The mountain of oranges, tangerines, lemons and more exotic fruits piled in the customs office at the Hidalgo international bridge in Texas on Thanksgiving Day would have made any grocer proud.

But the booty of Operation Gobble Gobble was destined for the industrial garbage disposal and left the cramped office filled with the sweet aroma of ground citrus. It was part of a U.S. Customs and Border Protection effort at the U.S.-Mexico border to protect U.S. agriculture from pests and diseases often carried by popular holiday ingredients.

"At this time of the year, we really do try to raise the awareness of the traveling public on the potential of introducing a pest or disease that could be damaging to American agriculture," said Diana Vlasik, agency's chief agriculture specialist at the international bridges in Pharr and Hidalgo, about 150 miles southwest of Corpus Christi.

Among the threats: the Mexican fruit fly, exotic Newcastle disease _ an illness fatal to poultry _ and bacteria that causes citrus greening, which has ravaged groves in Florida.

During the holidays, customs officers watch closely for certain fruits, raw pork and long stalks of sugar cane. Those products are banned year-round. But from Thanksgiving through the New Year, the border is jammed with less experienced travelers visiting relatives in Mexico or the U.S., as well as those who know better but are willing to risk confiscation and a fine to deliver key ingredients for a Christmas punch or tamales.

Generally, the searches are easier than those for narcotics, which are stowed in tires, gas tanks and secret compartments. These targets are usually out in the open or packed inside a cooler, an exception being some raw pork sausage packed into a diaper last year.

A few days after Thanksgiving, customs agriculture specialist John Tagle climbed into the bed of a pickup truck at the Hidalgo bridge and popped open a foam cooler. It contained beef, which is permissible. If it had been raw chicken, it would have suffered 1,400-degree temperatures in a customs incinerator.

"Usually the public doesn't have a problem with it," Tagle said. "It's just a couple apples. They'll say, 'It was just my lunch.'"

Confiscated fruit is sliced and inspected for signs of pests or disease. If an inspector sees something suspicious, it's placed in an envelope and mailed to a lab.