From the time food is grown on the farm until it reaches your table, it is at risk for tampering -- and the government believes terrorists may well try to make food a weapon.
"Agro terrorism is clearly one of the pillars of terrorism that we worry about," said Vahid Majidi, assistant director for the FBI Weapons of Mass Destruction Directorate.
Former U.S. counterterrorism czar Dick Clarke agreed.
"There are clearly people in other countries, who are hostile to the United States, who have the knowledge to be able to wipe out a food crop or to be able to poison a food crop," said Clarke, now an ABC News consultant.
It's the kind of nightmare scenario that used to keep Tommy Thompson, former head of Health and Human Services, up at night.
"I'm always worried that there's that possibility," Thompson said. "Because all we've had to do is see how E. coli has been able to be put on spinach and has been grown on spinach and the tremendous disruption in families and communities all across America."
E. coli poisoning, foot and mouth disease and mad cow disease are just some of the ugly possibilities.
Government investigators say there's no evidence linking the current E. coli outbreak -- in which tainted spinach has caused at least 171 known cases in 25 states, according to the FDA -- to terrorism. But those same investigators are keenly aware that America's food supply is vulnerable to attack. An international meeting on how to fight agro-terrorism starts Monday in Kansas City.
Government agencies have held mock exercises to see what would happen if the food supply was compromised. The results were catastrophic.
"What happened was utter chaos," said Sen. Patrick Roberts, R-Kan. "We lost almost the entire livestock herd of the United States, all export stock. We had panic at the grocery stores."
How real is the threat? Since the Sept. 11 attacks, the government has developed a national warning system for the agricultural industry.
"We are working very closely with Homeland Security, FDA, USDA," Majidi said. "So these are our federal partners as well as our industrial partners."
The government is also spending millions of dollars on biological weapons research and planning is underway for a new bioterror center.
Officials say that this is not science fiction. They believe an attack on the food supply could be surprisingly easy.