Progress toward reducing
infections from some pathogens has hit a plateau, indicating
"fundamental problems with bacterial and parasitic contamination are
not being resolved," a recent report states.
The Centers for Disease
Control and Prevention released a Morbidity and Mortality Weekly Report
April 10 indicating the prevalence of illnesses from nine foodborne
pathogens has declined since the 1990s but remained level from 2004 through
2008. The report is available at www.cdc.gov/mmwr/preview/mmwrhtml/mm5813a2.htm.
Those pathogens are Campylobacter, Cryptosporidium, Cyclospora, Listeria, Shiga
coli (STEC) O157, Salmonella,
Shigella, Vibrio, and Yersinia.
The data are based on
surveillance through FoodNet, which has monitored laboratory-confirmed
infection data since 1996. The surveillance population is about 46 million
people, and in that population were about 18,500 laboratory-confirmed cases
in 2008 of infection with the nine previously listed pathogens.
The report notes none of
the 2008 goals for reduction of foodborne pathogens were met under Healthy
People 2010, an initiative launched by the Department of Health and Human
Services in January 2000 to promote health and prevent disease. The
initiative has 28 focus areas covering a broad range of human health
issues, including food safety.
The Salmonella infection
rate, at 16.2 cases per 100,000 people, is furthest from the Healthy People
2010 initiative goal of 6.8 per 100,000.
"The lack of recent
progress toward the national health objective targets and the occurrence of
large multistate outbreaks point to gaps in the current food safety system
and the need to continue to develop and evaluate food safety practices as
food moves from the farm to the table," the report states.
The CDC did not compile data that would indicate whether safety had
improved among food animals or plants, spokeswoman Lola Russell said. The
agency is recommending that actions be taken, and it is up to food safety
regulators to decide how to respond.
Dr. John R. Dunn,
director of Foodborne, Vectorborne, and Zoonotic Diseases for the Tennessee
Department of Health and principal investigator for FoodNet in Tennessee,
said better communication and partnership across public health and regulatory
agencies could improve understanding of sources of food contamination and
subsequent outbreaks. He noted an increase in the number of illnesses
associated with produce in recent years.
"Many of these
foodborne pathogens have some connection to an animal reservoir," Dr.
David Goldman, MD,
assistant administrator for the Department of Agriculture's Food Safety and
Inspection Service, said a Salmonella
initiative started by his agency in 2006 has substantially reduced the
bacteria's presence in raw meat and poultry products.
"We have worked hard
to reduce contamination in FSIS-regulated products and have seen marked
success in Salmonella
monocytogenes," Goldman said. "We are concerned about
the lack of progress in reducing the incidence of foodborne illness and
believe this report points to the need for better information about sources
David Acheson, MD,
associate commissioner for foods at the Food and Drug Administration, sees
a shift in the foods that have been associated with foodborne illness.
"We've seen a number
of foods associated with outbreaks that we haven't seen before," Dr.
Acheson said. "Peanut butter is a classic one where we've seen two big
outbreaks in the last couple of years, which has never happened before in
the United States."
Dr. Acheson noted
jalapeño peppers, which were associated with a Salmonella outbreak in summer 2008, are
also a new vehicle for illness.
Investigators are better
at finding foodborne pathogens and their sources, Dr. Acheson said, but it
was not clear if that fully explained why pathogens have recently been
associated with different foods.
"It's hard to know
whether we're just getting better at it or whether the landscape is
changing," Dr. Acheson said. "It may be a combination of the
Dr. John P. Sanders,
branch chief for food defense and preparedness coordination in the
Department of Homeland Security's Office of Health Affairs, said the CDC
has received more outbreak reports since switching from paper reports to
the electronic Foodborne Outbreak Reporting System in 2001. The technology
used to identify foodborne pathogens has also improved, and public
awareness has increased.
Dr. Acheson noted some
initial gains in food safety after FoodNet was started in 1996, and he agreed
with the assessment that infection rates have leveled off among the major
pathogens tracked through the service.
"What I take from
that is we need a new approach," Dr. Acheson said. "We have got
to be looking at learning from the controls that we've put in place—the
systems we've put in place—because, obviously, there's been some effect
from that, but it's no longer driving (rates) down further."
Dr. Acheson said cleanup
of food processing equipment between runs of raw and roasted pistachios
could have prevented contamination at a California factory. Though the
factory was associated only with a recall and not an outbreak, he said the
facility is useful as an example for control of food contamination.
It is likely that, as new
measures are implemented, food safety will again plateau, Dr. Acheson said.
"But if you're on a
winning streak here, you're going to plateau lower, and then you'll
identify the next round of controls that you need to put in place, and you
plateau even lower," he said.
the "low-hanging fruit"
Dr. David R. Smith, a professor and extension dairy and beef veterinarian
for the University of Nebraska, said the reductions in foodborne illnesses
prior to 2004 coincided with safety improvements in postharvest sectors of
animal industries, particularly those related to beef cattle. The FoodNet
data suggest to him that members of the animal agriculture industry have
adopted some of the easiest measures to improve safety.
fruit has been picked, and it's time to look at where else are there gaps
in food and environmental safety," Dr. Smith said.
For example, Dr. Smith
said little has been done to reduce carriage of E coli O157 or Salmonella in live
cattle, which could also reduce environmental contamination of produce.
Veterinarians and the
veterinary profession can also work to increase public awareness of the
risks posed by zoonotic pathogens, Dr. Smith said.
Dr. Sanders said
outbreaks of foodborne illness involving produce still tend to involve
human or animal contamination of crops or irrigation water, and he cited as
an example an E coli
0157:H7 outbreak associated with feral swine crossing a spinach field.
"Salmonellosis is a large proportion of our foodborne disease illness,
so in that respect it's disappointing that we're not able to identify
things that would create a sustained decline."
Dr. Sanders said such
outbreaks have raised the awareness of Congress, and that could increase
opportunities for veterinarians in public practice.
"Hopefully we will
get some additional funding for the agencies that are involved in food
safety, where this is an opportunity for them to become involved," Dr.
Though the FoodNet data
do not indicate which food has become contaminated, they provide insight
into the volume of illnesses in the United States. Dr. Acheson likened
FoodNet reports to report cards and said they are valuable for regulatory
Some changes are evident
in the incidence of pathogens, as seen in a substantial decline in E coli O157-related
illnesses several years ago, Dr. Dunn said. The incidence has not
substantially declined since, and opportunities exist for veterinarians
interested in research related to the bacteria and food safety.
integration of veterinarians at all levels of food safety—from the
preharvest aspects that I mentioned all the way through to the end that I
work on, which is the identification of illness and
investigation—veterinarians have contributed greatly, and there's ample
opportunity to continue to address this problem of foodborne illness for
veterinarians," Dr. Dunn said.
with public health and livestock can serve as consultants for farms and
feedlots and minimize the impacts they have on surrounding produce farms,
Dr. Sanders said. The FDA has been working with Cornell University and the
University of Maryland on the Good Agricultural Practices program to
educate farmers about their impact on food safety.
The DHS, USDA, and FDA
are also working to improve abilities to detect harmful agents in food, Dr.
Sanders said. The DHS is also working with state and local health
departments to help them stabilize their funding and focus on food
Dr. Dunn said that,
despite improved ability to measure incidence of Salmonella since the
advent of FoodNet, the data do not show a sustained decline in
"Salmonellosis is a
large proportion of our foodborne disease illness, so in that respect it's
disappointing that we're not able to identify things that would create a
sustained decline, particularly in salmonellosis," Dr. Dunn said.
A CDC report from April
2005 indicates substantial declines from 1996-2004 in the estimated
incidence of infections with Campylobacter,
STEC O157, Listeria,
serovar Typhimurium, and Yersinia.
Similar to the 2009 report, the 2005 report called for efforts to
understand and control pathogens in animals and plants, reduce or prevent
contamination during processing, and educate consumers. The CDC posts an
annual summary report on the FoodNet surveillance, and as of press time,
the last full report available online involved data from 2004.
– Greg Cima