HEALTH & SCIENCE
American Medical News
March 19, 2007
Tackling tainted food: A lot can go wrong -- at any step along the way
Diagnosing a foodborne illness is straightforward. Determining where and when
the pathogen started may be more challenging.
By Victoria Stagg Elliott, AMNews staff. March 19, 2007.
Last fall, Dr. Samiya Razzaq, a pediatrician at Arkansas Children's Hospital in
Little Rock, witnessed the result of gaps in the nation's food safety controls.
Three young children were sick enough to be transferred to her institution
because of something they ate. Another 40 from the same day care center also
were ill, although they did not have to be hospitalized.
"The whole food safety system is fragile," said Dr. Razzaq, who also teaches at
the
University of Arkansas for Medical Sciences. "One little mistake from somewhere
and it's a major epidemic."
The good news is that these patients recovered. But the cause of this illness
cluster has not been confirmed, and Dr. Razzaq suspects it may have been part
of the large national outbreak of Escherichia coli O157:H7 reported in September
2006 and associated with raw, bagged, pre-washed spinach. At least 204 cases
were confirmed across the country, including three deaths.
Foodborne illnesses have made headlines in the past six months with stories
ranging from Salmonella-contaminated peanut butter to Clostridium botulinumtainted baby food. The Centers for Disease Control and Prevention estimate that
76 million illnesses annually can be blamed on foodborne pathogens. And each
year, 325,000 people are hospitalized; 5,000 do not survive.
Ironically, it is produce -- usually considered to be among the healthiest of foods - that has been associated with much of the recent harm. The latest report from
the CDC's Foodborne Diseases Active Surveillance Network says food-related
illnesses have declined over the past decade, and many experts say the food
supply is more safe than ever. But produce seems to be responsible for a
growing percentage
of these incidents, with bagged salad blamed most often. According to the Center
for Science in the Public Interest, salads are the culprit in 28% of produce-related
outbreaks.
"We live in a microbial world. If something has crawled or slithered or flown
over that field and defecated, there's really little we can do to
decontaminate that piece of produce," said Sam Beattie, PhD, assistant
professor in food science and human nutrition at Iowa State University in
Ames.
To be fair, detection of recent widespread outbreaks in part can be attributed to
improved public health technology and industry trace-back systems. The
development of pulsed field gel electrophoresis means that bacteria can be
distinguished at the
DNA level, and the establishment of CDC's PulseNet just over a decade ago
allows public health and food regulatory agency laboratories to match up these
bacterial "fingerprints."
"A patient in Ohio, somebody else in Florida, someone else in Long Island might
have gone unrecognized before," said Marguerite Neill, MD, associate professor
of medicine at Brown Medical School and an infectious disease physician at
Memorial Hospital of Rhode Island in Pawtucket.
But factors other than detection bias are probably at work, too, experts say. For
instance, E. coli O157:H7, which was discovered only decades ago, has proven
to be more virulent than many other pathogens. Washing will reduce its
presence, but even nearly undetectable amounts are dangerous.
Changes in how food is produced and eaten also may play a role. Food is more
likely to be mass-produced and distributed widely rather than being grown and
eaten locally, making contamination during the production process a national,
even international, problem. The most recent spinach outbreak hit people in 26
states and Canada.
"When your food came from the farm down the street, people got sick, but the
number of people made ill was small," said Bennett Lorber, MD, Thomas M.
Durant Professor of Medicine in the infectious diseases section at Temple
University School of Medicine in Philadelphia. "Now we have immense food
producers, producing incredible volumes of food, and it's distributed all over
country. If there's a contamination problem, there's the potential for many, many
people to be sick."
Consumers also are eating more produce, particularly if it has been cut and
washed before being packaged. According to the U.S. Dept. of Agriculture, per
capita consumption of fresh spinach in 1980 was less than half a pound per
person. It increased to more than a pound and a half in 2003. Much of this
growth is due to increases in sales of triple-washed, ready-to-eat bagged
spinach.
While such products make it easier to eat these generally healthy foods, it also
appears to present more possibilities for contamination as spinach makes its way
from the farm to the dinner table.
"Not a controlled environment"
The leading candidate for last fall's spinach-related outbreak is feces from cattle
at bordering ranches or from wild pigs who wandered through fields, but the
irrigation water or the wash used in processing could have been tainted. The
problem could have been fertilizer. Cutting the vegetable in the fields may make
a ripe environment for bacteria to flourish. Those who picked, processed and
packaged it may not have had good hygiene.
"A farm is outside. It's not a controlled environment," said Don Schaffner, PhD, a
spokesman for the Institute of Food Technologists, an international nonprofit of
22,000 food scientists. "You can't control the rainfall. You can train people to
wash their hands, but cows and pigs cannot be as easily trained. And heaven
help us if the problem comes from birds."
Packaging may be conducive to bacterial growth, although this is unproven. The
product may have been improperly stored in transport, the grocery store or the
consumer's home. Once the vegetable is out of the package, it could be
mishandled.
Although farming and processing issues are getting attention right now,
consumer mishandling remains the most common cause of foodborne illness.
"Somebody makes some hamburgers. Then they use the same cutting board and
cut up some spinach for spinach salad, and there's cross-contamination," said
Jeffrey T. LeJeune, DVM, PhD, who teaches in the food animal health research
program at
Ohio State University.
While the actual reason for last fall's outbreak is unclear, government and
industry
stakeholders are taking action. In January, the large fresh-cut salad producer
Fresh Express, whose products were not associated with the illness, said it
would provide $2 million for research leading to strategies that would prevent E.
coli contamination.
Also, last month, more than 90% of companies in this industry signed the
California Leafy Greens Marketing Agreement requiring signatories to follow
guidelines governing irrigation water quality, purity and timing of fertilizer,
harvesting equipment cleaning, and farm worker behavior.
"Food safety is a sacred trust between the people in our industry and the public,"
said Tom Nassif, president and CEO of Western Growers, an agriculture trade
group in Irvine, Calif. "We take that responsibility extremely seriously."
Meanwhile, the Food and Drug Administration added spinach to its Lettuce
Safety Initiative and will hold a public meeting this year on foodborne illness
associated with greens. The agency also will consider if more guidance or
regulation is necessary or if irradiation of these products should be allowed.
The USDA is funding research to assess the presence of E. coli to determine its
sources and look for strategies to reduce it. The Government Accountability
Office called transforming food safety a high-risk issue in January and wants the
structure of the system, currently run by 15 federal agencies, to be reconsidered.
"There ought to be a government-wide approach to food safety," said Lisa
Shames, GAO acting director of food and agriculture issues. "It's not that food is
unsafe. It's just that the system is fragmented."
Can physicians do more?
Food safety issues also maintain a high profile among physician concerns. The
American Medical Association published Diagnosis and Management of
Foodborne Illnesses: A Primer for Physicians and Other Health Care
Professionals, in conjunction with the American Nurses Assn., the CDC, the
FDA's Center for Food Safety and Applied Nutrition and the USDA's Food Safety
and Inspection Service in April 2004.
But food safety experts want more. Those working in this area want physicians to
step up testing to determine exactly what is causing a patient's illness to make
outbreak detection easier. Knowing that can affect treatment decisions because,
in the case of E. coli O157:H7, evidence suggests that antibiotic use can make
things worse.
"A lot of time physicians will tell people, 'Oh, it's food poisoning.' But they'll never
order a stool culture," said Dr. Schaffner of the food technologists group. "I know
physicians are limited by insurance, but it would really be wonderful for
physicians to work with us more closely."
Physicians say this is not always practical. Millions may be affected by foodborne
illness, but only a fraction are sick enough to see a doctor. Because there is no
rapid in-office test, an even smaller percentage will still be sick when results
come in.
For example, Richard Roberts, MD, a family physician in Belleville, Wis., treated
a 70-year-old man in August 2006. The man had severe diarrhea and may have
been a part of the spinach outbreak. He collected stool cultures, because the
man's age put him at greater risk for severe illness. The test results came back
days later as positive
for E. coli O157:H7. By then, though, the man was well.
"The problem with getting cultures most of the time is that by the time you get the
results back the person is better. Then you feel like you've wasted money," said
Dr. Roberts, former president of the American Academy of Family Physicians.
"You give me a test that I can do on the spot at a reasonable price and have the
results here in the clinic. I'll do that."
� Recognize that a foodborne contaminant may be making a patient sick.
� Realize that many illnesses resulting from food consumption, although not all,
have
gastrointestinal symptoms.
� Obtain stool cultures as appropriate.
� Request testing for some pathogens as necessary.
� Consider the possibility of intentional contamination.
� Report suspect cases to public health officials.
� Discuss with patients ways to prevent food-related disease.
� Acknowledge that the young, old, pregnant and those with compromised
immune
systems face greater risks from foodborne illnesses.
� Appreciate that any patient with a foodborne illness may represent the first clue
to a
more widespread outbreak.
Source: Diagnosis and management of foodborne illnesses: A primer for
physicians and
other health care professionals, February 2004