Reynosa, Mexico ? Indian pigeon peas, Mexican cilantro, Turkish laurel leaves — any food headed for the American market — will be more closely examined as of today under new rules to thwart bioterrorists.

Under the Bioterrorism Act, the U.S. government requires 400,000 food handling companies — at home and abroad — to register all products with the Food and Drug Administration.

While the new regulations affect both imported and domestic food, foreign exporters fear they will be hit the hardest. Many say it could drive them out of the U.S. market, although some hope the new law will expedite trade.

The law requires those exporting food to the United States to give American inspectors advance notice before shipments arrive — two hours for those crossing the border by truck, four hours for those on planes or trains, and eight if landing by ship.

Although there has not been a terrorist attack on the U.S. food supply, Americans have been hit by an anthrax scare and FDA officials believe green onions that originated in Mexico infected hundreds of U.S. residents with hepatitis.

The FDA said that as of Wednesday, nearly 131,000 food handling companies had registered — about 68,000 of which were outside of the United States.

Mexican customs broker Janet Martinez said many of her clients were not even aware of the new law. She doubts they will register, let alone meet the new requirements.

“In Mexico, there are places where there isn’t even a phone,” Martinez said. “A lot of our clients are small producers and they are not at the level to comply with what the FDA is asking. They are going to be hit the hardest.”

Javier Navarro, of the vegetable exporting company Nueva Era in the Mexicali Valley, said the new regulations signaled the beginning of trade roadblocks to come.

“There is a lot of uncertainty in all of this,” said Navarro, whose company exports $8 million worth of cilantro, basil, spinach, leeks and other vegetables to the United States each year. “We hear this is the first step in many more and tougher requirements the FDA will put in place. We don’t have proof to show this, but at times it feels it is about protecting the American market.”

FDA spokesman Michael Herndon said the rules were created to protect against a possible bioterrorism attack.

“The FDA goal is not to interrupt the flow of safe food imports,” he said. “But just like with anything new, you’ll have some bumps and bruises.”

In India, exporters say the new rules could result in product losses.

Subodh Shah, deputy manager of international marketing for Vadilal, a company that exports canned and frozen foods to the United States, said his products must be kept at near freezing temperatures or they will spoil. Delays at ports of entry could cost him entire shipments.

Herndon said firms will have at least four months to get acquainted with the new law and comply with the regulations.

“We will allow for a period of education rather than enforcement,” he said.

The FDA and U.S. Customs have agreed to share information so that companies won’t have to submit details about incoming shipments twice. Customs already requires companies to register imported products, but the FDA registration involves a much more detailed questionnaire. The FDA registration will enable the agency to track food as it leaves packing plants and arrives in ports.

Customs officers also will conduct FDA inspections, helping enforce bioterrorism regulations in about 300 ports of entry, Herndon said. About 1,800 customs officers could ultimately be trained to do inspections based on FDA guidelines, filling the gaps where the FDA lacks personnel.

Kazim Gurel, deputy chairman of the board of the Turkish company Kutas, which exports more than $10 million in oregano, laurel leaves, sage and other spices to the United States, said the biggest headache for him will be additional paperwork.

“At the end of the day, there will be added documentation. It involves more labor,” he said. “But I wouldn’t say it’s a barrier to trade.”

Jorge Lopez, who helps run his family-owned vegetable exporting company in Mexico, hopes the regulations will mean less time wasted at the border.

Each day, his truck — loaded with 18 tons of edible cactus — takes an average of four hours to cross from Reynosa to Pharr, Texas.

“Far from seeing this as a roadblock, it’s all about tracking the products, controlling what goes in and what could be better if everything is done efficiently,” he said.

Still, Lopez wonders how effective the inspections would be in intercepting hazardous foods.

“When you think about it,” he said, “they are always checking for illegal drugs and they still get through.”