Bacteriophages --- the friendly viruses
that can wreak havoc on harmful bacteria --- are being harnessed
to beat back Salmonella in livestock. A phage invented
and recently patented by food safety researchers at Iowa State
University is the first phage to control the spread of Salmonella
in swine and to prevent the bacterium from developing into a
vehicle of foodborne illness.
"The pen isn't the only place pigs get Salmonella,"
said D.L. (Hank) Harris, an animal science researcher at ISU.
"They've got Salmonella when they come in from the
farm. It turns out that vaccine and probiotics have not been
very successful in reducing Salmonella in lairage immediately
before slaughter. So we're using pigs in an acute infection model
to evaluate bacteriophage."
Harris' work to find effective ways to use bacteriophage in pigs
has been successful enough to warrant further study in a collaborative
Food Safety Consortium project later this year. Harris will team
with Billy Hargis, an FSC researcher who directs the University
of Arkansas Poultry Health Research Laboratory, to explore ways
to maximize production of bacteriophage and to determine its
effectiveness against various types of Salmonella.
Hargis has been pursuing FSC-supported research on bacteriophages'
effectiveness against Salmonella in poultry. The work
matches up well with Harris' pursuit of livestock-oriented work
that has been supported by the Biotechnology Research and Development
Corp., a nonprofit organization funded by federal and private
corporate money.
Market-weight pigs have been a particular problem because their
rate of testing positive for Salmonella generally increases
as they move from the farm to the holding pens to the slaughterhouse.
Salmonella infection comes from the environments to which
the pigs are exposed the transportation vehicles, the holding
pens, the other pigs and it comes quickly. "Healthy
pigs become Salmonella culture positive in tissue samples
within as few as three hours after infection resulting from exposure
to Salmonella-infected pigs," Harris said.
When released into infected animals, phages release their DNA
into the host cells of pathogenic bacteria, where they then produce
more phage that kill the host cells.
Harris' team at ISU invented the Felix 0-1 phage to reduce Salmonella
in livestock, which can be injected into the swine until about
three hours before slaughter and still be effective in controlling
Salmonella. The time window until the three-hour mark
is significant because pigs are especially at risk of infection
during those hours of being held in close quarters with other
pigs.
"Intervention with Felix 0-1 phage treatment following exposure
to Salmonella and prior to harvest is effective in reducing
the amount of Salmonella in an animal," Harris said.
"Alternatively, treatment of animals
prior to harvest will limit the risk of contamination of healthy
swine by infected swine in the event the animals were exposed
to Salmonella when housed with other animals or transported
to the slaughterhouse."
Using the Felix 0-1 phage between three and 24 hours before slaughter
has an advantage over other phages because it is lytic --- causing
the destruction of certain cells ---
for the most common serotypes of Salmonella that are present
in swine.
In addition to being administered to the animals orally, Felix
0-1 phage can also be applied to the finished product to reduce
Salmonella contamination. The phage can be applied to
the surface of the beef, poultry, lamb or pork by spraying or
soaking.
Bacteriophages have regained popularity in recent years as antibiotics
have run up against increasingly resistant bacteria. Bacteriophages,
which occur in nature, were discovered in the 1920s, Harris noted,
and were used to treat diphtheria and other diseases.
"But as soon as penicillin came out in the 1940s, nobody
wanted to work with phages anymore except the microbiologists,"
he said. The microbiologists used them to study the insertion
of genes in bacteria. Meanwhile, bacteriophage research and usage
continued in the Soviet Union because the Communist bloc nations
had difficulty obtaining antibiotics.
The new emphasis on bacteriophages has led to projects such as
development of the Felix 0-1 phage. "Our research now is
to see if we can make this a practical thing to do and if there
is a company that would be interested in marketing phage as a
product," Harris said.
Extracts From Grape Seed, Green Tea Keep Chicken
the Way Customers Want It
If the chicken is too tough or too red,
a dash of grapes and some tea can take care of it.
This is in the case of irradiated chicken. Irradiation eliminates
foodborne pathogens from the product but it can also cause some
undesirable sensory results, such as changes in color, off odors
and off flavors.
Food Safety Consortium researchers at the University of Arkansas
have found that the unwanted changes were minimized by infusing
grape seed extracts and green tea extracts into skinless, boneless
chicken breasts before irradiation.
Navam Hettiarachchy
of Arkansas has shown that using plant extracts can counteract
any problems in texture and appearance that irradiation causes
on chicken.
They also demonstrated that infusing a synthetic compound known
as TBHQ into the chicken was effective in minimizing oxidation,
the chemical process that causes the sensory changes in the food.
"TBHQ is a pure synthetic compound," explained Navam
Hettiarachchy, a UA Division of Agriculture food scientist. "Since
it's a pure compound and an antioxidant, it has the optimum activity
in preventing oxidation. Nobody so far has found anything as
good as TBHQ."
Additional good news from the findings is that the infusion of
plant extracts does not negatively affect the chicken's color
or water-holding capacity, Hettiarachchy said. Research has shown
that water-holding capacity is a critical factor for meat quality.
Although color changes don't affect the quality of the meat itself,
consumer acceptance of a meat product can be hurt if it has an
unfamiliar color. The meat's texture is also improved by the
infusion.
The grape seed and green tea extracts are already used in a variety
of food products. "Using these two extracts for improving
the quality of the meat during irradiation should not be a problem,"
Hettiarachchy said. "The technology is available for an
industry to transfer the technology."
The two extracts are cost effective because they are only 8 percent
water being introduced into the meat in very small quantities.
Also, sensory tests by trained panels have indicated that the
extracts at the concentrations used do not produce any off flavor
in the meat.
Tests have also shown that the extracts can extend the meat's
shelf life to 12 days. "The quality of the meat is maintained,"
Hettiarachchy said. "The quality includes the juiciness,
the water-holding capacity and the succulence."
From a Distance: Food Science Degrees at
KSU
The food safety field is requiring more
education of those in the industry who hope to hold key jobs
as well as those who already do. Utilizing information generated
by the Food Safety Consortium and others, Kansas State University
is offering food science degrees and certificates by distance
education.
It started in 1975 when tapes were the most advanced technology
for distance education. "The U.S. Department of Agriculture
came to K-State and said that they needed some continuing education
courses for their inspectors," said Kelly Getty, a program
coordinator for distance education and Food Safety Consortium
faculty researcher.
Kansas State is the only university offering distance education
as a way to complete a bachelor's degree in food science (for
those students who already have completed at least 60 hours of
undergraduate courses) or to complete the master's degree curriculum.
It also offers an undergraduate certificate or a graduate certificate
for students who complete 20 hours of course work in food science
but are not seeking a degree.
"Most of the students that we have are in industry,"
said Deanna Retzlaff, also a program coordinator for the curriculum.
"We have a few who are on campus. We also have quite a few
military people --- food inspectors and those with the veterinary
corps."
The distance education students are scattered far from Kansas
and not many of them have previously attended the university.
"Of the master's students, two are at Papa John's International
one in Florida and another in Kentucky," Getty said.
"They're already working in a corporate environment. We
have three students in Gaffney, S.C., working at a Stouffer's
plant. They're basically in places where there isn't a food science
program nearby. I have a masters student at a Cargill plant in
Iowa that also comes to K-State to recruit B.S. graduates and
undergraduates for internships."
There are more than 50 students completing bachelor's degrees
via distance education during a typical semester. About 12 master's
students are usually enrolled. A few students are seeking graduate
certificates and more than 30 students are accepted in the undergraduate
certificate program.
Distance education students who pursue the master's degree have
access to most of the courses that on-campus students can take.
Like the on-campus students, they must also choose between taking
28 hours of course work plus submitting a written report or taking
24 hours of course work and completing a full master's thesis.
A related grant has also facilitated Kansas State to add interactivity
to some courses, such as the Principles of HACCP and Applied
Microbiology for Meat and Poultry Processors courses. Retzlaff
explained that the interactive component equips the video that
students watch with segments that require students to answer
a question correctly before being permitted to continue.
Additionally, a series of videos on CD, each about 10 minutes
long, were funded though a USDA grant that paid for production
costs. Those 10 video modules have been incorporated in the Applied
Microbiology in Meat and Poultry Processors course.
Getty works with the KSU Division of Continuing Education to
market the distance education food science program nationwide.
Flyers and e-mail promotions are sent to prospective students
on the mailing lists for industries, professional associations
and the military among others along with advertisements in Food
Technology magazine.
Report From the Coordinator
By Gregory J. Weidemann
Scientific procedures are paying off for
public health. Food safety researchers have long advocated that
implementing science-based Hazard Analysis and Critical Control
Point methods in food production and processing would result
in a safer food supply. Now, the theory continues to be backed
up by the latest numbers.
The federal Centers for Disease Control and Prevention released
figures in late April showing that infections from five pathogenic
bacteria have been declining since 1996. The date is significant
because it was in 1997 that the U.S. Department of Agriculture
began mandating the use of HACCP in federally inspected meat,
poultry and egg products plants.
Elsa Murano, the USDA undersecretary for food safety and a former
Food Safety Consortium researcher from a few years back, delivered
the good news in a statement.
"The CDC noted significant declines from 1996 to 2003 in
illnesses caused by E. coli (42 percent), Salmonella
(17 percent), Campylobacter (28 percent) and Yersinia
(49 percent)," Murano said. "Illnesses caused by Salmonella
typhimurium (typically associated with meat and poultry)
decreased by 38 percent. Most significantly, between 2002 and
2003, illnesses caused by E. coli O157:H7, typically associated
with ground beef, dropped by 36 percent. The reduction in E.
coli O157:H7 illness brings the U.S. very close to achieving
the Healthy People 2010 goal of one case per 100,000 people."
Robert Tauxe, CDC's chief of Foodborne and Diarrheal Diseases
Branch, credits consumer awareness of food safety as one of the
factors in the decline. He pointed out that more consumers are
using thermometers when cooking meat (which, by the way, is another
result of a Food Safety Consortium research project) and more
are washing their hands before handling food.
The reporting of these numbers is possible because of FoodNet,
a surveillance system established in 1996 that quantifies, monitors
and tracks the incidence of laboratory-diagnosed cases of foodborne
illnesses caused by several bacteria. The data are collected
at sites in nine states across the nation.
There is still more work to be done. Tauxe said it was too early
to claim victory and that more time is needed before we can know
if this trend will be sustained. CDC targeted some specific areas
for future focus: Mandatory, on-farm efforts to reduce contamination
of eggs with Salmonella enteritidis, greater use of pasteurized
eggs and irradiated ground meat, and reduction of pathogens in
broiler chickens and turkeys, cattle and ground beef and seafood.
So there's not much doubt why Murano concluded her remarks by
saying the new data provide a challenge. "Through research,
education and the application of effective regulations, we intend
to make the safest food supply in the world even safer,"
Murano said.
As usual, that's where we come in. The research and education
are our critical tasks. The food safety community can accept
the congratulations for its work in getting us to this point
as we work to raise the bar higher.
KSU Grant to Address Agroterrorism, Food
Security
For the next five years, Kansas State
University's food safety program has been awarded a $2 million
grant from the university's Targeted Excellence effort that will
be used to address food safety and agroterrorism issues.
The project is known as Food Safety and Security --- Protecting
America's Health, Agricultural Infrastructure and Economy. It
will enhance KSU's existing food safety and security program
and provide additional expertise for the 34,000-square-foot BL3
Biosecurity Research Institute facility on campus as well as
the Bioprocessing and Industrial Value-Added Program.
"Students with comprehensive interdisciplinary training
in food safety and security are needed and this type of training
is non-existent," said Curtis Kastner, director of the KSU
Food Science Institute. "Students trained with the proposed
interdisciplinary perspective will be valuable, intellectually
diverse thought leaders."]
Kastner said KSU has a "rich history of successfully addressing
pre-harvest (animal and plant production) and post-harvest (food
microbiology and toxicology) issues that directly impact food
safety." Threats of attacks by terrorist on production agriculture
and the national food and water supply are a new concern and
have prompted initiatives to address the dangers to the public.
"Fortunately, past pre- and post-harvest food safety research,
teaching and extension efforts have put KSU in a strong position
to address this new era of agroterrorism and food security,"
Kastner said.
KSU has also developed social science programs that address food
safety and security issues. Kastner cited the integration of
communication, history, policy, social work and economics with
food science "that will make the KSU Food Safety and Security
effort comprehensive and unique."
Cases of E. coli O157:H7 infections
--- one of the most severe foodborne diseases showed a
dramatic decline last year, decreasing 36 percent compared to
the previous year, according to foodborne surveillance data released
April 29.
The data released by Centers for Disease Control and Prevention
in collaboration with the Food and Drug Administration and the
Department of Agriculture also showed that the incidence of three
common foodborne diseases --- Campylobacter, Salmonella and
Yersinia infections continued substantial declines
seen in the past eight years.
The overall incidence of E. coli O157:H7 infections has
declined 42 percent since 1996, while Campylobacter infections
have dropped 28 percent and Salmonella infections have
decreased by 17 percent.
Cases of other less common bacterial and parasitic foodborne
diseases have also decreased since surveillance began in 1996.
Yersinia infections have decreased 49 percent, and Cryptosporidium
infections have decreased 51 percent.
The data also found that the incidence of Listeria, which
had been decreasing the previous four years, did not decline
in 2003. The national Listeria Action Plan was launched
in 2003 to increase prevention efforts in the food chain, and
a method is being developed in order to rapidly identify contaminated
food items in outbreaks. The incidence of Salmonella enteritidis,
a common Salmonella serotype, has not changed significantly
since 1996, demonstrating that additional efforts are needed
to control this pathogen.
Children continue to suffer from foodborne illness in greater
numbers than other groups. CDC, FDA and USDA are currently conducting
a case-control study of sporadic cases of Salmonella and
Campylobacter to find the best opportunities for prevention
in young children.
Several factors have contributed to the overall decline in foodborne
illnesses. Enhanced surveillance and outbreak investigations
have identified new control measures and focused attention on
preventing foodborne diseases.
The USDA Food Safety and Inspection Service implemented the Pathogen
Reduction/Hazard Analysis Critical Control Point (HACCP) system
in all 6,000 federally inspected meat, poultry and egg products
plants over three years beginning in 1997. Since then, FSIS has
strengthened HACCP enforcement through innovative inspector training
and implemented rules to force plants to install new technologies
and other methods proving they are effectively controlling dangerous
pathogens like E. coli O157:H7, Listeria monocytogenes
and Salmonella.
Other interventions include the FDA's regulation requiring the
refrigeration and labeling of shell eggs to prevent Salmonella
enteritidis infections; HACCP regulation of fruit and vegetable
juices as well as seafood; extensive food safety education, publication
and outreach of good agricultural practices for fresh produce;
and increased regulation of imported food.
Foodborne pathogens annually are responsible for an estimated
76 million illnesses in the United States. In 1996, CDC, USDA
and FDA established the FoodNet surveillance system to quantify,
monitor and track the incidence of laboratory-diagnosed cases
of foodborne illnesses caused by Campylobacter, Cryptosporidium,
Cyclospora, E. coli O157, Listeria, Salmonella, Shigella, Yersinia
and Vibrio. Since its inception, the FoodNet system has
expanded to include nine sites and 41.5 million people, about
14 percent of the American population.
The full report, "Preliminary FoodNet Data on the Incidence
of Infections with Pathogens Commonly Transmitted Through Food
--- Selected Sites, United States, 2003" appears in the
Morbidity and Mortality Weekly Report (April 30, 2004)
and is available online at www.cdc.gov/mmwr. Partnerships
Viewed as Important to Food Safety
Partnerships --- both among domestic and
international institutions --- will be vital elements in promoting
food safety at the pre-harvest stage for animal products. Rich
Linton, director of the Purdue University Center for Food Safety
Engineering, outlined the need for partnerships during a session
in November at the Institute of Food Technologists Food Safety
and Quality Conference in Orlando.
"Developing partnerships is absolutely critical," Linton
said. The steps should include "integrating research institutions
and academic institutions with government, with industry and
with consumer groups to be able to develop and understand what
is the true role and responsibility of the producer and what
kind of risk production factor they can put in place."
Linton noted that the World Health Organization examined research
considerations and determined that epidemiology and risk assessment
were the most important ones. Both research areas are associated
with health issues in developing nations, he said.
"Developing countries raise specific concerns and issues
that are going to require assistance," he said. "Partnerships
are going to need to be reformed and it's absolutely critical
for these things to be done for them to be important players
in international trade."
International guidelines and standards will be increasingly important
as partnerships develop. "A key here is the ability to promote
science-based approaches, but also to understand the implementation
also has to deal with management," Linton said. "So
understanding the combination of science and management will
be key for both national and international issues."
The detection of hazards will also be important. "We're
trying to build systems that are better and more specific, but
really the key is making them affordable so the industry and
government organizations will want to use them. The challenge
in detecting hazards is not detecting the hazard itself but being
able to separate that hazard from the food system or from the
raw ingredient."
On the domestic front, Linton agreed with remarks emphasizing
education and outreach made earlier that day by Elsa Murano,
U.S. Department of Agriculture undersecretary for food safety.
In animal-based programs, state-level animal health agencies
and cooperative extension service units are important partners
in pre-harvest work.
"A combined partnership with these groups is absolutely
critical in connecting with the producer," Linton said.
Papers and Presentations
John (Sean) Fox
and Hikaru H. Peterson, Kansas State, published "Risks
and implications of bovine spongiform encephalopathy for the
United States: insights from other countries," in Food
Policy, 29 (2004): 45-60.
Joseph Sebranek, James Dickson, Aubrey Mendonca, Helen Jensen,
Dan Henroid and R.A. Martin, Iowa State, received
a $500,000 grant from the U.S. Department of Agriculture Cooperative
State, Research, Education and Extension Service for a project
on post-packaging irradiation combined with modified atmosphere
packaging for control of pathogens on meat products.
C,-M. Chen, Joseph Sebranek, James Dickson and Aubrey
Mendonca, Iowa State, published "Use of pediociin (ALTA
2341) for control of Listeria monocytogenes on frankfurters"
in the Journal of Muscle Foods, 15: 35-36.
Food Safety Digest
By Dave Edmark
The General Accounting Office, which serves
as the auditing and investigative arm of Congress, has long advocated
the merging of the federal government's oversight of food safety
into one single agency. The GAO released a report on the topic
more than a year ago. This spring, a GAO official testified before
a House subcommittee on the issue.
Lawrence J. Dyckman, the GAO's director of natural resources
and environment, suggested two points for Congress to consider:
enacting comprehensive, uniform and risk-based food safety legislation
and establishing a single, independent food safety agency. Another
possibility GAO offered was to instead modify the existing laws
and designate one current agency as the lead agency responsible
for all food safety inspection matters. GAO reported that more
than 30 food safety laws are currently administered by 12 federal
agencies.
"We can no longer afford inefficient, inconsistent and overlapping
programs and operations in the food safety system," Dyckman
said. "It is time to ask whether a system that developed
in piecemeal fashion in response to specific problems as they
arose over the course of several decades can efficiently and
effectively respond to today's challenges." Dyckman added
that a single integrated agency "can create synergy and
economies of scale and provide more focused and efficient efforts
to protect the nation's food supply."
Now there's something new to dread: Enterobacter sakazakii,
described as a rate but deadly pathogenic bacterium and vehicle
for foodborne illness. It is named for Riichi Sakazaki, a Japanese
bacteriologist, and was designated as a new species in 1980.
Recently it has cone to the attention of scientists that it might
be more prevalent than they previously realized. The Food and
Drug Administration has designated it as an emerging pathogen.
Peter Mrozinski, director of research and development for DuPont
Qualicon, wrote in the April-May edition of Food Quality
magazine that E.sakazakii can cause sepsis, meningitis
or necrotizing enterocolitis in newborn infants. Many of the
cases are fatal and survivors can suffer severe neurological
complications. Adults are also susceptible to infections from
the pathogen, particularly if they have serious underlying diseases
or malignancies. Some studies show that powdered infant milk
is a vehicle for infection. Other recent studies show that houseflies
are among the carriers of E.sakazakii.
Researchers have found the pathogen
in beef, sausage, meat, vegetables, cheese, powdered fruit flakes,
ultra-heat-treated milk, spoiled tofu, khamir and beer mugs rinsed
mechanically or in open vats.
* * *
The framework for a National Animal Identification System is
under way following Agriculture Secretary Ann Veneman's announcement
in April that $18.8 million will fund the program. The identification
system was instigated after discovery in December of a cow with
mad cow disease in Washington state. The system is designed to
identify the origins of animals with a foreign disease so that
the disease can be more quickly contained and eradicated.
The system will be implemented in three phases. First, USDA will
evaluate current federally funded animal identification systems
and determine which should be used for a national system, identify
staffing needs and develop legislative proposals. The second
phase would implement the chosen system at regional levels for
one or more selected animal species. In the third phase, the
system would be expanded to the national level.
Once a national system is selected, USDA will work with states,
Indian tribes and other government entities to assist them in
adapting their existing systems to the new system.
