ROSTRENEN, France – On a velvety green patch of the French countryside, organic farmer Jean Cabaret gave a little shudder. A looming trade deal with the United States, he fears, may make his worst culinary nightmare come true: an invasion of Europe by American "Frankenfoods."

"Hormone-boosted beef. Chlorine-washed chicken. Genetically altered vegetables. This is what they want for us," warned Cabaret, standing before his majestic herd of free-range cows. "In France, food is about pleasure, about taste. But in the United States, they put anything in their mouths. No, this must be stopped."

In Europe, this is a season of angst – even paranoia – over a historic bid to link the United States and the 28-nation European Union in the world’s largest free-trade deal.

Passage of the Transatlantic Trade and Investment Partnership (TTIP) could be a globalization milestone, creating a megamarket of 800 million consumers from Alaska to Finland, Hawaii to Greece. Import duties – many of which already are low – could be further reduced. More important, the deal could finally tackle nontariff barriers, including differing data-protection and food-safety standards that have long stood in the way of transatlantic commerce.

But even as time runs out for President Obama to sign a deal before leaving office, European and U.S. advocates have been surprised by the increasingly hostile reception on this side of the Atlantic. It is jeopardizing the chances of a deal that proponents say could create millions of new jobs by dramatically boosting U.S.-E.U. trade.