. del SOIVRE Sevilla (ESPAÑA); Michel Blanc EXPERAGRO Saint-Cloud (FRANCE); Denis Ollivier SCL – Lab. de Marseille (FRANCE); Efstathia Kremmida-Christopoulou Lab. Technical Control for Consumer Protection Athens (GREECE); Effrosyni-Aikaterini Doumeni General Chemical State Laboratory Athens (GREECE); Lanfranco Conte Università di Udine (ITALIA); Luciana Di Giacinto C.R.A. – Centro di Ricerca per l’Olivicoltura e l’Industria Olearia Pescara (ITALIA); Fabrizio Apruzzese Direzione Centrale per l’Analisi Merceologica e per lo Sviluppo dei Laboratori Chimici Roma (ITALIA); Maurizio Servili Università degli Studi di Perugia (ITALIA); Angelo Faberi Laboratorio Centrale di Roma (ITALIA); Maria Celeste Gomes Autoridade de Segurança Alimentar e Económica Lisboa (PORTUGAL); Ana Helena Alegre Instituto Superior de Agronomia Lisboa (PORTUGAL); Bojan Butinar Univsersity of Primorska, Izola (SLOVENIA); Mounir Fahmy Khalil Agricultural Research Center Giza (EGYPT); Rabiei Zohreh University of Shahid Beheshti Evin- Tehran (IRAN); Zohar Kerem Hebrew University Rehovot (ISRAEL) ; Rafat Abdul-Munem Nimer Ahmad Industrial Chemistry Center of the Royal Scientif Society Amman (JORDAN); Nadia Maata Lab. Officiel d’Analyses et de Recherches Chimiques ; Casablanca (MAROC); Zakwan Bido Olive Oil Laboratories GCSAR Idleb (SYRIA); Kamel Ben Ammar Lab. de l’Office National de l’Huile Tunis (TUNISIE) ; Ümmühan Tibet Olive and Olive Oil Council of Turkey – UZZK (TURKEY)


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