An ideal system for new pathogens

EVERY DAY IN THE United States, roughly 200,000 people are sickened by a foodborne disease, 900 are hospitalized, and fourteen die. According to the Centers for Disease Control and Prevention (CDC), more than a quarter of the American population suffers a bout of food poisoning each year. Most of these cases are never reported to authorities or properly diagnosed. The widespread outbreaks that are detected and identified represent a small fraction of the number that actually occurs. And there is strong evidence not only that the incidence of food‑related illness has risen in the past few decades, but also that the lasting health consequences of such illnesses are far more serious than was previously believed. The acute phase of a food poisoning – the initial few days of diarrhea and gastrointestinal upset – in many cases may simply be the most obvious manifestation of an infectious disease. Recent studies have found that many foodborne pathogens can precipitate long‑term ailments, such as heart disease, inflammatory bowel disease, neurological problems, autoimmune disorders, and kidney damage.

Although the rise in foodborne illnesses has been caused by many complex factors, much of the increase can be attributed to recent changes in how American food is produced. Robert V. Tauxe, head of the Foodborne and Diarrheal Diseases Branch at the CDC, believes that entirely new kinds of outbreaks are now occurring. A generation ago, the typical outbreak of food poisoning involved a church supper, a family picnic, a wedding reception. Improper food handling or storage would cause a small group of people in one local area to get sick. Such traditional outbreaks still take place. But the nation’s industrialized and centralized system of food processing has created a whole new sort of outbreak, one that can potentially sicken millions of people. Today a cluster of illnesses in one small town may stem from bad potato salad at a school barbecue – or it may be the first sign of an outbreak that extends statewide, nationwide, or even overseas.

Much like the human immunodeficiency virus (HIV) responsible for causing AIDS, the E. coli 0157:H7 bacterium is a newly emerged pathogen whose spread has been facilitated by recent social and technological changes. E. coli 0157:H7 was first isolated in 1982; HIV was discovered the following year. People who are infected with HIV can appear healthy for years, while cattle infected with E. coli 0157:H7 show few signs of illness. Although cases of AIDS date back at least to the late 1950s, the disease did not reach epidemic proportions in the United States until increased air travel and sexual promiscuity helped transmit the virus far and wide. E. coli 0157:H7 was most likely responsible for some human illnesses thirty or forty years ago. But the rise of huge feedlots, slaughterhouses, and hamburger grinders seems to have provided the means for this pathogen to become widely dispersed in the nation’s food supply. American meat production has never before been so centralized: thirteen large packinghouses now slaughter most of the beef consumed in the United States. The meatpacking system that arose to supply the nation’s fast food chains – an industry molded to serve their needs, to provide massive amounts of uniform ground beef so that all of McDonald’s hamburgers would taste the same – has proved to be an extremely efficient system for spreading disease.

Although E. coli 0157:H7 has received a good deal of public attention, over the past two decades scientists have discovered more than a dozen other new foodborne pathogens, including Campylobacter jejuni, Cryptosporidium parvum, Cyclospora cayetanensis, Listeria monocytogenes , and Norwalk‑like viruses. The CDC estimates that more than three‑quarters of the food‑related illnesses and deaths in the United States are caused by infectious agents that have not yet been identified. While medical researchers have gained important insights into the links between modern food processing and the spread of dangerous diseases, the nation’s leading agribusiness firms have resolutely opposed any further regulation of their food safety practices. For years the large meatpacking companies have managed to avoid the sort of liability routinely imposed on the manufacturers of most consumer products. Today the U.S. government can demand the nationwide recall of defective softball bats, sneakers, stuffed animals, and foam‑rubber toy cows. But it cannot order a meatpacking company to remove contaminated, potentially lethal ground beef from fast food kitchens and supermarket shelves. The unusual power of the large meatpacking firms has been sustained by their close ties and sizable donations to Republican members of Congress. It has also been made possible by a widespread lack of awareness about how many Americans suffer from food poisoning every year and how these illnesses actually spread.

The newly recognized foodborne pathogens tend to be carried and shed by apparently healthy animals. Food tainted by these organisms has most likely come in contact with an infected animal’s stomach contents or manure, during slaughter or subsequent processing. A nationwide study published by the USDA in 1996 found that 7.5 percent of the ground beef samples taken at processing plants were contaminated with Salmonella , 11.7 percent were contaminated with Listeria monocytogenes , 30 percent were contaminated with Staphylococcus aureus , and 53.3 percent were contaminated with Clostridium perfringens . All of these pathogens can make people sick; food poisoning caused by Listeria generally requires hospitalization and proves fatal in about one out of every five cases. In the USDA study 78.6 percent of the ground beef contained microbes that are spread primarily by fecal material. The medical literature on the causes of food poisoning is full of euphemisms and dry scientific terms: coliform levels, aerobic plate counts, sorbitol, MacConkey agar, and so on. Behind them lies a simple explanation for why eating a hamburger can now make you seriously ill: There is shit in the meat.