Then there's the increasing popularity of raw and undercooked foods. A burger patty containing salmonella will be safe to eat once grilled to at least 145 degrees, and poultry is in the clear after reaching 165 degrees, according to the Department of Agriculture. But the bacterium can survive in the pink center of a seared slice of ahi tuna.
Salmonella can be hard to remove from fresh fruit and vegetables. "It's difficult to sterilize a tomato," said Dr. Ferric Fang, a professor of laboratory medicine and microbiology at the University of Washington in Seattle. "With cantaloupes, there's no way to wash them off because their skin is a little bit porous."
Once swallowed, salmonella is usually wiped out by stomach acid. But people who take antacids or heartburn medications give the pathogen a hand by making the stomach's pH level more tolerable. Salmonella that survive the stomach move on to the intestine, where they attach themselves to the lining and do their dirty work.
Ironically, antibiotics can also make people more vulnerable by wiping out some of the useful gut bacteria that protect against invading pathogens.
Scarfing lots of ice cream or French fries may also do salmonella a good turn, because the bug can cloak itself in a protective layer of fat, Fang said.
In the developed world, the most common disease-causing salmonella is the Typhimurium strain of Salmonella enterica. Victims typically feel symptoms of gastroenteritis within 12 to 72 hours of infection, which can last up to a week.
In about 3% or 4% of cases, salmonella hitches a ride into the bloodstream, requiring treatment with antibiotics. Nearly all patients recover.
Typhi, a more deadly strain, produces typhoid fever in the developing world. The bacterium travels through the bloodstream to the liver and spleen, where it changes its surface proteins to protect itself from the body's chemical defenses.
The CDC estimates that 21.5 million people are stricken by typhoid fever each year. Patients suffer high fevers, headaches, stomach pains, vomiting and diarrhea. If they aren't treated with antibiotics, about one in eight will die, said Groisman of Washington University.
When he accidentally ingested the Typhi organism himself, "it was like hell," he said. After initial symptoms passed, he felt incredibly weak for two months. "It was the worst disease I've ever had in my life."
For those charged with tracking down the source of an outbreak, salmonella cases are among the most difficult to solve. E. coli O157:H7 lurks in a more limited range of foods -- usually beef, lamb and produce -- but "salmonella can be on anything," said William E. Keene, a senior epidemiologist with the Oregon Public Health Division in Portland.
"There was all the flap about the jalapeno outbreak and the peanut butter outbreak," Keene said. In between, he said, "there were two others with hundreds of cases in dozens of states, and we have no idea what caused them."
In a sign of the times, the FDA's website contains a generic template that companies can use to announce salmonella-related recalls:
"XYZ Inc. of Anywhere, MS, is recalling its 5 ounce packages of 'Snackies' food treats because they have the potential to be contaminated with Salmonella," the mock-up begins.