“Top-selling brands including Bertolli, Filippo Berio, Carapelli, Pompeiian, Colavita, Mazola and Carapelli all had bottles that flunked the test — containing instead a cheaper virgin olive oil, the study by the university’s Olive Center found. Even a brand carrying the name of TV host Rachael Ray — who frequently touts her supposedly extra virgin olive oil — flunked the testing on two of three samples.”

The North American Olive Association has criticized the study, saying the results are causing confusion:

“Like too many studies about food, a recent University of California at Davis study on olive oil is causing confusion among consumers. In the U.S. market, 99 percent of the olive oil sold is imported, and the largest olive oil trade association is fighting to set the record straight about the authenticity, quality and health benefits of imported olive oils.

” ‘There are often rumors that products labeled as olive oil may not be 100 percent authentic,’ said Bob Bauer, president of the North American Olive Oil Association (NAOOA), a trade association representing marketers, packagers and importers of olive oil in the United States, Canada and their respective suppliers abroad.

“For 20 years, the NAOOA, in conjunction with the International Olive Council (IOC), which is the recognized worldwide body that sets quality standards for the olive oil industry, has been rigorously testing oils sold in the U.S. to verify quality and authenticity. Results prove that on average, 99 percent of the olive oil sold in stores throughout the U.S. meet the internationally recognized standards.”

Last month, I wrote about the Department of Agriculture’s move to enforce new olive oil regulations.