Foodborne illness is America’s secret epidemic. Every year three thousand people, the equivalent of a small town, die of food poisoning in the United States, and around 130,000 are hospitalized. It can be a decidedly horrible way to die. In December 1992, Lauren Beth Rudolph had a cheeseburger at a Jack in the Box restaurant in Carlsbad, California. Five days later, she was taken to the hospital suffering excruciating abdominal cramps and bloody diarrhea, and her condition was rapidly deteriorating. In the hospital, she suffered three massive cardiac arrests and died. She was six years old.
Over the next few weeks, seven hundred customers who had visited seventy-three Jack in the Box restaurants in four states grew ill. Three of them died. Others suffered permanent organ failure. The source was E. coli in undercooked meat. According to Food Safety News, the Jack in the Box company knew that its hamburgers were being undercooked “but had decided that cooking them to the required 155 degrees made them too tough.”
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Equally pernicious is salmonella, which has been called “the most ubiquitous pathogen in nature.” According to a USDA study, about a quarter of all chicken pieces sold in stores are contaminated with salmonella. Some 40,000 cases of salmonella infection are reported in the United States each year, but the real number is thought to be much higher. By one estimate, for every reported case a further 28 go unreported. That works out to 1,120,000 cases a year. There is no treatment for salmonella poisoning.
Salmonella has nothing to do with spawning fish. It is named for Daniel Elmer Salmon, a U.S. Department of Agriculture scientist, though it was actually discovered by his assistant Theobald Smith, yet another of those forgotten heroes of medical history. Smith, born in 1859, was the son of German immigrants (the family name was Schmitt) in upstate New York and grew up speaking German, so was able to follow and appreciate the experiments of Robert Koch more quickly than most of his American contemporaries. He taught himself Koch’s methods for culturing bacteria and was thus able to isolate salmonella in 1885, long before any other American could do so. Daniel Salmon was head of the Bureau of Animal Husbandry at the U.S. Department of Agriculture and was primarily an administrator, but the convention of the day was to list the bureau head as lead author on the department’s papers, and that was the name that got attached to the microbe. Smith was also robbed of credit for the discovery of the infectious protozoa Babesia, which is wrongly named for a Romanian bacteriologist, Victor Babeş. In a long and distinguished career, Smith also did important work on yellow fever, diphtheria, African sleeping sickness, and fecal contamination of drinking water, and showed that tuberculosis in humans and in livestock was caused by different microorganisms, proving Koch wrong on two vital points. Koch also believed that TB could not jump from animals to humans, and Smith showed that that was wrong, too. It was thanks to this discovery that pasteurization of milk became a standard practice. Smith was, in short, the most important American bacteriologist during what was the golden age of bacteriology and yet is almost completely forgotten now.
Responsibility for food safety is split among a raft of federal agencies in America in a way that rather defies logic. The Food and Drug Administration is responsible for the skin of sausages, but the Food Safety and Inspection Service is responsible for what goes inside them. Cheese pizzas are looked after by one agency, but meat pizzas by another. And so it goes through a whole range of foodstuffs. Altogether fifteen agencies have a regulatory role in some aspect or other of American food safety. No one agency has overall control.
Incidentally, most nausea-inducing microbes need time to proliferate inside you before they make you sick. A few, like Staphylococcus aureus, can make you ill in as little as an hour, but most take at least twenty-four hours. As Dr. Deborah Fisher of Duke University told The New York Times, “People tend to blame the last thing they ate, but it’s probably the thing before the last thing they ate.” Actually, many infestations take far longer than that to manifest. Listeriosis, which kills about three hundred people a year in America, can take up to seventy days to show symptoms, which makes tracking down a source of infection a nightmare. In 2011, thirty-three people died of listeriosis before the source—cantaloupe from Colorado—was identified.
The largest source of foodborne illness is not meat or eggs or mayonnaise, as commonly supposed, but green leafy vegetables. They account for one in five of all food illnesses.
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For a very long time, nearly everything we knew about the stomach was thanks to an unfortunate accident in 1822. In the summer of that year, on Mackinac Island in Lake Huron in upper Michigan, a customer was examining a rifle in the island general store when it suddenly went off. A young Canadian fur trapper named Alexis St. Martin had the misfortune to be standing just three feet away and directly in the line of fire.*2 The shot tore a hole in his chest just below the left breast and gave him something he really didn’t want: the most famous stomach in medical history. St. Martin miraculously survived, but the wound never entirely healed. His doctor, a U.S. Army surgeon named William Beaumont, realized that the inch-wide hole gave him an unusual window into the trapper’s interior and direct access to his stomach. He took St. Martin into his home and looked after him, but with the understanding (sealed with a formal contract) that Beaumont would be free to perform experiments on his guest. For Beaumont, this was a peerless opportunity. In 1822, no one knew quite what happened to food once it disappeared down one’s throat. St. Martin had the only stomach on Earth that could be studied directly.
Beaumont’s experiments principally consisted in suspending different foods on lengths of silken thread into St. Martin’s stomach, leaving them for a measured interval, then pulling them out to see what had happened. Sometimes, in the interests of science, he tasted the contents to judge their tartness and acidity, and by so doing deduced that the principal digestive agent of the stomach is hydrochloric acid. This was a breakthrough that caused great excitement in gastric circles and made Beaumont famous.
St. Martin was not the most cooperative of subjects. Often he disappeared, once for four years before Beaumont was able to track him down. Despite these interruptions, Beaumont eventually published a landmark book, Experiments and Observations on the Gastric Juice and the Physiology of Digestion. For about a century, almost all medical knowledge of the process of digestion was thanks to St. Martin’s stomach.
Ironically, St. Martin outlived Beaumont by twenty-seven years. After drifting around for a few years, he returned to his hometown of St. Thomas, Quebec, married, raised a family of six children, and died aged eighty-six in 1880, nearly sixty years after the accident that made him famous.
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The heart of the digestive tract is the small intestine, twenty-five feet or so of coiled tubing where most of the body’s digestion takes place. The small intestine is traditionally divided into three sections: the duodenum (meaning “twelve,” because that is how many finger widths of space it was deemed to take up in the average man in ancient Rome); the jejunum (meaning “without food” because the jejunum was often found to be empty in corpses); and the ileum (meaning “groin” on account of its proximity to same). In fact, however, the divisions are entirely notional. If you took your intestines out and laid them on the ground, you wouldn’t be able to tell where one part began and the other ended.