Unwelcome Table Guests
Here’s how to keep your food safe and protect
yourself from E. Coli and other undesirables
By Linda Melone
Fresh cantaloupe, organic spinach, cheese and milk—nutritious parts of a healthy diet—have all been implicated as sources of foodborne illnesses. Each outbreak brings renewed concern over the safety of our food, and with good reason. One recent outbreak involved Colorado melons infected with the bacteria Listeria monocytogenes, an occurrence that the US Centers for Disease Control and Prevention (CDC) calls one of the deadliest in nearly 90 years. The infected cantaloupes claimed 29 lives.
Food poisoning symptoms vary by the specific pathogen but typically include diarrhea, vomiting and stomach cramps within 4 to 36 hours after eating contaminated food. Roughly one in six, or 48 million, people in the US gets sick each year, 128,000 are hospitalized and 3,000 die of foodborne diseases, according to the CDC.
Ongoing problems with food contamination occur in spite of great strides that have been made in reducing the incidence of particularly dangerous bugs, such the harmful strains of Escherichia coli. The incidence of infections from E. coli, responsible for the recall of millions of pounds of ground beef, has been reduced by half during the past 15 years. But at the same time, Salmonella infections remain unchanged, causing more deaths and hospitalizations than any other foodborne germ.
Healthy Eating Hazards
Ironically, people’s desire to eat fresh produce instead of canned and other processed foods contributes to the contamination problem. “Our desire to eat healthier may be part of the reason for the increased incidences of foodborne pathogens over the past decade,” says Jason Tetro, BSc, a microbiologist at the University of Ottawa’s Centre for Research on Environmental Microbiology.
The increased importation of fruits and vegetables into the United States, as well as higher levels of meat production in which animals are raised in confined, small spaces contaminated with manure and urine, all contribute to food that is less safe, Tetro says. “The demand for more fruits and vegetables in the diet has left trade openings now being filled by countries that may not have the same food safety standards as in America,” he says. “Growing locally is perhaps the best way to ensure that the levels of food safety are kept high.”
Imported fruits and vegetables requires additional handling along a lengthened supply route. As a result, imported produce undergoes greater exposure to increased moisture and temperature conditions, all of which help bacteria grow.
The demand for more food, Tetro adds, also brings more waste, which in turn brings more risk and which also finds its way back into our food. “It’s a continuous cyclic ecology,” Tetro says. Plus, meat production using concentrated animal feeding operations makes it impossible to maintain top cleanliness. “As a result, the use of antibiotics is considered mandatory for many establishments, in order to keep the animals from getting sick,” he says. Over time the bacteria (Campylobacterjejuni, E. coli O157:H7, Clostridium difficile and Yersinia entercolitica, among others) develop resistance to these antibiotics; the bacteria then find their way into the food supply.
Although the last decade has seen more consumer awareness about safety risks associated with food, we are not always translating that awareness into practical everyday action, says Heli Perrett, PhD, sociologist, microbiologist and author of The Safe Food Handbook: How to Make Smart Choices About Risky Food (The Experiment LLC). “In fact, our increasing reliance on imported foods and ready-to-eat [convenience] foods is part of the continuing problem.”
Unfortunately, eating an organic diet may not necessarily decrease your risk of suffering a foodborne illness. “While organic is certainly likely to carry fewer pesticides, hormones and antibiotic residues versus food grown conventionally,” Perrett says, “it is just as likely to carry bacteria, viruses and toxic molds.”
The widespread use of antibiotics on the farm has also contributed to the problem, says Michael G. Schmidt, PhD, professor of microbiology and immunology at the Medical University of South Carolina. “‘Farm-to-table’ is the phrase, and antibiotics are a way to reduce the time for this process. Such selective pressure has increased multi-drug resistant microbes.”
The Biggest Dangers
Some pathogens are more dangerous to some people than others, depending on the person’s age and health. The high-risk group includes pregnant women, those with weakened immune systems or serious medical conditions such as kidney disease or diabetes, and people over age 65. “For pregnant women, L. monocytogenes and certain toxic chemicals such as PCBs and dioxins, and the metal mercury, are the most important hazards to avoid in food,” says Perrett.
In some cases, pathogens found in one type of food have cropped up in others. For example, E. coli, a bacteria generally found in undercooked hamburger, can appear in produce as well as in protein, says Shelley Feist, executive director of the Partnership for Food Safety Education, a food safety and health education group in Washington, DC (www.fightbac.org). These incidences are not new, however, but we have a greater awareness of them, says Feist. “This is primarily due to an improved outbreak tracking system at the CDC, which makes it possible to learn more about what might be causing an outbreak.” Produce may become contaminated due to exposure to contaminated water, improper use of animal waste/manure on fields, or improper handling of the produce at various points in the food chain.
Salmonella, however, remains one of the most common bacteria and results in the greatest number of hospitalizations, although it’s not usually deadly,” says Feist. Another E. coli incident in 2009 involved cookie dough: Eating bits of raw, prepackaged cookie dough (Nestlé brand) sickened 65 people in 29 states, 25 of whom required hospitalization, according to the CDC.
L. monocytogenes, on the other hand, is less common. But this bacteria can be deadly, causing an infection called listeriosis capable of spreading beyond the gastrointestinal tract. Listeria can continue to grow at the kinds of cold refrigerator temperatures that typically inhibit the growth of other pathogens. Heat kills it but if the heated food cools, the bacteria may grow again.
“Among the viruses, Norovirus is the most common, and tends to turn up in places such as cruises, receptions, institutional dining rooms,” says Perrett. “It is very contagious but not as deadly as some of the bacteria.”
The most deadly natural toxins are those found in seafood and in mushrooms, says Perrett. “Of the two, the natural toxins in seafood are of most concern.” Scrombroid poisoning results from eating spoiled fish and is second to ciguatera poisoning, the most common type of fish-borne poisoning in the US. Ciguatera poisoning develops from eating reef fish that feed on a marine microalgae called Gambierdiscus toxicus.
Other types of food poisoning take time to take effect and result in much longer-term health issues.
“When people talk about food poisoning they’re usually referring to a bug of some sort,” says Tetro. “Unless it’s something serious like E. coli, most symptoms go away within a few days or a week. An exception is ‘bioaccumulation,’ which occurs without symptoms and has other, longer-lasting effects.” Bioaccumulation refers to a buildup of substances, such as pesticides, within the body. The accumulation of the toxic substance occurs at a rate greater than the ability of the body to remove it.
These toxins include arsenic, heavy metals, PAH (found in diesel exhaust, for example), dioxins (which are found in certain pesticides and industrial fluids), drugs and hormones, says Tetro.
“They’re persistent in the environment.” Fish normally have low levels of PCBs in their systems, but if you eat a lot of fish the chemical accumulates in your system. Mercury, too, is stored in adipose (fat) tissue, where it can build up. “It’s like death by paper cuts,” says Tetro. “One fish won’t kill you but continuing to eat it can lead to an unstable immune system. This may then contribute to diabetes, obesity and metabolic disorders.”
The accumulation of toxins such as diesel exhaust, arsenic and heavy metals affects the immune system and can lead to autoimmunities (diabetes, depression) and other complications such as metabolic disorders and cardiovascular issues.
Reducing your risk of contacting a foodborne illness comes down to basic hygiene in many cases, says Feist. Most importantly, wash your hands before handling food and rinse fresh produce under clean, running tap water before eating it, even if you’re not eating the rind. This avoids cross contamination with other foods.
Adds Perrett, “There are many risks in food that are simply beyond our control, no matter how careful we are, but food is to be enjoyed. We shouldn’t stress out about what we can’t control. But that doesn’t mean we shouldn’t take reasonable precautions. It does not have to involve much more time
or expense, and it will have a good payoff in terms of our energy level and health.”