The company’s 2,200-acre orchard, an hour north of Sacramento, is an industrial marvel. The 1.3 million trees there are more like bushes, 6 to 10 feet tall and planted in neat, tight rows. The density lets a two-story mechanical harvester straddle the trees and strip away the olives to a conveyor that drops them into a truck, which delivers them to an on-site mill that can press 3,200 gallons of oil an hour. No olive is touched by hand. California Olive Ranch, a privately held company, estimates it accounted for 65 percent of the olive oil produced in the U.S. in 2015. ... Gregory Kelley, chief executive officer of California Olive Ranch, says it’s the mainstream sellers that need to defend the quality of their products. Europeans, he says, have long sold their dregs to unsophisticated Americans, like jug winemakers did in the 1970s. In a strategy said to be either self-defeating or brilliant, depending on who’s talking, Kelley often rails about what he calls the olive industry’s dirty secrets. He says much of the so-called extra-virgin oil sold in the U.S. is of unreliable provenance: adulterated with cheaper oils, processed with excessive heat that strips out healthful properties, or flawed by sloppy harvesting that can cause fermented or rancid-tasting oil.