Twenty-eight people are now dead after contracting listeria infections tied to contaminated cantaloupe, federal health officials reported Tuesday.

A total of 133 people have been sickened by the outbreak, which continues to claim victims more than a month after fresh, whole melons grown and packed at Jensen Farms in Holly, Colo., were recalled, the Centers for Disease Control and Prevention said.

Dirty equipment, poor sanitation and bad storage techniques were blamed for the outbreak, which has led to illnesses in 26 states, federal Food and Drug Administration officials announced last week. Members of Congress have asked Jensen Farm owners to appear at a staff briefing likely scheduled for next week and to bring all relevant documents from the outbreak.

Deaths tied to the listeria-tainted cantaloupe have been reported in a dozen states, including seven in Colorado, five in New Mexico, three in Kansas, two each in Louisiana, Missouri, New York and Texas and one each in Indiana, Maryland, Nebraska, Oklahoma and Wyoming. Four illnesses were related to pregnancy, with one illness diagnosed in a newborn and one miscarriage reported.

Ed Andrieski / AP

Cantaloupes rot in the afternoon heat on a field on the Jensen Farms near Holly, Colo., last month. Whole fruit contaminated with listeria have been blamed for 25 deaths in the worst food poisoning outbreak in the U.S. in a quarter century.

Now that federal investigators have identified dirty equipment, faulty sanitation and bad storage practices at a Colorado farm as the likely cause of a cantaloupe listeria outbreak that has killed 25 people, top U.S. food safety experts say there's one actor in this deadly drama that shouldn't be blamed: The consumer.

No amount of washing, scrubbing, bleaching or peeling would have cleaned cantaloupes contaminated by Jensen Farms' packing practices enough to remove listeria bacteria that has sickened at least 123 people and killed 25 in the deadliest outbreak in a quarter-century.

"There's nothing consumers could have done," said Dr. Doug Powell, a professor of food safety at Kansas State University in Manhattan, Kan.

Federal Food and Drug Administration officials reported Wednesday that standing pools of water, inaccessible drains, hard-to-clean equipment and failure to cool cantaloupes fresh from the field before placing them in cold storage all likely contributed to the growth and spread of four strains of listeria bacteria at the Jensen Farms packing site in Granada, Colo.

The cold, moist environment maintained over time is exactly what listeria needs to thrive, said Dr. Mike Osterholm, director of the Center for Infectious Disease Research and Policy and a food safety expert at the University of Minnesota.

In addition, listeria could have been introduced into the packing center from sporadic bacteria in the field or from a dump truck that hauled culled cantaloupe back and forth to a cattle yard and then parked next to where the whole melons were being processed. Cattle are known reservoirs for listeria.

The bacteria clearly contaminated a huge proportion of the more than 310,000 cases of cantaloupe -- between 1.5 million and 4.5 million fruit -- that were recalled by Jensen Farms in mid-September, said Powell.

"Given that 25 people are dead, this was a massive contamination to have that impact," he said.

It's not clear whether people were infected by bacteria that clung to the fruit's porous, bumpy rind, whether the germs somehow migrated into the flesh of the fruit, or whether people spread contamination through the fruit by slicing it with a knife, Powell said. Good hygiene and food safety practices can lessen the chance of infection, but the contamination shouldn't be there in the first place.

"The idea that this is the consumer's responsibility is just nonsense," he said. "What's missing is any verification that individual farmers are doing what they're supposed to be doing."

Preventing the conditions that allowed the outbreak to occur and continue is the primary goal of the FDA's ongoing food safety efforts said the agency's commissioner, Dr. Margaret Hamburg.

“If we’re to have a food safety system that truly prevents foodborne illness, we must all practice prevention,” she told reporters.

That's particularly incumbent on melon growers, who have felt the brunt of consumer fear as sales of cantaloupes have plummeted.

"Don't rely on paperwork if your brand relies on selling safe food," Powell said. "Any commodity is only as good as its worst grower."

Related posts:

Dirty equipment blamed for deadly outbreak in cantaloupe

Illnesses and deaths tied to listeria-tainted cantaloupe continued to rise Tuesday, with federal health officials reporting 123 sickened and 25 dead in the ongoing food poisoning outbreak.

More than 310,000 cases of cantaloupe recalled by Jensen Farms of Holly, Colo., are long gone from the shelves and pantries of stores and should be long past storage in refrigerators. But all of the victims in the outbreak that has now affected 26 states became sick on or before July 31, and more are likely to be diagnosed because people can develop listeriosis up to two months after eating contaminated food, according to the Centers for Disease Control and Prevention.

The deadliest outbreak of food poisoning in more than 25 years has caused fatalities in a dozen states: six in Colorado, five in New Mexico, two each in Kansas, Louisiana, New York and Texas and one each in Indiana, Maryland, Missouri, Nebraska, Oklahoma and Wyoming. People who've died have ranged in age from 48 to 96 years, with a media age of 87.

Illnesses have occured in people younger than 1 to 96, with a median age of 78. Most illnesses have occured in people older than 60. Four illnesses were related to pregnancy, including a newborn who fell ill. One miscarriage has been reported.

Federal Food and Drug Admnistration officials have not disclosed the cause of the outbreak cause by four strains of listeria monocytogenes.

An outbreak of listeria infections tied to contaminated Colorado cantaloupe has now sickened 116 people and left 23 dead, federal health officials reported Wednesday, making this the deadliest outbreak in more than 25 years. In addition, one pregnant woman who became ill had a miscarriage.

The rising toll reflects illnesses and deaths in 25 states caused by four outbreak strains of listeria, according to the Centers for Disease Control and Prevention. All of the illnesses began on or after July 31, but more are expected because people can develop listeriosis up to two months after eating contaminated food.

An investigation into the cause of the outbreak linked to recalled cantaloupe from Jensen Farms in Holly, Colo., has not yet concluded, a federal Food and Drug Administration spokesman said.

Deaths have been reported in a dozen states, including five in Colorado; five in New Mexico; two each in Kansas, Louisiana and Texas; and one each in Indiana, Maryland, Missouri, Nebraska, New York, Oklahoma and Wyoming.

Miscarriage blamed on listeria-tainted cantaloupe

The 23 deaths have surpassed 21 deaths tied to a listeria outbreak in 1998 tied to contaminated hot dogs and deli meat.

Illnesses have been reported in people aged 22 to 96, with a median age of 78. Most of those sickened are older than 60. Four of the illnesses were related to a pregnancy; one was diagnosed in a newborn and three were diagnosed in pregnant women.

Recalls tied to the outbreak include more than 300,000 cases of whole cantaloupes from Jensen Farms, and two different recalls of cut cantaloupe: A Sept. 23 recall of nearly 600 pounds of fresh cantaloupe from Carol's Cuts LLC of Kansas and an Oct. 6 recall of nearly 5,000 individual packages of cantaloupe by Fruit Fresh Up Inc. of Depew, N.Y.

Read more on food safety issues:

As farmers thrive, so do concerns

Flood of food imported, just 2 percent inspected