The Food Safety Consortium Newsletter
Vol. 11, No. 3
Summer 2001
* Striking the Pathogens and Keeping Them Down
* FSC Annual Meeting Planned at ISU
* USDA Unveils New Food Safety Web Site; FSC Projects Included
* Advice to Processors: Don't Rely on the Models -- Test the Real Thing
* Report From the Coordinator
* Global Trade Should Prompt World Food Safety Effort
* New Opportunities Seen for Chemical Spray
* New Agri Secretary Seeks Cooperative Approach to Food Safety
* Papers and Presentations
* Food Safety Digest

Striking the Pathogens and Keeping Them Down
When poultry processors prepare their products as ready-to-eat, there is more at stake than just a tasty meal. The cooking process is also intended to kill pathogenic Listeria and Salmonella bacteria. But processors need to keep a close eye on the product. Sometimes a few of the bacteria are not dead, but just injured and recuperating.

In research experiments for the Food Safety Consortium, Rong Murphy of the University of Arkansas biological and agricultural engineering faculty found that cooking the poultry at low humidity levels enables more Salmonella to survive than when cooked at high humidity.

But the solution isn't as simple as just raising the humidity. "It depends on the type of product," Murphy said. "For some types, you have to cook it at low humidity. Some kinds of products, such as fried products, are processed at low humidity. Grilled products can be cooked at high humidity."

Injured pathogens can come back and survive at levels strong enough to endanger consumers. "Most of the time it takes three or four days to start having growth for heat-injured cells," Murphy said.

The cooking process can make a difference. Murphy explained that frying for a long time may not kill all the bacteria. But frying for a short time and then switching to convection cooking will likely kill all pathogens.

"That's why we conduct studies on different processes to see what type of pathogens are susceptible to what type of heat," she said.

Murphy's studies found that processed patties grew Salmonella and Listeria at lower rates when stored in a vacuum than when stored in air. Although vacuum packaging reduced growth levels, the procedure didn't kill the bacteria entirely.

"Even though the products are packaged, the bacteria can still survive under low oxygen conditions," Murphy said. "Vacuum packaging itself is not going to kill them."

The poultry industry is interested in the research and its implications for cooking procedures after processing. Murphy noted that the processors want to control quality as much as possible at the plant before shipping out the product.

Murphy's project tested the process to determine at what temperature pathogens become inactivated in chicken patties while heat slowly rises and humidity levels vary in an air convection oven.

Commercial processors, she explained, use both high and low levels of humidity. "That's their traditional practice, mainly from the quality and flavor viewpoint. We don't try to change their process. We try to evaluate it from a food safety viewpoint as to which point you should control."

The research has found that longer cooking times ensured that the necessary internal temperatures - 160 degrees Fahrenheit - were reached to ensure safety, but those longer times also result in increased processing costs and decreased product yield.

"We found that with some products cooking could cause 1 to 2 percent yield less for every 3 degrees Fahrenheit, depending on the process," Murphy said. "One company is interested in this point because it cooks nearly to 200 degrees and they lost a lot of yield."

Losing even small percentages worth of yield can be quite costly if a company operates a billion-dollar business, Murphy noted. Overcooking can cook more water out of the product, which cannot be added back in after processing.

The company that consulted with Murphy is using results of the study to determine how to improve yield as well as ensure food safety. "You can lose a lot of money without better process control."

FSC Annual Meeting Planned at ISU
The Food Safety Consortium will hold its annual meeting Sept. 16-18 at Iowa State University in Ames. In addition to the usual schedule of presentations by FSC researchers, this year's meeting will feature a symposium on risk and risk assessment.

The main segment of the annual meeting, intended primarily for FSC researchers and graduate students, will be held Sept. 16 and 17 at The Hotel at Gateway Center in Ames. A reception and poster session is planned for 6 to 7:30 p.m. Sept. 16. A full day of progress reports presented by FSC researchers and a continuation of the poster session will take place from 8 a.m. to 5 p.m. Sept. 17.

The FSC symposium will be held from 8 a.m. to noon Sept. 18 at the Scheman Building on the ISU campus. The symposium is open to non-FSC personnel for a $275 registration fee. Speakers for the symposium will include Anna Lammerding of Health Canada, Doug Powell of the University of Guelph, Canada and Alice Johnson of the National Food Processors Association.

To register for the symposium, contact Val Evans at ISU at or 515-294 3305.

USDA Unveils New Food Safety Web Site; FSC Projects Included

The U.S. Department of Agriculture has launched a new Web site ( aimed at providing a database of  food safety research projects to the research community and the general public. The Web site provides detailed information on food safety research projects, spending, and accomplishments by federal agencies, along with links to other important food safety research information.

             "This Web site is a tool that researchers and policy makers can use to examine research needs and priorities in food safety," said Agriculture Secretary Ann M. Veneman. "The goal is to  measure the progress of our food safety research and continue efforts to educate the public about these important issues."

             The searchable database provides information on nearly 500 food safety research projects - including those of the Food Safety Consortium - dating from 1998 to the present. The database also includes research done or funded by the USDA Agricultural Research Service; USDA Cooperative State Research, Education, and Extension Service and the U.S. Department of Health and Human Services' Food and Drug Administration.

            Also on the Web site are program and planning information, as well as various food safety reports, food safety news and information and more than 100 links to Web-based food safety research information provided by U.S. and foreign governments, and educational and     professional organizations. 

             The new Web site was created by the Food Safety Research Information Office at USDA's National Agricultural Library with information from related government food safety agencies. The National Agricultural Library, part of the Agricultural Research Service, is the world's largest and most accessible agricultural research library, and the principal resource in the United States for information about food, agriculture, and natural resources. 

Advice to Processors:
Don't Rely on the Models -- Test the Real Thing
Cooking pork sausage brings up the practical question of how much heat is necessary to ensure product safety and maintain sensory quality. Food processors consider factors such as the cost and the effectiveness of heat in killing pathogenic bacteria and its effects on taste.

Processors need to run their own tests to find out the answers to these questions because models won't necessarily tell the true story about the microbial destruction in meat. Iowa State University's Food Safety Consortium unit examined the effects of phosphates on pork processing and found that one uniform treatment does not fit all scenarios.

Scientists have developed models that are designed to predict the extent of heat destruction of certain foodborne pathogens as affected by environmental factors such as phosphates. Phosphates increase pork's water-holding capacity and improve safety by making Listeria monocytogenes less resistant to heat and more susceptible to destruction.

The behavior of foodborne microorganisms can be estimated by evaluating their growth or destruction in broth cultures or other model food systems. However, exceptions occur when an additional significant factor is present in the food but not in the model system.

For example, a relatively high fat content or phosphate level in ground pork could make a model unreliable for predicting the microbial safety or shelf life of pork sausage if the model lacks the same levels of fat or phosphate.

"Data on pathogen destruction from the use of model systems should just serve as a general guideline for processors to follow," said Aubrey Mendonca, a Food Safety Consortium researcher on ISU's food science faculty. "But we always tell them to validate, validate, validate."

Mendonca and a graduate research assistant, Makuba Lihono, looked at the effect of a phosphate, sodium acid pyrophosphate (SPP), on the heat destruction of Listeria monocytogenes in a model system involving pork slurry, a mixture of pork with peptone water. They also ran the same test using fresh ground pork. The research team inoculated the pork samples with Listeria monocytogenes and heated them at temperatures ranging from 55 to 62.5 degrees C.

"In the presence of SPP, the heat resistance of Listeria monocytogenes decreases greatly in the model system that used pork slurry," Mendonca said. "But we could not repeat these results in the fresh ground pork. We realized that fresh meat has some enzymes that degrade into orthophosphates, which have little or no antimicrobial activity. We demonstrated that the degradation of SPP by natural phosphates in fresh ground pork contributes to its ineffectiveness against Listeria monocytogenes."

Although the U.S. Department of Agriculture has developed predictive models, it agrees that processors should validate predictions from models by running tests with their own meat product. "The model system can never provide the exact conditions of a meat product, no matter how hard we try," said Mendonca. "There are some factors in meat that will not be present in a model system. Validation involves comparing results from tests in actual meat products with predictions from models."

Predictive models, when validated, can be useful in indicating when a food product might spoil or under what conditions foodborne pathogens such as Listeria monocytogenes might pose a health risk to consumers.

Processors often want to know what cooking temperature is best for killing pathogens without negatively affecting palatability, flavor and texture of the meat product. By using salt, phosphates, lactate and certain other ingredients, a processor can put enough stress on the organisms so that less heat is required to kill them. Lower heat means lower production costs.

Mendonca noted that there are other options for killing pathogens while allowing for lower cooking temperatures, such as irradiation although the procedure is still not in wide use. But following too many options can affect the product in ways that might make it less attractive to the consumer.

"Many times in sausage making you will add phosphates to increase product yield and protect flavor, but phosphates are not added primarily as an antimicrobial", Mendonca said. "So we've got to rely more on adequate heating of the product to ensure microbial safety."

Report From the Coordinator
By Gregory J. Weidemann
Consumers across the nation are becoming more aware of food safety issues and their own role in keeping contamination out of the food supply. The U.S. Department of Agriculture Food Safety and Inspection Service found that to be the case in a recent survey of focus groups in four cities.

That's something for scientists, administrators, businesses and government officials to keep in mind among what we call the "food safety community." The problems that the food safety community confronts regularly are not just matters for shop talk among ourselves. These topics involve the general public and they are listening to the discussion.

"People are more aware of pathogens, more aware of dangers," says Susan Conley, director of food safety education for FSIS. "They have confidence in themselves and in the food supply. They feel they know how to handle food. This is a new and different attitude. They are sure of themselves and sure of the food - even when they are sometimes wrong."

The Food Safety Consortium devotes a portion of its research to these direct consumer issues. A look at our projects shows the interest across our three member universities. At Arkansas, a team is exploring levels of consumers' acceptance of irradiated poultry. At Kansas State, research has demonstrated the importance of using oven thermometers to determine the internal temperature and doneness of cooked meat. Iowa State has launched a web site with food safety lessons for consumers and for food service personnel.

The FSIS survey is a good example of the need for research scientists in industry and academia to stay in touch with consumer concerns. The reason for the most basic of our research is to improve the safety of the food on our plates at home and when dining out. Whether we explore the procedures at the production and processing stages or at the distribution and consumption levels, our researchers have an abundance of issues to consider.

The subject of food safety's wide-ranging issues provides a good opportunity to put in a plug for this year's annual meeting of the Food Safety Consortium. Details about the event are published elsewhere in this issue. The meeting - Sept. 16-18 at Iowa State University in Ames - will cover the spectrum of our organization's research projects, with segments of the meeting separately emphasizing risk assessment, control and intervention strategies and sampling protocols methodology. A forum on the final morning of the meeting will feature guest speakers discussing risk communication.

The annual meeting is an example of communication among our scholars that plants ideas and generates additional research in the future. Our work should give the consumers of this nation confidence that no one in the food safety community is resting on past laurels.

Global Trade Should Prompt World Food Safety Effort, WHO Official Says

The world needs new food safety rules because increased global food trade means health problems can spread rapidly from country to country, a World Health Organization official said in July.

The Associated Press reported that Gro Harlem Brundtland, director-general of the WHO, told the Codex Alimentarius Commission, "The globalization of the world's food supply means the globalization of public health concerns. It is more and more difficult to solve food safety problems in one country without international collaboration."

The 165-nation commission, which meets every two years, is considering guidelines on bacteria control, pesticide levels in food, and biotech safety. The commission is a joint body of WHO and the U.N. Food and Agricultural Organization and met for a week in Geneva.

Brundtland said that high-profile outbreaks were only part of the problem, and that around one-third of the population of industrialized countries suffer from a foodborne disease every year. "Around 2 million children die every year from diarrhea in developing countries because of bad food and water," he said.

Brundtland also said that few developing countries have food safety systems, but more of them were trading with industrialized nations, so it is in their interest to adopt safety measures to protect both their own population and the populations of their trading partners.

New Opportunities Seen for Chemical Spray
Meat processors may soon have another tool at their disposal for reducing pathogenic bacteria. Tests at Kansas State University have shown that spraying a chemical on frankfurters and pork carcasses reduces pathogenic bacteria more effectively than water washing.

Acidified sodium chlorite reduced Listeria monocytogenes when applied to frankfurters in the processing plant, with reductions increasing as exposure time to the chemical was increased. Also, acidified sodium chlorite reduced the levels of E. coli and Salmonella when applied to pork carcasses during processing after slaughter.

Harshavardhan Thippareddi, a Food Safety Consortium researcher in the KSU animal sciences and industry department, explained that hot dogs usually have organisms loosely attached that are called plactonic cells. "Just regular washing with pressurized water and any similar treatments will remove some of the microbial cells from the surface. When we use acidified sodium chlorite we had better reductions compared to the washings with water or even dipping in water."

Thippareddi said the KSU research showed that the chemical treatment is effective on ready-to-eat meat products because the surface is cooked. The treatment is also effective on animal carcasses, he said, because the presence of organic material does not inactivate the chemical.

Thippareddi predicted that the process would be picked up by industry for frankfurters in perhaps a year or two. "I think we will have some optimized conditions where we could use this technology in industry," he said. "It is being used only in the poultry industry now. The beef processing industry is conducting validation tests of it."

Before the process is further developed for industrial use, Thippareddi's research team suggests studies to evaluate the chemical treatment's effect on sensory attributes such as color and flavor. No problems have been confirmed from visual observation, but there have been slight changes apparent.

For pork carcasses, organic acid rinses such as lactic acid or acetic acid are the predominant treatment in the processing plants. Acidified sodium chlorite is used in poultry processing, Thippareddi said. In all cases, he expects acidified sodium chlorite to become the most popular because of its superior performance.

"The advantage is that you can incorporate that with some minimal changes in the capital investment into the present organic acid rinse," he said.

Thippareddi said the next step would be to conduct in-plant validations of the procedures for pork carcasses that his team has tested on campus, similar to the in-plant validations already under way in beef carcass processing plants.

Future research may cover ways to extend these antimicrobial treatments to ground beef trim. "We are looking at a research project where we can evaluate the effects of acidified sodium chlorite, hot water and organic acid rinses for the beef trim that is supposed to go to ground beef manufacturers," Thippareddi said. "USDA regulations do not allow those treatments now because of the added water. When you do these washes you inevitably add some moisture to the product.

"In the future, USDA might come up with something that says if you are using these procedures as antimicrobial treatments then you would be able to use them."

New Agri Secretary Seeks Cooperative Approach to Food Safety
These are excerpts from a speech delivered by Agriculture Secretary Ann M. Veneman in April to the Food Safety Summit in Washington.

Through the Food Safety Inspection Service, USDA is responsible for ensuring the safety of the nation's meat, poultry and egg supplies. It's an important responsibility, and one that we take very seriously. ...

USDA's commitment to food safety remains strong.

In fact, the president's proposed budget provides funding for no fewer than 7,600 meat and poultry inspectors - without imposing user fees of any kind. And the total funding proposed for the Food Safety Inspection Service in FY 2002 is $716 million, an increase of $21 million over the 2001 level.

Our priorities at USDA regarding food safety fall into six categories.

First, we must begin with an understanding that the food chain has fundamentally changed over the past few decades. ...

When we look at the state of the food economy, we can clearly see that for any new policy to be successful and effective, it will have to be made with input and cooperation from every link in the food chain. This is especially true of food safety. Only a cooperative approach that integrates research, public health regulation, and education can lead to the formulation of effective policy that meets everyone's needs.

Second, we must work to ensure that all food safety policies are based on sound scientific principles.

Speculative or incomplete scientific research may be good for grabbing headlines, but it's a terrible basis for policy and regulation. That's why it is so important for those who conduct scientific research on behalf of the public to ensure that research is sound and reliable.

And it's just as important - if not more so - for those of us who oversee research and make policy based on its findings to accept only scientific studies that live up to the highest standards of methodological integrity. ...

Third, we must continue to educate the public about all aspects of food safety, from the testing we do at USDA, to safe handling practices for consumers.

People are naturally quite concerned about the safety of the food they eat. And while the general public cannot be expected to become food safety experts, it is certainly possible for them to understand the basic issues. A well educated public is better prepared to assess the validity of claims they may hear in the media, and to reject false or misleading information. And a well educated public will hold more realistic views of the safety of the food supply, and therefore be more confident in the food they buy and eat. ...

I want to mention one example of a successful public education effort before I move on. As you may have noticed, the "Fight BAC!" and "Thermy" characters are here representing consumer education activities. The "Fight Bac!" campaign promotes the four basic food safety rules - Clean, Separate, Cook, and Chill - while the "Thermy" campaign promotes thermometer use to indicate when products are cooked to a high enough temperature to kill harmful bacteria. And it's no accident that these campaigns were created in partnership with the private sector.
These are just two examples of what such cooperation can accomplish.

Fourth, we must ensure that USDA's food safety policymaking process continues to be transparent and that the public has the opportunity to provide input and be fully involved. ...

Fifth, we need to encourage public-private partnerships to address food safety problems.

California provides an excellent model for the kind of public-private partnerships that can help ensure the safety of the food supply. In 1996 and 1997, in the wake of two strawberry scares in California, we at the California Department of Food and Agriculture brought together government, industry, and university leaders to address the problem.

The result was the creation of the first of many Quality Assurance Plans, voluntary agreements that developed guidelines for safe food production and sound environmental practices. ...

Finally, USDA will strengthen cooperative working relationships with other agencies of government involved in food safety.

For instance, we at USDA were very pleased when Administrator Whitman announced that the EPA will re-establish a liaison to USDA. That position helps ensure that our respective agencies are working together toward our common goals, and not at cross purposes.

We know that it is possible to make good policy that incorporates all of these elements - and the Pathogen and Hazard Analysis and Critical Control Point system (HACCP) is an excellent example.

HACCP, as you know, has been fully implemented into the 6,700 federally inspected and 2,500 state-inspected meat and poultry plants nationwide, and the meat and poultry we import from other countries must be produced under a HACCP-based, equivalent system.

We know that HACCP is working. A new report from FSIS shows that the prevalence of Salmonella on raw meat and poultry products continues to decline - by as much as half on raw chicken, for example. We are seeing sustained reductions in foodborne illness as well, according to the newest data released from the Centers for Disease Control and Prevention. We are seeing more and stronger partnerships among industry, government, academia, and consumers. ...

Some today argue that to ensure the safety of the American food supply, the wisest course would be to isolate U.S. agriculture from the rest of the world. But food safety is a global issue, that demands a global response. Diseases and pathogens respect no national borders. That's why the wiser course is to work cooperatively with other countries on food safety and animal monitoring. We need to harmonize inspections and regulations at ports before diseases break out. We need to be as global as the pathogens. The work that has been ongoing for many years through the Codex Alimentarius Commission and the International Office of Epizootics is a good model for the future.

If one theme stands out in all this, it is cooperation.

Every sector of the food economy - every link in the food chain - needs to work together toward common solutions. Examples as varied as HACCP and California's Quality Assurance Plans show that when government, industry, scientists and consumers come together to solve problems, the results are policies that satisfy the interests of the various groups while promoting the public good.

I look forward to working with all of you to develop new approaches that further protect consumers and ensure that America's food supply remains the safest in the world.

Papers and Presentations
Curtis Kastner, Kansas State, presented a paper on "Product Shelf Life" in July at the American Association of Meat Processors annual convention in Nashville. In August, Kastner also delivered a presentation on "Meat Technology and Processing - Current Issues and Trends" at the 47th annual International Congress of Meat Science and Technology in Krakow, Poland.

Erdogan Ceylan, Daniel Fung, Melvin Hunt, and Curtis Kastner, all of Kansas State, presented a paper on "Synergistic Effect of Garlic, Cold Storage and Heating in Controlling Escherichia coli O157:H7 in Ground Beef Patties" in June at the annual meeting of the Institute of Food Technologists in New Orleans.

Donald Kropf, Kansas State, presented a paper on "An Update on Meat and Food Irradiation" in April at the Clemson University Food Safety Symposium.

Michael Johnson and James Denton, both of Arkansas, were invited participants in June at Tyson Foods' groundbreaking ceremonies for a $5.2 million 17,000-square-foot expansion of its Corporate Laboratory and Research Services Building in Springdale, Ark. Denton, director of the University of Arkansas Center of Excellence for Poultry Science, delivered an address on the importance of food safety and what the new facility will mean to students seeking internships in research. Johnson spoke on the UA food science department's history of involvement with Tyson's corporate lab since 1986. Denton and Johnson joined John Tyson, Tyson foods chief executive officer, and nine Tyson personnel in turning shovels on the site where construction would follow. Articles about Johnson's and Denton's participation were published in The Morning News of Northwest Arkansas and the Arkansas Democrat-Gazette.

James Denton, Arkansas, was named Man of the Year by the Poultry Federation at its meeting in June in Hot Springs, Ark. Denton has also been named director of the Poultry Safety Center, one of 12 virtual centers of the National Alliance for Food Safety. In March he attended the HACCP Alliance Board of Directors meeting in Atlanta. He delivered an invited presentation at the Poultry Symposium in April in Springdale, Ark. In May he traveled to Scotland with other faculty in the University of Arkansas International Agriculture Program where he discussed food safety issues and poultry research with faculty from the Avian Science Center in Auchincruive. Also in May, Denton attended the National Chicken Council's Animal Welfare Task Force meeting in Atlanta.

Food Safety Digest
By Dave Edmark
It's not uncommon to hear food safety advocates call for more consumer education. Researchers at Utah State University have come up with the proof to verify the need to concentrate more on what's going on in the kitchens at home.

Considerable effort is made in food safety research to find ways to avoid contamination during production and processing. But once the food lands in the home, consumers have ample opportunity to undo all the precautions that were taken up to the time of purchase.
According to a report in the newspaper Feedstuffs, the Food Safety Institute at Utah State went into the homes of consumers with video cameras and recorded what went on in the kitchens. Ninety-nine homemakers prepared an entree of chicken, fish or meat loaf and a salad before the cameras. The subjects were told that the video would be used to promote recipes, so presumably they would not feel self-conscious about their food safety habits.

They apparently didn't. The videos showed that the homemakers frequently failed to wash hands, or did so for only a few seconds. Of those who did wash their hands, only about one-third used soap.

They used cloth kitchen towels to dry their hands about two-thirds of the time, the same towel that was used to clean the utensils and pat meat dry. Almost all of them attempted to check the meat's doneness, but only 5 percent of them used a cooking thermometer, the only reliable way of determining if meat is fully cooked. About one-third of them kept their refrigerators warmer than the recommended level of 40 degrees Fahrenheit.

"It's like a black hole," said Janet B. Anderson, director of the Food Safety Institute. She suggested that food safety education should include repeated demonstrations and recommendations to prevent foodborne disease from occurring in the home.

* * *

So what to do? There is an abundance of resources for consumer education. One is on the U.S. Department of Agriculture Food Safety and Inspection Service web site. FSIS has divided the page into resources for consumers and for education and health professionals. Viewers will find copies of FSIS brochures and publications in addition to links to web pages highlighting various consumer education campaigns. The site has enough material for anyone to print hard copies and form a do-it-yourself consumer education program. All this is on line at

* * *

New brochures about irradiation are available in short question-and-answer formats. They are oriented toward consumers looking for basic introductory information about food irradiation.

The Minnesota Department of Health has published one of the brochures, titled "Irradiated Food - What It Means for You and Your Family." A PDF version of the brochure can be downloaded at

Pennsylvania State University has issued the other brochure called "Questions and Answers About Irradiation of Meats." The PDF version of this brochure is available at

Printed copies may be ordered from addresses listed on each brochure.

* * *
Tensions in Hong Kong between citizens and the mainland government have spilled over into food safety issues. In June, Reuters news service reported that the Hong Kong government was criticized when local health authorities waited five days before revealing that a beef sample from the mainland was contaminated with E. coli O157:H7. Government officials were quoted as saying they tried to recall the tainted meat when test results showed the contamination, but were told it
had already been sold. The government said there were no reports of any E.coli-related illnesses since the tainted beef went on sale so it was unlikely to have infected humans since the bacteria only has a gestation period of between three and nine days. Doctors, however, said E.coli-related health problems could lead to more serious illnesses which may not surface until later.

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