Heightened border security between the United States and Mexico wouldn’t just impact the flow of human traffic across the two nation’s borders; it also could affect the flow of perishable fruits and vegetables from Mexico into the United States and Canada, especially with the winter months coming.

That’s among concerns expressed by agricultural officials from the three nations who gathered in Denver this week to discuss trade and rural development. Officials indicated longer wait times at border crossings could imperil produce that must get to market quickly to avoid spoilage.

The 26th Tri-National Agricultural Accord wrapped up Friday at Denver’s Stapleton Renaissance Hotel. The four-day conference met the same week federal officials from the three nations are haggling over changes to the North American Free Trade Agreement (NAFTA). President Donald Trump promised during his campaign to renegotiate the two-decade old agreement, to the consternation of some in the agricultural industry, which fears changes could negatively impact U.S. exports. Trump’s opposition to NAFTA is based on his belief that it has cost U.S. citizens jobs.

Negotiations have reportedly stalled over insistence by the Trump administration that NAFTA be renewed for only five years, a proposal the U.S. Chamber of Commerce calls a “poison pill.”

The Tri-National Accord brought together state, provincial, and federal officials to discuss trade opportunities and rural development. Attending were officials from four Canadian provinces, 10 states in Mexico and 34 in the United States, as well as officials from the U.S. Department of Agriculture and their Canadian and Mexican counterparts.

The four days included multiple multi-nation discussions that were closed to the public. At least two sessions focused on something other than NAFTA: the recent batch of hurricanes, wildfires and other disasters that have caused billions in damage in all three nations, and a look at Colorado’s legalization of cannabis and its impact on agriculture.

But NAFTA was clearly on the minds of most, with a plea from agricultural officials to Washington to adopt part of the Hippocratic oath when it comes to NAFTA: “first, do no harm.”

Steven Reviczky is commissioner of agriculture for Connecticut and president of the National Association of State Departments of Agriculture, which sponsored the accord. He said Wednesday that the summit’s conversations on NAFTA would be critical and that the U.S. delegation at the summit, the largest in the event’s history, speaks to the importance of NAFTA for states’ agricultural sectors. “It’s imperative that we as state and provincial agriculture leaders speak together on the importance of trilateral relationships, the importance of NAFTA for agriculture and the importance of working together to build a prosperous North American economy,” Reviczky said.

Jeff Leal, the Ontario commissioner for agriculture, food and rural affairs, said that while the nations may have their differences, ‘we share more than borders” and all hope to see a benefit in modernizing the NAFTA agreement.

“NAFTA has served us well at home, and made our countries more competitive and a force on an international basis,” a message that key decisionmakers need to hear, he said.

But it was Mexico’s Hector Padilla, secretary of rural development for the Mexican state of Jalisco, who sounded the alarms most loudly on NAFTA negotiations. He warned that Mexico is already looking for beef exports from other nations, such as Brazil and Argentina. Colorado beef is the state’s number one exported commodity, and Mexico is the state’s number two beef importer; Canada is number one in Colorado beef imports. Padilla pointed out that in some U.S. states, 50 percent of food exports go to Mexico.

Padilla addressed the potential for U.S. tariffs on Mexican exports, noting that tariffs will only drive up costs for U.S. consumers on Mexican goods, such as produce. But Padilla also hinted that NAFTA negotiations could come up with an exemption for agriculture, noting that uncertainty about NAFTA is impacting economic vitality for the industry.

“We are a region that compliments each other,” Padilla said. “We’re dynamic in our production and trade and in creating jobs and benefiting consumers.” Mexico has had good relationships with its NAFTA trading partners, he added, and the delegation will make working together a top priority.

Thursday night, the three delegations signed off on a communique that highlighted their desire to keep the dialogue going. The U.S.-Mexico delegates approved joint statements on the importance of agricultural labor and strong relationships between the two countries. The Canada-U.S. delegates also signed off on a joint statement on the importance of relationships between the two countries on agriculture.

At the summit’s conclusion, Colorado Commissioner of Agriculture Don Brown called the event a “tremendous opportunity to discuss the importance of NAFTA and the value of cooperative partnerships.”