`Davis Researchers Put Olive Oil 'Fridge Test' to the Test - Olive Oil Times


Davis Researchers Put Olive Oil 'Fridge Test' to the Test

By Nancy Flagg
Mar. 12, 2013 00:01 UTC

On a recent episode of the Emmy Award-win­ning tele­vi­sion pro­gram, The Dr. Oz Show,” Dr. Oz warned his audi­ence that more than two-thirds of extra vir­gin olive oil sold was not pure EVOO. He rec­om­mended that view­ers pay­ing pre­mium prices to get EVOO should con­duct a home test to find out if their pur­chase is pure EVOO qual­ity. Dr. Oz advised buy­ers to put their bot­tle of EVOO into the refrig­er­a­tor to see if the oil solid­i­fies. If it does solid­ify, they can be pretty sure it’s pure,” said Dr. Oz; though he also cau­tioned that the test is not 100 per­cent fool­proof.“

Some experts debunk the so-called Fridge Test,” includ­ing expert taster Richard Gawel who called the test a myth” and the North American Olive Oil Association that described it as com­pletely false and mis­lead­ing.”

The University of California Davis Olive Center recently put the Fridge Test to the test. Olive Center Director Dan Flynn, who was a guest on Dr. Oz’s show, said that there were many calls and emails to his office, super­mar­kets and pro­duc­ers after the pro­gram aired. Viewers who had tried the test and found their oil failed had con­cerns and ques­tions. Flynn said Olive Center Research Director Selina Wang had the idea for the team to con­duct its own research exper­i­ment to help clear up the con­fu­sion.”

Flynn told Olive Oil Times that the results of the exper­i­ment, which were released today, showed that the Fridge Test is an unre­li­able indi­ca­tor of olive oil qual­ity.

Seven oil sam­ples, includ­ing EVOO, lesser grade olive oils, olive oil blends and non-olive oils were placed in a refrig­er­a­tor and checked at inter­vals up to 180 hours. Although no sam­ples fully solid­i­fied, a sam­ple of EVOO mixed with up to 50 per­cent lesser grade olive oil con­gealed in the bot­tles, mean­ing it could be inter­preted as pass­ing the refrig­er­a­tor test even though it was not pure EVOO. The study con­cluded that the Fridge Test is not reli­able for deter­min­ing oil purity or qual­ity.

If the Fridge Test can­not be relied on, what can con­sumers do? Flynn advises con­sumers to buy darker bot­tles that pro­tect the oil from light, pur­chase oil within 15 months of the har­vest date (which should be printed on the label) and look for cer­ti­fi­ca­tion seals.

Flynn rec­om­mends cer­ti­fi­ca­tions that include both a chem­i­cal pro­file test and a sen­sory eval­u­a­tion, such as the Australian and Californian cer­ti­fi­ca­tions. The NAOOA, which rep­re­sents American olive oil importers, also con­ducts a qual­ity seal pro­gram that includes analy­ses by a cer­ti­fied taste panel.

Chemical tests alone are not enough to tell if an oil tastes good,” said Flynn.


Refrigeration is not reli­able in detect­ing olive oil adul­ter­ation, UCD Olive Center


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