associated with starvation. According to the Food and Agriculture Organization of the United Nations (FAO), there were more than 820 million undernourished people in the world in 2006. On the one hand, after some gains were made in improving the food supply in the 1970s and 1980s, the human race seems, at best, to be barely holding on. On the other, morally and physically gross, hand, in industrialized regions of the world, people are dying from eating too much; if I were in my (non–politically correct) veterinary frame of mind, I would say these people are fat and are dying from being fat, all the while complaining that the airplane seats are too small and the fast food has the wrong kinds of fat in it. The World Health Organization estimates that a billion adults worldwide are overweight and 300 million of them are clinically obese.
So all in all, the diseases described in this book are not catastrophic. Nevertheless, there are risks. In 2006, the week before my class lecture on E. coli, there was an outbreak of E. coli from spinach. The week before my lecture on botulism, half a dozen people were in hospitals across North America because they had chugged back all-natural carrot juice laced with all-natural botulism toxin. The week before my lecture on foodborne viruses, a couple of hundred students at a Canadian university ran for the stalls down the hall as part of an outbreak of Norwalk-like virus. My friends at the Public Health Agency of Canada were consulting my syllabus to see what illness they should prepare for next.
There is strong scientific evidence that the rates of foodborne disease in industrialized countries have been increasing as the result of global warming in the 1990s and into the twenty-first century; the patterns of those diseases have also been altered by trade, cultural, political, and environmental changes which I shall discuss in this book. The industrial methods developed to control foodborne diseases are, at best, pushing the rates down slightly for some diseases, but overall keeping them in a holding pattern. These diseases are not going away, and consumers (at last, a context in which it makes sense to describe people as consumers) should educate themselves about them, learn from them, and seek ways to reduce them. For me, the most convincing reason to pay attention to foodborne diseases is that they are part of our most intimate lifelong relationship. These diseases tell us as much about our complex relationships with the planet as STDs tell us about our contradictory relationships with each other. I have as much fun thinking about food as I do about sex. I hope you do as well.
This book is about understanding intimacy, about self-fulfillment, about you and your food partners. The next time you take a forkful of meat or rice or peas, ponder for a moment the environment with which you are about to become intimate. You may find that you wish to ask a few questions of it. You may want to know if she is a local girl, or if she just flew in from some exploited foreign environment. You may suddenly find yourself interested in the agricultural practices of Mexico, Spain, California, British Columbia, and Ontario. Good. This interest in your life’s most intimate partner could be the start of something beautiful.
We may decide, like the good burghers of nineteenth-century Paris, that we do not wish to risk death for tasty bread. The following, quoted by noted microbiologist Theodor Rosebury in a wonderful, classic, must-read book, Life on Man, first appeared in “The Last Cholera Epidemic in Paris,” in the General Homeopathic Journal, vol. 113, p. 15 (1886):
The neighbours of the establishment famous for excellent bread, pastry, and similar products of luxury, complained again and again of the disgusting smells which prevailed therein and which penetrated into their dwellings. The appearance of cholera finally lent force to these complaints, and the sanitary inspectors who were sent to investigate the matter found that there was a connection between the water-closets of those dwellings and the reservoir containing water used in the preparation of the bread. The connection was cut off at once, but the immediate result thereof was a perceptible deterioration of the quality of the bread. Chemists have evidently no difficulty in demonstrating that water impregnated with “extract of water closet” has the peculiar property of causing dough to rise particularly fine, thereby imparting to bread the nice appearance and pleasant flavor which is the principal quality of luxurious bread.
Or we may, like many modern Japanese (and a few California chefs), decide that the risk of instant death that may come from an improperly cleaned puffer fish or the hole bored in one’s stomach by Anasakid worms from parasitized salmon only adds spice to the delicate temptations of the flesh.
What is important is to know that we have choices, and that we own those choices, and to make them intelligently. The unexamined food, I would say, if I may be so bold as to take some license with Aristotle, is a risk not worth eating.
2 THE VOICE OF THE UNSEEN GUEST
WHEN ANTON van Leeuwenhoek looked down his crude microscope in 1674 and discovered a world of “very little animalcules,” he did not imagine that whole populations of these tiny creatures attended our every meal and entered our bodies unheralded. Or that there might be even smaller beasties, the viruses, inside the tiny bacteria he was seeing. Nor did those devout families who set out an extra chair for the Unseen Guest at their meals imagine that they were surrounded by millions of unseen guests who had no need of chairs.
Wading into the orgiastic world of microbes can be disconcerting. Why would any morally upright God create such an amoral mess of living things, breeding and crossbreeding, exchanging genetic material without regard for race, creed, species, or sexual preference? Right under our noses? Right in our noses? I am not a theologian, and cannot understand this, but we shall probably have to pinch our moral noses as we explore this world in order to rescue the maiden of our amazing and improbable lives.
When these microscopic bacteria and viruses enter our maws, riding on eggs and hamburgers as children in an amusement park might ride into a tunnel of ghosts, with what voices do they scream their joy and terror? How, in short, do they make us sick?
One might say that contaminants in our food can make us sick in one of two ways: through intoxication or through infection. Intoxications, caused by toxins in food, occur within minutes to hours after eating and are most often associated with vomiting. These are, technically, what we can call food poisoning. Infections, which require time for bacteria from the food to multiply inside the host’s body before they cause havoc, develop hours and even days or weeks after eating, and the main sign is diarrhea. This would be called a foodborne infection. “Foodborne disease” covers both intoxications and infections.
Vomiting and diarrhea are the two most common characteristics of foodborne disease. I refer to them as “signs,” which should be differentiated from “symptoms.” Although many other writers are less careful in their use of these words than I am, the distinction is useful. A sign is what can be seen and measured in some way, like temperature, pulse, and the amount of water in your stool. A symptom is something you feel, like pain, a headache, or tingling in your fingertips. The distinction is obviously useful for a veterinarian, but it is also important for people. A doctor can (at least theoretically) measure a sign, even if the patient is a young child; you have to tell the physician about your symptoms. Most diseases present as a mixture of signs and symptoms.
If we call diarrhea a sign, which I would, you might well ask how we can measure it. Diarrhea occurs when a person’s feces have increased water content above what we normally expect; not to put too fine a point on it, the feces flow, rather than plop. One could, of course, measure exact water content of a stool, but the simplest definition of diarrheic stool is that it takes the shape of the container into which it is put. Public health officials then usually say that a person has diarrhea if he or she has two or more (or occasionally three or more) such stools in a twenty-four-hour period.
Vomiting, also called emesis, occurs when your abdominal muscles and diaphragm contract, throwing the contents of the stomach and upper small intestine up through your esophagus and mouth (and, if you are really unlucky, your nose). Vomiting is controlled by a certain part of the brain, which is excited when it receives messages from certain nerves, many of which have endings in the stomach and upper small intestine.