Articles in this issue:
Food processors know that meat must be heated to at least 160
degrees Fahrenheit at its innermost point to ensure that harmful
bacteria in the meat are killed. But to make certain they have
reached that internal temperature, processors may have to overcompensate
by turning on so much heat that it cooks the rest of the meat
more than necessary. It would be good to determine just when the
center of the thickest part of a piece of meat reaches the required
temperature. Food Safety Consortium researchers at the University
of Arkansas have found a way to do it --- they built their own
custom-made oven.
The oven was designed by a team led by Joel Walker, a principal
investigator in the Consortium and a professor of biological and
agricultural engineering. This group worked to accommodate needs
prescribed by another principal investigator, Michael Johnson,
a professor of food science
The oven was recently installed and will be used to analyze thermal
penetration of meat products. Equipment testing over the coming
months will be conducted by Jim Goff, a doctoral degree candidate
and a senior graduate assistant in food science, and Jing Yan
Luo, a master's degree candidate and a graduate assistant in biological
and agricultural engineering.
The oven was assembled on the Fayetteville campus with parts acquired
for about $5,000. "It would have cost $20,000 to $30,000
to buy a ready-made large commercial oven," Walker said.
And if one had been purchased, researchers still would have had
to manipulate its instrumentation to accomplish what they want,
Walker said. The researchers can modify the custom-made oven and
adjust its internal components for individual experiments.
The oven can be modified to change the temperature, the heat flow
and the intensity level in evaluating how these factors affect
the food quality while destroying potentially harmful microbes.
Walker explained.
Eliminating bacteria in uniformly shaped meats such as hamburger
patties does not pose the problem that processors potentially
face with irregularly shaped meats such as chicken pieces. The
research oven is designed to measure how quickly and at what point
all the bacteria are killed in whole muscle foods such as chickens
and their components made up of thick and thin portions.
Johnson explained that the researchers will be looking into the
"heat-cook factor," which he described as the opposite
of the wind-chill factor. They will review the effects of heat
intensity on chicken as it progresses through the cooking process.
With irregularly shaped meat products such as chickens, "what
we want to do is get the minimum time to get a good quality product
that's properly cooked, but not overcook it," Johnson said.
Overcooking the product will still ensure that the bacteria are
killed, but then its marketability is threatened.
"You are drying out your product," Johnson said of the
results of overcooking. "You lose moisture, juiciness, possibly
tenderness. You want to find the amount of time that will kill
all bacteria while giving an optimal quality product."
Or, as Goff described, "get it so the thickest part of it
is done while the thinnest part of it is still maximum quality."
Bacteria can enter chicken tissue during the marinating process.
Many whole muscle products are marinated to enhance the flavor,
juiciness and texture. Marinating lessens the loss of water during
cooking and maximizes the yield. Chicken pieces are placed in
a vacuum tumbler, a sealed chamber in which the air is removed
from the product and liquid marinate is forced into the meat.
The bacteria that enter chicken via the marinating process can
grow exponentially. They can quickly multiply over 1 to 2 minutes,
accumulating into the millions. The good news is that when heat
begins killing them, they die in large numbers at an equally quick
rate. But, Johnson explained, "there's a potential for the
last part of the (surviving bacterial) population to be more resistant
and not die off at the same fast rate as the initial part of the
population." The goal is to make sure those last survivors
are finally killed.
The last stand of the surviving bacteria is aided partly by the
irregular shape and varying thickness of whole muscle products.
That wouldn't be a problem in killing bacteria in a liquid product
such as milk because the heat can be distributed more evenly during
the pasteurization process. The experimental oven is designed
to help scientists develop a process for decontaminating whole
muscle products on a time and temperature basis similar to pasteurization.
The oven is designed to determine what it takes to destroy all
the bacteria and how long it takes to do it. For experimental
purposes, an incision is made into a chicken breast and beads
containing Listeria bacteria are laid into the thickest
and coldest portion. A non-pathogenic derivative of Listeria
is used instead of the pathogenic Listeria monocytogenes bacteria
that often invade meat products. But the non-pathogenic derivative
has the same heat-resistant characteristics as Listeria monocytogenes.
To measure the impact of the heat, the researchers place temperature
sensors into the meat as it proceeds down the oven's conveyor
belt, creating a running temperature profile. The thermocouples
are hooked into a computer which records the temperatures in specific
parts of the chicken during different times in the cooking process.
After that part of the experiment is complete, the temperature
profile history is correlated with the bacteria casualty rate.
The question at this point is are there any survivors.
Johnson noted the researchers know how many bacteria were inserted
into the chicken. "We can come back to where these beads
were. They'll still be intact. We'll then ask if there are any
viable bacteria left in those beads in the cooked chicken. We'll
open the chicken back up and pull it out. ... If things are behaving
properly at a certain amount of temperature, we ought to get down
to where we have thousands of grams of chicken, and there might
be a tiny amount of viability left in a tiny amount of bacteria
that you can't even count."
Under such circumstances, it is likely that there won't be any
surviving bacteria in the thin part but there may still be a few
in the thick part. Zero tolerance in a 25-gram sample per cooked
product is still the operative standard under USDA rules because
some people with low tolerance levels for disease are susceptible
to food poisoning from small amounts of bacteria.
To make sure all the bacteria have been killed --- right down
to the hardiest resisters deep in the interior of the meat ---
researchers want to find out exactly how long the heat needs to
be on at what temperature and how much humidity to allow during
the cooking. Moisture accelerates heat transfer and the experimental
oven can control the humidity level in addition to the temperature
during cooking.
"We want to optimize the cooking in the oven and the temperature
and time so we get the maximum heat transfer in the cold part
of the meat and optimize that time that we get it fully cooked
to the prescribed temperature and at the same time destroy the
bacteria that could be there," Johnson said. As a safety
margin, scientists aim at more bacteria than they believe are
probably there, thus increasing the chances of killing any resistant
bacteria.
"That's what we want," Johnson said. "Lots of kill."
The Consortium looks to its Steering Committee for guidance of
its activities. The committee is comprised of representatives
of the Consortium's three member universities, the U.S. Department
of Agriculture and the pork, meat and poultry industries. These
committee members meet at least once a year and review research
progress. As necessary, they recommend changes that may be required
to accomplish the Consortium's congressional mandate.
The Consortium and its researchers benefit from the expertise
and varied backgrounds the committee members bring to their task.
They review the proposed projects for the next fiscal year to
ensure that the Consortium is progressing toward meeting its purpose.
These individuals take their roles seriously as contributing members
of a team that has made its mark in food safety research in its
few years of existence.
This year the Consortium Steering Committee has 12 members; five
of them are new additions. Their first assignment was to prepare
for the annual meeting in Kansas City and to become familiar with
the projects they would be reviewing. The new members are:
* Frank Flora, food scientist and program manager for the USDA
Cooperative State Research, Education and Extension Service in
Washington.
* Brenda Halbrook, research coordinator for science and technology
of the USDA Food Safety and Inspection Service in Washington.
* Jim Riemann, director of fresh meats for the Excel Country Fresh
Meats Product Development Center in Wichita, Kan.
* Colin Scanes, associate director of the Iowa Agriculture and
Home Economics Experiment Station and associate dean of the College
of Agriculture at Iowa State University.
* Lee Ann Thomas, laboratory coordinator for the Food Safety Inspection
Service's Animal Production Food Safety Program at the National
Veterinary Services Laboratory in Ames, Iowa.
We thank these qualified individuals for agreeing to devote part
of their time and energy to the advancement of food safety and
the Consortium's efforts. We also thank the former committee members
who recently stepped down from their positions. They are Dell
Allen of the National Cattlemen's Association in Wichita, Clark
Burbee of the Cooperative State Research, Education and Extension
Service in Washington; Donald Derr of the Food Safety and Inspection
Service in Washington, Tom Fretz of the Iowa Experiment Station
and Stan Harris of the National Veterinary Services Laboratory.
The Steering Committee retains the services of several individuals
who are joining me for another year of work on the panel. They
are Ellis Brunton, group vice president for research and quality
assurance at Tyson Foods in Springdale, Ark.; James Denton, director
of the Center of Excellence for Poultry Science at the University
of Arkansas and head of the Department of Poultry Science; Richard
Forsythe, distinguished professor emeritus of poultry science
at the University of Arkansas and the Consortium's former coordinator;
George Ham, associate director of the Kansas State University
Agricultural Experiment Station; Jack Riley, head of the Kansas
State University Department of Animal Sciences and Industry, and
Mike Telford, president of the Iowa Pork Producers Association.
The Consortium's Technical Executive Committee has undergone some
changes. I am taking Dick Forsythe's place as chair and the Arkansas
representative. Frank Flora is succeeding Clark Burbee as the
CSREES representative. George Beran, professor of veterinary microbiology
and preventive medicine at Iowa State, and Curtis Kastner, professor
of animal sciences and industry at Kansas State, will continue
on the committee.
Committee work is a calling and at times a burden, but its rewards
are evident in the Food Safety Consortium. Thanks to everyone
for their past, present and future service.
Numerous tests have been performed over the years to determine
the effects of irradiation on microorganisms. Food Safety Consortium
researchers at Kansas State University recently examined the effects
of low-dose irradiation on the quality of boneless pork chops,
beef steaks, precooked ground beef patties and raw ground beef
patties. They found that irradiation did not adversely affect
traits such as color, product life, flavor and aroma characteristics.
"I think the safety of irradiation is established,"
said Don Kropf, the principal investigator at KSU who headed the
project. This set of irradiation studies was aimed at determining
whether irradiation would cause quality changes that might leave
consumers wary.
Irradiation preserves food by exposing products to high-energy
ionizing radiation. The radiation energy changes the molecules
so that, at sufficient doses, microorganisms are killed so they
cannot cause spoilage or illness. A dose of food irradiation is
the amount of radiation absorbed by the food.
The amount of radiation absorbed in dosages is measured in kilograys
(kGy). The World Health Organization considers any food irradiated
up to an average dose of 10 kGy to be wholesome and safe for consumption.
In the KSU project, the beef steaks were treated to irradiation
dosages of 0, 2 or 3.5 kGy. Irradiated frozen steaks were thawed
overnight; chilled steaks were stored 14 days, after which half
of them were covered with PVC film overnight.
A panel of five professional flavor profilers assessed the steaks
for attributes of texture and flavor. They found that irradiation
did not influence the frozen steaks' toughness, juiciness, meat
identity, browned-roasted traits, bloodiness, fat-like aspects,
metallicness, liver-likeness, sweetness, sourness or bitterness,
their internal or external cooked color values or aroma. In all
the categories, the measured levels of those traits on the irradiated
steaks were not significantly different from the levels recorded
for the unirradiated steaks. The steaks' redness increased in
the steaks irradiated in the 2-3.5 kGy range.
Irradiation also did not influence the chilled steaks' juiciness,
fat-like aspects or their metallic, sweet or bitter flavor notes.
It also did not affect their internal or external cooked color
values.
Similar studies reviewed the results of irradiation when applied
to frozen raw and precooked ground beef patties with raw fat levels
of 10 percent and 22 percent. Patties were treated to doses of
0, 2 or 3.5 kGy. The results showed that the dosage level, the
package type and fat percentage did not affect most of the patties'
flavor and aroma attributes. Irradiation increased the external
redness in the vacuum-packaged precooked ground beef.
The tests on the boneless pork chops measured consumer acceptance
of irradiated chilled pork chops as well as flavor and aroma characteristics
of chilled and frozen irradiated chops as assessed by the professional
panel. There were few major differences between the control and
irradiated chops despite varying irradiation sources, packaging
types or storage temperatures. A panel of consumers --- 80 percent
of them between ages 26 and 55, more than half having some college
education --- observed no differences between the irradiated and
control samples when evaluating the chops' overall acceptability,
meatiness, freshness, tenderness and juiciness.
The pork chops study was the only one accompanied by a study of
consumer acceptance. "Consumer studies are quite expensive,"
Kropf said, noting that funds were available for only one study.
Results of the research have already been presented at the 41st
International Congress of Meat Science and Technology in San Antonio
and at the American Meat Institute's mini-conference on meat irradiation
at which Kropf was one of the four speakers. A press conference
involving trade magazine representatives was also held in San
Antonio. Kropf also expects to present the findings next year
at the Institute of Food Technologists convention in New Orleans.
Noting the safety of irradiation is no longer in question, Kropf
said there are still related aspects of the process that should
be studied. "We think that the greatest need for research
is to fine tune the system, particularly in regard to packaging,"
Kropf said.
Research on the steaks and ground beef was sponsored by the American
Meat Institute Foundation and the Cattlemen's Beef Promotion and
Research Board. The pork chops' study was sponsored by the National
Live Stock and Meat Board and the National Pork Producers Council.
Richard H. Forsythe of Arkansas, a member of the Consortium
Steering Committee, was named a Fellow of the Poultry Science
Association in August during the organization's annual meeting
in Edmonton, Alberta. Forsythe recently stepped down as coordinator
of the Consortium and retired from the University of Arkansas
faculty, where he was a distinguished professor of poultry science.
The PSA grants the title of Fellow for professional distinction
and contributions to the field of poultry science without concern
for longevity. No more than five members may be elected as Fellows
at any one annual meeting.
Forsythe has compiled a 47-year career in the academic world and
industry, specializing in poultry products, food safety and nutrition.
He produced 46 refereed journals from his research.
Forsythe earned his bachelor's and doctoral degrees at Iowa State
University and served there as an instructor, an assistant professor
and department head. He was an adjunct professor at Pennsylvania
State University. After his employment in industry, Forsythe joined
the University of Arkansas faculty.
His industrial experience included administrative duties associated
with research related to product development and safety. Forsythe
served as associate director for food research at Armour &
Co.; director of central laboratories, vice president for research
and vice president for technical affairs at Henningsen Foods,
Inc.; and vice president for basic research at the Campbell Institute
for Food Research of the Campbell Soup Co.
Forsythe has served on committees of several professional organizations,
including the Poultry Science Association, the Institute of Food
Technologists, the Institute of American Poultry Industries, the
Poultry and Egg National Board, the World Poultry Science Association,
the American Poultry Historical Society, the National Research
Council, the Nutrition Foundation, the Southeastern Poultry and
Egg Association and the Arkansas Poultry Federation.
His awards and honors include installation in the American Poultry
Historical Society Hall of Fame, selection as Arkansas Poultry
Federation Man of the Year and Poultry Industry Man of the Year,
and receipt of the Contributions to Poultry Industry Above Gain
for Self or Employer Award, the Missouri State Award of the National
4-H Alumni Recognition Program, the Institute of American Poultry
Industry Research Award and the Monsanto Award. Forsythe has been
named a Fellow of the Institute of Food Technologists.
Curtis Kastner and Randall K. Phebus and other
researchers from Kansas State presented a paper, "Standardized
Microbial Sampling and Testing Procedures for the beef Industry,"
at the 41st Annual International Congress of Meat Science and
Technology in August in San Antonio.
Daniel Y.C. Fung and Curtis Kastner of Kansas State
presented a paper at the 41st Annual International Congress of
Meat Science and Technology on "Reduction of Listeria
Monocytogenes, Escherichia Coli 0157:H7 and Salmonella
Typhimurium During Storage on Beef Sanitized With Fumaric,
Acetic and Lactic Acids."
Melvin Hunt and Don Kropf of Kansas State presented
a paper on "Expressible Juice and Internal Cooked Color of
Ground Beef Patties From Vitamin E-Supplemented Steers" at
the 41st annual International Congress of Meat Science and Technology.
James H. Denton of Arkansas presented paper on "Role
of the Land Grant University in HAACP Education" at the Food
Safety Workshop of the Poultry Science Association at the University
of Alberta in Edmonton.
Paula J. Fedorka-Cray of the National Animal Disease Center
at Iowa State has submitted four articles for publication in journals
during 1995. "Alternate Routes of Invasion May Affect the
Pathogenosis of Salmonella typhimurium in Swine" was
published in Volume 63 of Infection Immunity. "Influence
of Inoculation Route on the Carrier State of S. Choleraesuis
in Swine" is in press at Veterinary Microbiology.
Articles that have been accepted for publication are "Transmission
of Salmonella choleraesuis to Naive Swine" in Applied
Environmental Microbiology and "Effect of Dose on Persistence
of S. Choleraesuis Infection in Swine" in the American
Journal of Veterinary Research.
Daniel Y.C. Fung of Kansas State made several presentations
in April in Brazil as part of the United States Information Agency's
Scientific Speaker Program. At a symposium in Gramado, Fung lectured
on biodeterioration and made a presentation and chaired a discussion
on rapid methods. At the University of Sao Paulo, he lectured
at the Institute of Food Technology and at the Department of Food
and Nutrition on advances in rapid methods in microbiology. In
Rio de Janeiro, he lectured at Federal Fluminense University on
food technology and at the Rio State Foundation of Environmental
Engineering on "Recovering of Biodegraded Waters, Water Purification
and Treatment." In Recife, Fung lectured at the Federal University
of Pernambuco and discussed "Water and Solid Residues in
the Process of Environmental Degradation" and "Rapid
Methods" at a lecture sponsored by the Brazilian Association
of Sanitary Engineering. He also conducted a press interview on
environmental clean-up suing rapid methods systems and met with
reporters from O Globo and Ecologia e Desenvolvimento
magazine. Articles about his visit were also published in O
Estado de Sao Paulo and the Journal do Commercio.
In July and August, Fung was a visiting scholar to Budapest, Hungary,
at the university of Horticulture and Food Science on an Organization
for Economic Cooperation and Development Fellowship.
Fung was also recently designated a Fellow of the Institute of
Food Technologists in recognition of his contributions to food
science and technology.
In addition to his interviews in Brazil, Fung has been featured
in several newspaper articles in recent months. He was interviewed
in the Wichita Eagle in an article on food preparation
practices; in Ouest France and in Food Chemistry News
of Tokyo.
Fung was the author of "What's Needed in Rapid Detection
of Foodborne Pathogens," which appeared in the June 1995
edition of Food Technology.
At the Kansas State campus in July, Fung was the director of the
15th anniversary workshop on Rapid Methods and Automation in Microbiology.
About 150 people from 23 states and 15 countries participated
in the eight-day workshop.
Richard H. Forsythe of Arkansas participated in the Institute
of Food Technologists media training seminar in August in Chicago.
The seminar, for food science communicators, covered working with
news media.
Amy Waldroup of Arkansas received the Continental Grain
Poultry Products Research Award in August at the Poultry Science
Association meeting in Edmonton, Alberta. She received grants
of $10,000 from Cargill, Inc., and $15,000 from Rio Linda Chemical
Corp. The award is presented annually to the person who has
accomplished outstanding research in the field of poultry products.
Waldroup was cited for her work on food safety issues in poultry
products, particularly with factors that influence salmonella
contamination. She has focused on methodology of detection, intervention
and eon points for salmonellae control and has suggested various
feeding and management practices that aid in the reduction of
salmonellae numbers on processed carcasses.
Waldroup also presented a paper in July entitled "Chemical
Decontamination of Poultry Carcasses" at the annual meeting
of the International Association of Milk, Food and Environmental
Sanitarians in Pittsburgh.
Two articles that Waldroup co-authored were published in the May
1995 edition of The Journal of Food Protection --- "Performance
Characteristics and Microbiological Aspects of Broilers Fed Diets
Supplemented with Organic Acids" and "Antibacterial
Activity of a Sodium Acid Pyrophosphate Product in Chiller Water
Against Selected Bacteria on Broiler Carcasses."
Food Chemical News used material presented by Mary Scantling,Waldroup's
research assistant, on the market quality of TSP-treated turkeys.
The presentation was made at the Poultry Science Association meeting
in Edmonton.
Chuck Banks, district director for Rep. Pat Roberts
of Kansas, chairman of the House Agriculture Committee, met
in September with Consortium researchers at Kansas State to review
research projects.
Secretary of Agriculture Dan Glickman delivered the Landon
Lecture in September at Kansas State. Consortium researcher Jim
Marsden of Kansas State and representatives of the Kansas
Livestock Association met with Glickman to discuss research and
inspection issues.
The Food Safety Consortium Newsletter is starting a
new feature. Each edition will present a roundup of items about
developments in food safety around the nation. Sources include
announcements from public agencies, trade publications, general
interest newspapers and magazines and the Internet. And those
are just the items we see in this office. If you come across an
interesting article that ought to be brought to Newsletter
readers' attention, send it to us at 110 Agriculture Building,
University of Arkansas, Fayetteville, Ark. 72701, via fax to 501-575-7531
or through e-mail to dedmark@comp.uark.edu.
* * *
Sens. David Pryor of Arkansas and Richard Lugar of Indiana in
August introduced the Food Quality Protection Act of 1995. The
bill would reform the Delaney clause of the Federal Food, Drug
and Cosmetic Act, a 1958 measure that set standards for pesticide
levels in raw and processed foods. The Delaney clause allowed
no tolerance of pesticide levels in foods, but "since that
time, improvements in technology have shown us that traces of
pesticides covered in the Delaney clause pose no public health
risk," Pryor said. Pryor added that U.S. agriculture has
been at a disadvantage in world markets because of the Delaney
clause. The Pryor-Lugar bill would also create a single risk standard
for pesticide levels in both raw and processed foods and also
calls for the U.S. Department of Agriculture, the Environmental
Protection Agency and the Department of Health and Human Services
to coordinate their pesticide data collection procedures.
* * *
USDA researchers have found that a bacterial blend called CF3
significantly reduces salmonella in broiler chickens. One hundred
broiler chicks were treated with CF3 and another 100 were not.
Two days later, all 200 chicks were each given 10,000 Salmonella
typhimurium bacteria. Four weeks later, the broilers' intestines
were checked and the CF3-treated birds had fewer than 10 Salmonella
typhimurium bacteria per gram of cecal (intestinal pouch)
content. The untreated birds each had about 3,000 Salmonella
typhimurium bacteria.
"The results indicate treatment with this bacterial blend,
which we call CF3, may be a useful part of an integrated program
to reduce salmonella in broilers during growout and reduce salmonella
in the chicken house," said Michael E. Hume, a research biologist
with the USDA Agricultural Research Service.
The tests were conducted last spring at the ARS Food Animal Protection
Research Laboratory in College Station, Texas. The researchers
produced CF3 by selecting 29 different types of bacteria from
hundreds present in the ceca of older chickens and using those
microorganisms to produce a defined culture. Hume reported the
results at the annual meeting of the Poultry Science Association
in Edmonton, Alberta.
* * *
Parade, the magazine inserted with hundreds of Sunday newspapers
across the nation, published a full-page article in August by
Peter Hellman entitled "Don't Let Your Food Make You Sick."
The article explained that foodborne illnesses are often caused
by the wide distribution of a product contaminated at a single
plant. But it assured consumers that the key to keeping themselves
safe from such problems is to practice routine precautions: keeping
hands clean, keeping refrigerators at no higher than 40 degrees
F, cooking foods at 180 degrees F, avoiding cross contamination
in the kitchen (such as keeping utensils used to cut a raw chicken
away from other foods until they have been washed), and cooking
ground beef until no pink is left inside and juices run clear.