Safe Food_ Bacteria, Biotechnology, and Bioterrorism - Marion Nestle [26]
To establish a basis for understanding the significance of such a profound shift in attitudes, this chapter begins with an introduction to the current status of microbial pathogens in the food supply. We will see that foodborne illness is more than a biological problem; it is strongly affected by the interests of stakeholders in the food system—the food industry, government (agencies, Congress, and the White House), and consumers. The present system of food safety oversight and its political implications are best understood in historical context. Thus, this chapter describes the origins of the century-old policies that govern federal actions to this day. In the case of meat safety, Congress designed those policies to prevent sick animals—not microscopic pathogens—from entering the food supply. As this chapter explains, efforts to modernize such policies do not come easily.
MICROBES IN FOOD: FRIENDS AND FOES
Thinking too much about the life we share with microbes can lead to paranoia. Microbes are everywhere: around us, on us, and in us. They inhabit soil and water, skin and digestive tract, and any place that provides favorable conditions for growth (and hardly any place does not). They are incredibly small, and incredibly numerous. All kinds—viruses, bacteria, protozoa, and yeasts—are ubiquitous in raw foods. Most are harmless. Some are even “friendly,” helping to make bread, wine, vinegar, soy sauce, yogurt, and cheese, and keeping our digestive tracts healthy. Others are less helpful; left to their own devices, they rot apples, mold bread, and spoil meat. Some are decidedly unfriendly, and cause more than 200 known foodborne diseases.
To avoid getting food poisoning, we take precautions: we preserve foods and we cook them. Preservation methods—some ancient, some modern (among them salt, sugar, alcohol, acid, and freeze-drying)—all inhibit microbial growth. Refrigeration slows down growth, and freezing does so even more. Cooking, a brilliant invention, not only makes foods taste better but also kills microbial pathogens. Cooked foods, however, do not remain sterile. Microbes in air, water, and other foods can recontaminate them, as can microbes on packages, plates, utensils, cutting boards, and hands. With common measures such as hand washing, dish washing, and other such basic precautions, we live with most food microbes in relative peace. Our digestive and immune systems take care of those that survive cooking. Mostly, we do not worry much about them.
TABLE 3. The most frequent microbial causes of foodborne disease in the United States: estimated numbers of illnesses, hospitalizations, and deaths, 1999
SOURCE: Mead PS, Slutsker L, Dietz V, et al. Emerging Infectious Diseases 1999;5:607–625.
NOTE: Illnesses generally include some form of gastrointestinal distress—diarrhea, vomiting, cramps—as well as the problems indicated. These figures continue to constitute the basis of prevalence estimates.
Whether we should worry more about them is a matter of how we perceive risk. For most of us as individuals, an occasional episode of stomach upset—if not too severe—is tolerable. From a public health standpoint, however, the cost to society of such episodes is staggeringly high. Table 3 lists, for example, the most frequent causes of foodborne disease, along with estimates of their cost in illness, hospitalization, and death. Viruses cause most foodborne illnesses, but some bacteria and protozoa are also to blame. Nearly all induce highly unpleasant symptoms, usually mild but sometimes very severe. Table 3, however, lists only the best-known