In the cutthroat competition for supermarket shelf space, rivals had edged his high-protein, gluten-free, California-made nutrition bars out of a major American grocery chain. Dorf’s company, PureFit, had just three employees and under $10 million in sales, “but we didn’t curl up in a ball,” he recalled. “We kept fighting. We realized, there’s a lot more opportunity outside the U.S.” Today, PureFit exports to 20 countries from Switzerland to Singapore. Foreign sales rose 53 percent in two years, accounting for a quarter of revenue and making up for domestic losses. “International business saved my company,” said Dorf, 48, an avid cyclist who launched his brand 15 years ago because “most nutrition bars were dressed-up candy bars.” Foreign trade is in the news. President Barack Obama is pushing Congress to approve a massive trade deal with 12 nations, the Trans-Pacific Partnership. And the broader question of whether trade agreements create or destroy jobs has become a hot-button issue in presidential and congressional campaigns. For exporters such as Dorf, trade deals can mean fewer tariffs on their goods. And that could be good news for Southern California, which, with its massive ports, ethnically mixed population and diversified industries, is an export powerhouse. Los Angeles County produced a quarter of California’s $165 billion in merchandise exports in 2015. Orange County, with $19 billion, made up 11 percent, and the Inland Empire, with $9 billion, accounted for 5.4 percent.