Food Safety: Something to Chew On

From the WebMD Archives

May 21, 2001 -- From the time you wake up until you fall into bed, you engage in activities that can enhance your health or increase your risk for disease. But there is one activity so universally indulged in, so intimately tied to sustenance, and so directly related to health and illness, and it happens right under your nose -- quite literally: eating food.

But a lot of people get sick from eating food. An estimated 76 million cases of foodborne diseases occur each year in the U.S., according to the CDC.

"Food safety is an important public health issue for the simple reason that all of us consume food," says William Schaffner, MD, chair of preventive medicine at Vanderbilt University School of Medicine in Nashville, Tenn. "Everyone's grandmother knows that food can be a source of both nourishment and pleasure -- and can also make you sick."

The great majority of food poisonings are mild, causing symptoms for only a day or two. But some cases are more serious: CDC estimates there are 325,000 hospitalizations and 5,000 deaths related to foodborne diseases each year. The most severe cases tend to occur in the very old, the very young, those who have an illness that weakens their bodies' natural defense -- their immune system function -- and in healthy people exposed to a very high dose of a foodborne "bug," according to the CDC.

For these reasons, food safety and the effort to eradicate foodborne illness have for years been a focus of public health activity. And a number of frightening diseases that have emerged recently -- specifically the so-called mad cow disease -- have heightened concern about the safety or availability of food.

In this and related articles to come, WebMD will outline prominent food safety issues and concerns, highlight government and scientific efforts aimed at making food safe, and offer practical tips to help you prepare and serve food safely.

Food Safety: Not an Easy Task

Public health experts tell WebMD that one prominent feature of modern life -- global travel and commerce -- has made food safety exponentially more important and more difficult.

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"In a world where the borders are no longer well defined, how do you standardize regulations so that the food on our table is safe, even though it may come from parts of the world where standards vary?" says Karen Becker, DVM, of the Office of International and Refugee Health in the Department of Health and Human Services.

And it prompts one fundamental question: Can people reasonably expect the food they buy to be safe?

"The answer is both a resounding yes and a resounding no," says Schaffner. "There is no doubt that we in the U.S. enjoy the best record of food safety of any nation in the world. Despite this, our food is not perfectly safe -- and far from it."

And now, Schaffner says, because of international commerce there is an abundance of foods and vegetables available year-round that did not come from California, Texas, or Florida.

"They are coming from Mexico, South America, and Central America," he says. "That is one reason that food safety is back high on the agenda of public health."

Common Food Poisoning Culprits

So what are the prominent foodborne bugs that trigger illness?

The CDC says that the most commonly recognized food bugs are the bacteria Campylobacter, Salmonella , and E. coli. and a group of viruses known as Norwalk viruses.

  • Campylobacter causes fever, diarrhea, and abdominal cramps and is the most commonly identified bacterial cause of diarrheal illness in the world. These bacteria live in the intestines of healthy birds, and most raw poultry meat has Campylobacter on it. Eating undercooked chicken or other food that has been contaminated with juices dripping from raw chicken is the most frequent source of this infection.
  • Salmonella is widespread in the intestines of birds, reptiles, and mammals. The illness it causes, salmonellosis, typically includes fever, diarrhea, and abdominal cramps. In people with poor health or weakened immune systems, it can invade the bloodstream and cause life-threatening infections.
  • E.coli O157:H7 is a bacterial pathogen that has a reservoir in cattle and other similar animals. Human illness typically follows consumption of food or water that has been contaminated with microscopic amounts of cow feces. The illness it causes is often a severe and bloody diarrhea and painful abdominal cramps, without much fever. In 3-5% of cases, a complication called hemolytic uremic syndrome, or HUS, can occur several weeks after the initial symptoms. This severe complication includes low levels of iron called anemia, profuse bleeding, and kidney failure.
  • Norwalk virus is an extremely common cause of foodborne illness, resulting in vomiting that resolves within two days. Unlike many foodborne bugs that reside in animals, Norwalk-like viruses spread primarily from one infected person to another. Infected kitchen workers can contaminate a salad or sandwich as they prepare it, if they have the virus on their hands.

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Some common diseases also can be foodborne, even though they usually are transmitted other ways. These include infections caused by the bacteria Shigella -- the virus that causes hepatitis A -- and the organisms Giardia lamblia and cryptosporidia. Even cases of strep throat have been transmitted through food, according to the CDC.

During 1999, the CDC's Foodborne Diseases Active Surveillance Network, or FoodNet for short, identified almost 11,000 confirmed cases of just nine diseases under surveillance. Among those were more than 4,500 cases of salmonellosis, nearly 3,800 cases of campylobacteriosis, and 530 E. coli O157 infections.

FoodNet is the principal foodborne disease component of CDC's Emerging Infections Program and is a collaborative project of the CDC, the United States Department of Agriculture, the FDA, and nine state Emerging Infection Programs -- California, Colorado, Connecticut, Georgia, Maryland, Minnesota, New York, Oregon, and Tennessee.

New Technology Breeds New Concerns

But food bugs aren't the only food safety concerns. Advances in biotechnology have triggered new worries about food safety. Most prominent is the introduction of genetically engineered food, sometimes called "frankenfoods."

Frankenfoods are produced using modern genetic techniques that allow manufacturers and growers to modify the product's genetic material in ways not possible with traditional selective breeding. For example, researchers can transfer genetic material from one species to another, such as from animals to plants. The intent is to make the product grow better, faster, or bigger. A variety of genetically engineered plants are now under development, and some crops have reached the marketplace.

According to the Environmental Defense Fund, a major concern with modifying foods via genetic engineering is that they may cause some individuals to become allergic to foods they previously weren't allergic to. Food allergies affect an estimated 2.5 to 5 million Americans -- a serious, and sometimes life-threatening, public health concern.

In January, the FDA issued a proposed rule requiring makers of genetically engineered foods to notify the agency at least 120 days before the food is marketed. The agency also intends to list more information about each frankenfood it evaluates at a special Internet site -- http://www.cfsan.fda.gov/~lrd/biotechm.html.

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The Bottom Line

Although there is much that consumers, governments, and public health agencies can do to protect the food supply, foodborne illness is most often the unintended consequence of normal human activity and industry.

Schaffner provides the following illuminating example: Apples grown in an apple orchard are picked from a tree, but the ones that fall on the ground are used to make cider. If the apples fall in a field where cattle also defecate, the cider can be contaminated if it is not properly pasteurized.

So ultimately, public health officials view foodborne illness as something that will never be totally eradicated; at best, it can only be minimized.

"In public health, we don't talk about a safe food supply, but about reducing the risk and making the food safer," Schaffner tells WebMD. "We will never achieve perfect safety. We do have the safest food supply in the world, but it requires constant attention by the government, industry, and consumers."

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