In 1984, the Pope visited the restored 350-year-old Jesuit mission of Ste. Marie-among-the-Hurons in Midland, Ontario. After departing,1,600 hungry Ontario Provincial Police officers who had worked the ropes gathered for a boxed lunch. Of those 500 officers who chose ones with roast beef sandwiches, 423 came down with salmonella.

Those officers have shown, over the years, that a touch of the flu — as foodborne illness is often mistakenly called– is more than a couple of days praying at the porcelain goddess of foodborne illness. Some 5-10 per cent of those police officers have developed reactive arthritis that will plague them for life. The original research was published in 1995. Many additional studies have been published.

Maryn McKenna, a journalist, blogger and author of two books about public health writes in Scientific American that most people think of foodborne illness as an unpleasant few days of fever and diarrhea, but for some there may be lifelong consequences.

“People don’t understand the full consequences of foodborne disease,” says Kirk Smith of the Minnesota Department of Health, which lends its investigators around the U.S. “They think you get diarrhea for a few days and then you are better. They don’t understand that there is a whole range of chronic sequelae. And although any of them may not be common individually, when you put them together they add up to a lot.”

The consequences include reactive arthritis, urinary tract problems and damage to the eyes after Salmonella and Shigella infections; Guillain-Barré syndrome and ulcerative colitis (a chronic bowel inflammation) after Campylobacter infection; and kidney failure and diabetes after infection with Escherichia coli O157:H7.

A survey of 101,855 residents of Sweden who were made sick by food between 1997 and 2004 found, for instance, that they had higher-than-normal rates of aortic aneurysms, ulcerative colitis and reactive arthritis. A review of a major provincial health database in Australia revealed that people there who contracted any bacterial gastrointestinal infection were 57 percent more likely to develop either ulcerative colitis or Crohn’s disease, another chronic bowel condition, than people born in the same place and era who had not had such infections. And several years after a 2005 outbreak of Salmonella in Spain, 65 percent of 248 victims said they had developed joint or muscle pain or stiffness, compared with 24 percent of a control group who were not affected by the outbreak.

In May 2000 the drinking water in Walkerton, Ont., became contaminated with E. coli O157 after heavy rains washed manure from farm fields into its aquifer. More than 2,300 people, about half the town’s population, developed fever and diarrhea soon afterward. In 2002 the Ontario government funded the Walkerton Health Study to assess any health effects that might persist among the victims. In 2010 the study published its findings: compared with residents who did not get very sick, those who endured several days of diarrhea during the outbreak had a 33 percent greater likelihood of developing high blood pressure, a 210 percent greater risk of heart attack or stroke, and a 340 percent greater risk of kidney problems in the eight years following the outbreak.