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Research and Risk Assessment
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(Table of Contents)
Solidifying the Science Base
In FY 2000, food production technologies continued to advance rapidly, adding to
the Center for Food Safety and Applied Nutrition's (CFSAN) challenges as a guardian of the
public health responsible for ensuring a safe food supply. And in that fiscal year,
CFSAN continued its longstanding practice of collaborating with the external
scientific community to complement the core of
expertise within the agency. As a primary CFSAN strategy, leveraging has brought a wide range
of scientific thinking to bear on public health issues.
In FY 2000, FDA worked in cooperation with many partners _ in such federal and
state collaborations as the Joint Institute for
Food Safety Research (JIFSR) and the Risk Assessment Consortium (RAC), and
in partnership with these research institutions:
- Joint Institute for Food Safety and
Applied Nutrition (JIFSAN).
In FY 2000,
the JIFSAN partnership between FDA and the University of Maryland continued
its involvement in areas of risk assessment and education. For example, in that year,
a database on temperatures of stored and cooked foods, based on a survey by
Audits International, became the first significant risk data posted to JIFSAN's Food
Safety Risk Analysis Clearinghouse, a resource for those interested in food safety
risk assessment, management and communication. "This type of project fit
in perfectly with our role of providing a science base for sound health policy
by filling in gaps in needed knowledge," explains JIFSAN Director David
Lineback, Ph.D. JIFSAN was also a key player in international "good agricultural
practices" training programs undertaken in FY 2000.
- National Center for Food Safety
and Technology (NCFST).
This joint effort of the Illinois Institute of Technology, FDA
and the food industry continued its groundbreaking work in FY2000
developing alternative technologies to enhance the safety of food products, such as sprouts or juice, that have the potential for
causing foodborne illness. For example, in FY
2000 NCFST initiated or continued work on projects related to the following issues:
the effectiveness of microwave energy for pasteurization of in-shell eggs; tests
of spent irrigation water to prevent the release of sprouts contaminated with
pathogens; the efficacy of thermal and nonthermal technologies for elimination of pathogens
in fresh fruit juices and other foods; the potential allergenicity of new food
proteins in genetically modified foods; molecular subtyping of
Listeria monocytogenes and Vibrio
parahaemolyticus; and survival of food pathogens during the 60-day
aging period of hard cheeses made from unpasteurized milk.
"The center's research projects bring together participants from industry, FDA,
and academia," explains NCFST Director
Charles Sizer, Ph.D., adding that "the
collaboration works because, when it comes to food
safety, we're all on the same page."
- Other Cooperative Efforts.
In FY 2000, FDA continued to seek involvement
with the scientific community, through such mechanisms as CFSAN's
"post-doc" program, extramural grants and
cooperative agreements with outside experts. "These kinds of collaborations
fill the scientific gaps when FDA doesn't have expert personnel or specialized
equipment needed in a targeted research
area," explains Arthur Miller, Ph.D., CFSAN's Lead Scientist for Microbiology.
"The programs allow us to tap talent from
various scientific institutions and, with their input,
to develop guidance and policies much faster than we otherwise could."
Bolstered by additional food safety funding, and often in collaboration with the
partners previously described, FDA made important strides in FY 2000 toward better scientific
data, methods, and models. The following were among the significant accomplishments in
that fiscal year:
- developed an improved polymerase
chain reaction (PCR) method for detecting
Cyclospora. The method, which has been used by FDA and CDC, provided the
first isolation of this pathogen from a food product associated with human illness.
- demonstrated that surface heating of
apples is not an effective method of improving the safety of apple juice. An
accompanying thermal penetration model was
developed that showed there is minimal penetration
of heat below the surface. Therefore, while heating eliminated
microorganisms, including E. coli 0157:H7, from the
apples' surface, it was not effective in
destroying microorganisms that had migrated into
the apples.
- demonstrated that temperature plays
a critical role in inactivation of common types of
Clostridium botulinum spores during high pressure processing (HPP). No
direct relationship was observed between the thermal resistance of
C. botulinum spores at atmospheric pressures and the
thermal resistance at elevated pressures.
- demonstrated that pulsed electric
field (PEF) energy and heat work together in the destruction of
Listeria monocytogenes.
- developed an improved procedure for
the quantification of the natural toxin patulin in
fruit juices and demonstrated that patulin levels in apples are a reasonable
indicator for dropped or moldy apples.
- successfully applied a reverse
transcription polymerase chain reaction (RT-PCR) method to the detection of Hepatitis A
virus in shellfish, water and cilantro.
- in conjunction with the U.S. Department
of Agriculture (USDA), funded a pilot project with eight federal, state and
local laboratories to develop standards for E.
coli 0157:H7 sampling and testing (to be completed in FY 2001).
- developed a multiplex PCR method to characterize new and unusual strains
of pathogenic E. coli. The method simultaneously characterizes five
genetic features and allows FDA to recognize a much broader range of
enterohemorrhagic E. coli than is possible with other,
0157:H7-specific methods.
- developed a draft risk assessment
that examined the risk of foodborne listeriosis from eating certain ready-to-eat foods,
to the point where release of the document could be planned for January 2001.
"The information from the risk assessment
will guide future policy on Listeria
monocytogenes, helping to direct resources where the greatest impact on public
health can be achieved," says CFSAN's
Microbial Risk Assessment Coordinator, Sherri Dennis, Ph.D.
- developed a draft risk assessment on
the public health risks associated with raw oysters containing
pathogenic Vibrio parahaemolyticus. Launched in
response to widespread outbreaks in 1997 and 1998, the project addressed questions such
as: how often Vibrio parahaemolyticus
occurs in water and in shellfish, the relationship
of the level of the bacteria ingested to the severity of illness, the differences
in response to the bacteria for consumers with various health conditions, and the
influence of post-harvest handling on the numbers
of Vibrio parahaemolyticus pathogens in oysters. Like the
Listeria monocytogenes risk assessment, the project will provide
a scientific framework for developing health-improving food safety guidance and policy.
- improved the analytical method for detection of
Vibrio parahaemolyticus and transferred this technology to FDA
and state regulatory laboratories.
- developed improved tests aimed at detecting and avoiding the development
of antibiotic-resistant bacteria in the human food chain. With FDA's Center
for Veterinary Medicine (CVM) and National Center for Toxicological Research
(NCTR) taking lead roles, the agency's recent antibiotic resistance-related research
has included a showing that the "agar
dilution test" may be uniquely reliable for quantifying antimicrobial susceptibility
in Campylobacter; the undertaking of
studies to determine the epidemiology of antimicrobial resistance in
Salmonella and shigatoxin-producing E.
coli (such as E coli 0157:H7) organisms as they
move longitudinally from feed into animals; and an application of risk
assessment methodology to antibiotic resistance to
better predict the extent of public health risk.
- requested that the American Gastroenterologist Association survey
its members regarding the incidence of gastroenterological parasitic infections
in the United States resulting from consumption of raw fish. (Survey will
be completed in FY 2001.)
CFSAN updated its food safety "Three-Year Research Plan," which keeps FDA's food
safety research on track with regulatory objectives.
"Our research plan is not carved in
stone," explains John Newland, Ph.D., CFSAN's Microbial Research Coordinator. "At a
given time, the three-year plan provides a snapshot
of where the agency projects it will be in terms
of research accomplishments."
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