Eric Jensen is the co-owner of Jensen Farms in Holly, Colo., that has been identified by health officials as the source of a national listeria outbreak.

HOLLY, Colo. — Eric Jensen surveys his dusty cantaloupe field and seems equally stunned and puzzled at the fate that has befallen his crop: row upon row of melons rotting on the vine.

Jensen is the co-owner of the Colorado farm where health officials say a national listeria outbreak originated, making his withering fields the epicenter of a food scare that has sickened dozens of people from Wyoming to Maryland and caused 16 deaths.

Jensen has no idea how his cantaloupes became infected, and neither do the Food and Drug Administration investigators who have intermittently been in this town of 800 people near the Kansas border since the outbreak started earlier this month.

Regardless of how it happened, the situation has left the town and farm reeling and in fear. Jensen had to quit growing and shipping cantaloupes after the outbreak was discovered — a staggering blow to a region where cantaloupe has always been a proud local tradition. Until the listeria infections started showing up, Holly’s field workers would bring melons into town to share, just as they have for generations. And it wasn’t uncommon for Holly residents to stop by Jensen Farms to buy freshly picked cantaloupe. Now, not even the local grocery store has any of the fruit.

No one in Holly has been sickened, but people are frightened by the prospect of contracting listeria. The bacteria can have an incubation period of a month or more, and it principally affects the elderly and those with compromised immune systems.

“I ate that cantaloupe, and I gave some of it to my 97-year-old mother,”‘ said Wanda Watson, co-owner of the Tasty House Cafe. “I’m watching her real close. It’s scary because it could be up to two months before you get sick.”

Sherri McGarry, a senior adviser in the FDA’s Office of Foods, said the agency is looking at the farm’s water supply and the possibility that animals wandered into Jensen Farms’ fields, among other things, in trying to figure out how the cantaloupes became contaminated. Listeria bacteria grow in moist, muddy conditions and are often carried by animals.

The water supply for farms in the Holly area comes from wells and irrigation ditches that tap the nearby Arkansas River. There’s no shortage of thoughts around town about the potential causes.