` Davis Olive Center Responds to IOC Criticism of Report

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Davis Olive Center Responds to IOC Criticism of Report

Feb. 22, 2011
By Lori Zanteson

Recent News

By Lori Zan­te­son
Olive Oil Times Con­trib­u­tor | Report­ing from Los Ange­les

Last year’s report by the UC Davis Olive Cen­ter, Tests indi­cate that imported extra vir­gin’ olive oil often fails inter­na­tional and USDA stan­dards,” caused a stir in the olive oil indus­try and beyond when pop­u­lar media trum­peted the results with fan­tas­tic head­lines like That Olive Oil Is No Vir­gin”. The con­tro­ver­sial study by the Cal­i­for­nia uni­ver­sity stated that 69 per­cent of imported olive oil sam­ples labeled extra vir­gin olive oil” failed inter­na­tional chem­i­cal and sen­sory stan­dards for extra vir­gin clas­si­fi­ca­tion.

The Chem­istry Expert Group of the Inter­na­tional Olive Coun­cil (IOC) took excep­tion to the find­ings andpub­lished a rebut­tal, cit­ing the small sam­pling size, unknown stor­age con­di­tions, chem­i­cal test­ing meth­ods, and sen­sory analy­ses of the study.

Now the authors of the report have issued their own pointed response to these crit­i­cisms, defend­ing each excep­tion brought by the IOC chemists in a state­ment first pub­lished on the web­site of the Amer­i­can Oil Chemists’ Asso­ci­a­tion.

In my view,” the study’s lead sci­en­tist, Dr. Edwin Frankel, wrote in an email to Olive Oil Times, the IOC has been very politi­cized in estab­lish­ing stan­dard for exported extra vir­gin olive oils. In Cal­i­for­nia, we hope to be able to develop bet­ter stan­dards in sup­port of our locally pro­duced extra vir­gin olive oils.”

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UC Davis Stands Behind the Report
Edwin N. Frankel, Rod­ney J. Mailer, Selina Wang, Charles F. Shoe­maker, and Dan Flynn

The response to the Uni­ver­sity of Cal­i­for­nia Davis report (“Tests indi­cate that imported extra vir­gin’ olive oil often fails inter­na­tional and USDA stan­dards,” UC Davis Olive Cen­ter, July 2010) has ranged from know­ing nods to sharp crit­i­cisms such as those offered by the Chem­istry Expert Group of the Inter­na­tional Olive Coun­cil (IOC; Madrid, Spain). We respect the mem­bers of the Expert Group but stand fully behind the report.

To quickly review the source of the con­tro­versy, the UC Davis study found that 69% of the imported olive oils that we tested failed the IOC’s offi­cial sen­sory test, with that result con­firmed in 31% of the cases by the IOC’s tests for UV absorbance of oxi­da­tion prod­ucts, and in 86% of the cases by Ger­man dia­cyl­glyc­erol (DAG) and pyropheo­phytin (PPP) tests.

The report was com­pleted by the UC Davis Olive Cen­ter and the Aus­tralian Oils Research Lab­o­ra­tory. The Aus­tralian lab­o­ra­tory is rec­og­nized by the IOC and the AOCS for pro­fi­ciency in con­duct­ing IOC chem­i­cal and sen­sory tests.

While the Expert Group’s state­ment does not ade­quately rep­re­sent the diver­sity of opin­ion among mem­bers of the panel, many of whom were not offered an oppor­tu­nity to review or sign the state­ment, we will respond to the state­ment as writ­ten.

Sta­tis­ti­cal sig­nif­i­cance. The IOC Expert Group asserts that the UC Davis report is not sta­tis­ti­cally sig­nif­i­cant,” but actu­ally UC Davis ana­lyzed sam­ples at four times the rate of the IOC’s own qual­ity con­trol pro­gram (on an annu­al­ized basis). Accord­ing to an offi­cial IOC report avail­able from the IOC web­site, the IOC ana­lyzed an aver­age of 116 extra vir­gin sam­ples per year in 2008 and 2009 col­lected from the United States and Canada. These coun­tries have a com­bined pop­u­la­tion of 340 mil­lion, so the IOC ana­lyzed one sam­ple for every 2.93 mil­lion peo­ple. The UC Davis study is based on 52 sam­ples col­lected from the state of Cal­i­for­nia, which has a pop­u­la­tion of 38 mil­lion. Thus, the UC Davis study ana­lyzed one sam­ple for every 730,000 peo­ple, or at four times the rate of the IOC.

Stor­age con­di­tions. The Expert Group, while accept­ing our find­ings that many oils were non­com­pli­ant with IOC stan­dards, con­tends that it is impos­si­ble to con­sider the results reli­able” with­out infor­ma­tion on ship­ping or time of test­ing. Here is the fac­tual infor­ma­tion: All oil sam­ples were col­lected and man­aged at UC Davis by a sin­gle mem­ber of the research team. Sam­ples were col­lected within a seven-day period when day­time tem­per­a­tures ranged between 52°F and 56°F (11°C and 13°C). The sam­ples were in tran­sit to UC Davis for no more than nine hours. The research team promptly coded, wrapped in foil, pack­aged for ship­ment, and shipped the sam­ples to the Aus­tralian lab, with the sam­ples arriv­ing in Aus­tralia five days after ship­ment. The Aus­tralian Oils Research Lab­o­ra­tory is IOC-cer­ti­fied and fol­lows IOC qual­ity stan­dards relat­ing to time of test­ing and all other para­me­ters.

Chem­i­cal meth­ods. The Expert Group states that the IOC trade stan­dard con­tains all the nec­es­sary meth­ods to assess the qual­ity and purity of olive oil … hence it was not nec­es­sary to apply the nonof­fi­cial meth­ods cited in the report.” While we appre­ci­ate the work that the IOC has per­formed in devel­op­ing stan­dards, we expect that few chemists would agree that IOC stan­dards are fully ade­quate, and we feel strongly in sup­ple­ment­ing IOC meth­ods with addi­tional tests (DAG and PPP) adopted in Ger­many and Aus­tralia. In fact, the German/Australian chem­i­cal tests con­firmed neg­a­tive sen­sory results for 86% of the cases, whereas the IOC chem­i­cal tests con­firmed neg­a­tive sen­sory results for just 31% of the cases.

The Expert Group also states that it rejected the DAG and PPP tests because these com­pounds change dynam­i­cally dur­ing the shelf life of the oil.” Using this rea­son­ing, the panel would also need to dis­avow IOC tests for free fatty acid­ity, con­ju­gated dienes (K232) and trienes (K270), and per­ox­ide val­ues, which all would change dur­ing the shelf life of the oil. The Expert Group also says that the UC Davis study can­not con­clude that refined oils were added because the stig­mas­ta­di­enes and sterol pro­files were in com­pli­ance with IOC stan­dards. Actu­ally, the UC Davis study indi­cated that the addi­tion of refined oils was a pos­si­bil­ity, and our study team con­cluded if any of the sam­ples were adul­ter­ated, it is most likely that the adul­ter­ant was refined olive oil rather than refined nut, seed, or veg­etable oils.”

Sen­sory analy­sis. The Expert Group, while accept­ing our find­ing that many of the oils failed the sen­sory analy­sis con­ducted by an offi­cial IOC panel, says that IOC pro­ce­dures require a sec­ond analy­sis to be per­formed by another IOC panel, and faults the UC Davis study for not hav­ing a sec­ond test con­ducted. Actu­ally, the IOC does not require a sen­sory panel to get a sec­ond opin­ion when a panel finds that an oil sam­ple has failed an ini­tial test.

Although the UC Davis report was just one study, and should be viewed as such, we should note that seri­ous olive oil qual­ity prob­lems were found by Con­sumer Reports in Sep­tem­ber 2004, Der Fein­schmecker in May 2005, Aus­tralian Oils Research Lab­o­ra­tory over sev­eral years, the Uni­ver­sity of the Repub­lic in Uruguay in Octo­ber 2010, and the Depart­ment of Health in Andu­lacía, Spain, in Novem­ber 2010. With the United States now being the third-largest con­sumer of olive oil in the world, this issue deserves con­tin­ued research.

We encour­age read­ers to exam­ine our Report and Appen­dix, and assess the valid­ity of the study for them­selves. We reit­er­ate our desire to work col­lab­o­ra­tively with the IOC to ana­lyze the qual­ity of olive oil in the United States. Let’s test it and taste it together.

Edwin N. Frankel is an adjunct pro­fes­sor, Selina C. Wang is a research asso­ciate, Charles F. Shoe­maker is pro­fes­sor and leader of the UC Davis Olive Oil Chem­istry Lab­o­ra­tory, and Dan Flynn is the exec­u­tive direc­tor of the UC Davis Olive Cen­ter, all at the Uni­ver­sity of Cal­i­for­nia, Davis. Rod­ney Mailer is a research fel­low at the Aus­tralian Oils Research Lab­o­ra­tory in Wagga Wagga, Aus­tralia.

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