Articles in this issue:
Hog farmers can take advantage of HACCP data to reduce pathogen levels. (Photo courtesy of National Pork Producers Council)
Reducing the level of pathogenic bacteria in hogs on the farm is more than just a good health practice. The information on pathogen levels gathered on the farm can be useful for hog slaughterers and processors who receive herds of swine from the farm. Fine-tuning that information and determining how to apply it is the object of Stephen Gorton's work.
Gorton, a co-investigator with the Food Safety Consortium at Iowa State University, is attempting to determine some of the economic costs and benefits for farmers when they provide the slaughter facilities with a safer product - swine with reduced levels of Salmonella.
Gorton analyzes the costs of testing for Salmonella on the farm. Industry personnel may soon use data detailing the prevalence of Salmonella in swine herds for making management decisions such as arranging schedules to place swine herds in slaughter facilities at particular times of the day.
For example, swine herds with Salmonella at certain lower levels could be scheduled into slaughter facilities early in a production shift to reduce the likelihood of cross-contamination. Swine herds identified with higher levels of pathogens would be more likely scheduled into slaughter facilities at the end of the day or during the final shift to minimize cross-contamination for a subsequent herd, or immediately prior to cleaning the facility at the end of the last shift of the day.
In other cases, a procedure for processing herds of swine with exceedingly high levels of Salmonella could be to send the animals to a meat processing facility where pork products are made into cooked products or possibly to a rendering facility. Since there are greater economic advantages and profits for fresh meat, Gorton said, the animals are sent to the other facilities only when deemed necessary. Producers and slaughter-processors lose potential profits on devalued meat products.
So the determination of pathogen levels on the farm is becoming a key factor in processing decisions down the line, particularly with the implementation of the Pathogen Reduction Act, which will likely place swine producers under increased scrutiny in their role as suppliers to slaughterers and processors. Gorton wants to develop a process to test for Salmonella that would minimize the costs of microbial testing for swine producers and for slaughterers and processors that would meet industry's desire to have data within a 2 or 3 percent margin of error.
"Personnel testing for pathogens in slaughter and processing facilities sometimes take tests at random control points or critical control points to identify different types of pathogens and to quantify them at specific levels," Gorton said. "They do not necessarily perform tests in high enough volume or quantity to be statistically significant. In the past, microbial testing has at times been performed at convenience points - not necessarily at identified critical control points in the slaughter and processing facilities." This may be attributed to plant design and layout, product flow and process flow.
"You'll see changes regarding microbial testing, compliance and product integrity over the next year due to regulatory policy," Gorton said. "Note, however, that it is going to take some time to integrate these changes due primarily to industry infrastructure."
In surveying several swine slaughter and processing facilities, Gorton asked food safety and meat quality personnel to estimate the upper limit of Salmonella-infected swine they accept at their plants. On the average, they estimated the upper range to be 8 to 8 1/2 percent prevalence for a herd.
Some industry personnel stated that they want to lower the Salmonella level coming from swine producers to around 5 percent in the next two to three years. Slaughter-processors would need to know the overall health status for swine herds coming to the slaughter facilities. That information would be a logical part of the Hazard Analysis and Critical Control Points (HACCP) management systems that slaughter and processing facilities are implementing under new U.S. Department of Agriculture regulations. Under the science-based HACCP procedures, each slaughter and processing facility is responsible for finding critical control points in its specific processing system and for reducing levels of pathogenic bacteria at those points.
Gorton noted that estimates show as many as half or more of all hog producers currently do not have any formal data recorded for pathogens on the farm before sending herds to slaughter. Microbial testing is often done after the fact, when herd health status is suffering. Those producers who have HACCP plans and manage their on-farm data have the incentive of knowing their overall herd health status and their herd performances and cost differences, enabling them to make better management decisions in advance.
If HACCP management procedures and microbial testing on the farm reduce Salmonella, the result can be enhanced pig growth, reduction in time to market, efficient conversion of feed and lower production costs. The question becomes whether this is a sure sequence of events and whether this information can be used as a prediction tool.
"We are looking at standard swine production facilities that uses the same management, nutrition programs and genetics and are comparing those units by taking a closer look at economic advantages for producers," Gorton said.
Farmers who have HACCP plans and who conduct microbial testing find that their costs depend on the size of their operations. The cost per pig varies widely depending on how many pigs are in a herd or groups of herds. The costs range from 49 cents per head for a 10,000-head group to $5.37 per head for a 500-head group.
That situation has led to feedback from companies that market microbial test kits to the industry. Many such products are targeted at the high-volume slaughter processing industry, where the costs of gathering data are less. Marketing microbial test kits to lower-volume producers is hindered because there is a higher average cost to collect data in these cases.
"It is not necessary for a low-volume producer to triple output to have an effective HACCP management system for producing swine," Gorton noted. The idea is to help producers to better manage their herds. Producers who can tolerate a slightly higher risk level by having a working HACCP management system in effect can reduce their testing costs per head.
"That's what we're trying to build or model into this work," Gorton explained. "We are looking at different risk acceptance levels for producers and incorporating that information into this work which can be used by producers when implementing or maintaining a HACCP plan."
KSU's Daniel Fung (left): Heat kills E. coli, enhances fermentation process.
Food preservatives often include the use of acidic chemicals. That process can have its down side: Increased acidity can result in greater tolerance of the acid by pathogenic bacteria such as E. coli 0157:H7. But heat can provide a way around that problem.
At Kansas State University, researchers with the Food Safety Consortium looked into the situation by experimenting with salami. They found that heat treatment after fermentation can reduce the E. coli 0157:H7 levels.
Without heat, microorganisms have the ability to adapt to acid and tolerate it, said Daniel Fung, a Food Safety Consortium principal investigator and professor in KSU's animal sciences and industry department. "That could be dangerous because some cells, if you put them in acid, will die. But if they are slowly adapting to the fermentation on the tail end you may have some that can survive."
So if the acid being used as preservatives can be made faster, the microorganisms may not have time to adapt to it and they are more likely to be killed, Fung said.
The use of heat treatment after fermentation to kill more E. coli 0157:H7 bacteria negates the problem of acid prolonging the bacteria's survival. "If the cell is adapted to acid they are more liable to be killed by heat," Fung said.
Some foods, such as certain sausages, don't receive heat treatments because of the nature of their processing. Those foods go through only the fermentation process. Fung's team is looking into the possibilities for those products.
"We are doing some sausage fermentation without heat treatment," he said. "So at these low temperatures, acid fermentation may be a problem but we don't know for sure yet. We are also doing some research on fermentation with a 55-degree Celsius heat treatment. If you do that, you kill the cell much better."
The sausage experiments are important because the federal Food Safety and Inspection Service wants sausage manufacturers to verify that their processing procedures can eliminate the pathogen. The agency requires that tests on the sausages be conducted by inoculating them with 10 million units - 107 units - of E. coli 0157:H7 and then show that the fermentation process reduces the pathogen to 100 units, or 102. Going from 107 to 102 is called a reduction of 5 logs, the level of reduction that FSIS wants to see accomplished in tests.
"We can achieve only a 1- or 2-log reduction by fermentation alone, so a little bit of heat treatment at the end can help us a lot," Fung said.
To close the gap and kill the remaining bacteria inoculated into the sausage, the KSU team is trying to determine if it can reach the goal by starting with some acid treatment in the meat followed by fermentation and ending with a small amount of heat.
Chef Artichoker is thawing the Thanksgiving turkey at room temperature. The evil Petri J. Contaminator threatens to infect it with vile bacteria. Food safety superheroes Cooker and sidekick Mini-baster save the day-and Thanksgiving dinner!
A new Saturday morning cartoon? No, a Web-based comic strip that contains an important lesson in food safety.
The comic strip is part of a food safety curriculum "Safe Food: It's Up to YOU!" designed specifically for young people by Peggy Sherry, a research associate in Iowa State University's Extension to Families. The curriculum is being piloted in food service and nutrition courses at 15 Iowa high schools.
In the comic strip, Chef Artichoker, owner of Artichoker's Café, learned a valuable lesson from Cooker and Mini-baster: the Thanksgiving turkey must be thawed in a sink with cold water that is changed every 30 minutes or it can be contaminated with foodborne pathogens.
"Most food safety education efforts target an adult audience," said Sherry. "We are missing a crucial opportunity to educate our young people about the dangers of foodborne illness and the power they have in preventing them."
The curriculum's four lessons are presented in simple language and are accompanied by colorful artwork.
Each lesson is followed by an achievement test, which students complete and check against the computer. If their answers are incorrect, they must repeat the lesson. Once they have completed all four lessons successfully, the computer enables them to print a certificate of completion to be signed by their instructor.
A turkey named "FAT TOM" guides students through the characteristics of food in lesson four. Each characteristic begins with a letter in FAT TOM's name: Food, Acidity, Time, Temperature, Oxygen, and Moisture. FAT TOM even raps for those using computers with sound capabilities. Fat Tom is based on a lesson in the National Restaurant Association's ServSafe program.
"Let's face it, food safety isn't a real flashy topic," Sherry said. "Our curriculum was designed to bring food safety education to life. If students remember FAT TOM or Petri J. Contaminator, chances are good they'll remember the lessons behind them."
Teachers in participating schools will evaluate the Web-based curriculum and provide feedback to Sherry and fellow researchers Jim Huss and Pat Redlinger, both ISU families extension program specialists.
The curriculum is part of a larger food safety education initiative funded by the United States Department of Agriculture. Sherry, Huss and Redlinger have designed an extensive food safety Web page network with information on everything from packing food safely at tailgate parties to 10 steps consumers can take to keep their kitchens safe from foodborne illness. The group has also designed educational displays and materials for a variety of audiences.
"Over the past few years, consumers' confidence in regulatory agencies has been shaken a bit," said Sherry. "Through this project, we hope that consumers of all ages will begin taking a more active role in protecting themselves from foodborne illness."
The ISU Food Safety Website can be found at: http://www.exnet.iastate.edu/Pages/families/fs/homepage.html. Visitors to the site will find a link to the food safety curriculum "Safe Food: It's Up to YOU!"
The daily work performed by the Food Safety Consortium's researchers never fails to be relevant. The value of the work becomes more apparent to the American public on those infrequent occasions when food safety issues take center stage in the media spotlight. For several days late this summer, we witnessed events unfold after Hudson Foods recalled millions of pounds of ground beef upon learning of the presence of E. coli bacteria in some of its patties. During that period, several of our Consortium's researchers were contacted by reporters across the nation looking for background information about pathogenic bacteria, HACCP, production and processing.
It is no surprise that people looking for expertise in this subject would turn to our three universities' researchers to gain some perspective. The Consortium's efforts are of major interest to industry stakeholders and government.
For example, the recent ground beef recall brought to the forefront discussion of irradiation. Consortium investigators at Kansas State University and Iowa State University have been spent years studying the applicability of this process to beef and pork. The results have been encouraging and their findings have contributed to the body of knowledge on the subject that the U.S. Department of Agriculture and the Food and Drug Administration have taken under consideration in determining whether to approve the use of irradiation for meat processing.
The prominence of ground beef in the news called attention to research at Kansas State of major importance to consumers. Our team there found that premature browning of burgers could mislead cooks into thinking that their burgers are done when in fact they may not yet be thoroughly cooked. The KSU findings were incorporated into USDA recommendations that cooks must use a meat thermometer to be sure that any pathogens in the meat have been killed. KSU has also worked closely with industry to implement steam pasteurization of beef cattle carcasses in processing plants as way to kill surface bacteria.
University of Arkansas food scientists are examining bacteriocins, organisms that inhibit the growth of harmful bacteria. The use of bacteriocins as food preservatives will be helpful in fighting foodborne disease in minimally processed refrigerated foods.
Several of our researchers at the University of Arkansas, Iowa State and Kansas State focus on potential health problems for animals on the farm. They continue exploring ways to reduce the risk of bacterial contamination that livestock and poultry face before moving on to the processing plants.
These are just a few examples among many available that demonstrate our Consortium's focus on contemporary food safety problems. Research such as this is for the long haul, not the quick fix. The effort of these researchers becomes a part of the literature and procedures of food production and processing. Its value becomes obvious in the aftermath of a crisis, but its usefulness is realized every day as a nation of consumers, producers and processors go about their routines.
A poultry vaccine that could reduce the incidence of salmonella-tainted eggs has been developed by an Iowa State University researcher. Veterinary microbiologist Theodore Kramer, a principal investigator with the Food Safety Consortium, said the vaccine could improve food safety.
The vaccine prevents hens from spreading salmonella to their eggs. It also significantly reduces the likelihood of the bacteria spreading to other chickens through feces, Kramer said. Use of the vaccine by egg producers still requires additional tests and U.S. Department of Agriculture approval.
The vaccine targets bacteria called Salmonella enteritidis, organisms which cause food poisoning in humans called salmonellosis. The bacteria are found in the intestinal tracts of animals and humans and are easily spread. They hospitalize thousands in the United States annually and can cause death, according to Kramer.
He added that chicken eggs account for about half of the U.S. human salmonellosis cases.
Kramer developed the vaccine using technology similar to what he and another ISU researcher used five years ago to create a swine salmonellosis vaccine. Both vaccines use live salmonella bacteria that have been stripped of their disease-causing capabilities. The new vaccine is administered to hens in their drinking water.
Kramer has been working on the poultry vaccine since 1995.
The vaccine could benefit egg producers around the world because salmonella-ontaminated eggs are a global problem. Egg-borne human salmonellosis is most common in the United States along the East Coast.
"Salmonella costs the United States $2.5 billion a year," Kramer added.
Iowa is among the nation's top five egg-producing states, according to Janet Anderson, executive director of the Iowa Egg Council in Ames. She said Iowa has 20 million laying hens that produce 5.5 billion eggs annually. Anderson also said the Iowa egg industry is growing rapidly.
Humans who contract salmonellosis from eggs usually do so by eating products such as ice cream, mayonnaise or salad dressing made with contaminated raw eggs. Salmonellosis symptoms include attacks of abdominal cramps, nausea, vomiting and diarrhea. The attacks may be more serious for infants, pregnant women, the elderly and the ill.
"The effects of salmonellosis can be far-ranging," Kramer said. "A contaminated food product produced in a large quantity and distributed widely can cause illness in several states.
"Salmonellosis is normally not a health problem for consumers who properly store and cook their eggs," Kramer said.
Kramer said it is important to keep chicken flocks from being infected with Salmonella Enteritidis. The bacteria are difficult to detect in chickens. Infected hens usually do not appear ill and current tests for the bacteria are time consuming and costly, Kramer explained.
"In a unit of 10,000 hens, it would be difficult to test every bird," Kramer said. "If salmonellosis is found, about all the producer can do is destroy all of the hens. That can be financially ruinous to the producer."
ISU has applied for a patent for the vaccine.
The battle against foodborne disease is fought on many fronts, especially against pathogenic bacteria in meat. Those who work with pork products start the process by attempting to reduce pathogens in living animals. Progress is being made in that area, although elimination of pathogens from raw meat and meat products is still an elusive goal.
"To the extent that we can reduce pathogens before they get into the packing plant for those animals that are carrying organisms, the better off we are at the packing plant," explained Dr. George W. Beran, the program director for the Food Safety Consortium at Iowa State University. "But these organisms do multiply in the environment that comes in with the animals. That's where sanitation comes in very strongly."
Pathogenic microorganisms that are found on live animals, meat and poultry and their products may originate from these sources:
* The living animals themselves, who may appear to be healthy but are carrying bacteria that are harmful to people;
* The environment of the slaughter, fabrication or processing plant, which may contain organic mater or which may be the site of cross-contamination from humans or animals;
* Humans who handle animals, carcasses, or meat and poultry.
Management practices can greatly reduce the level of Salmonella infections during the early stages of a pig's life, Beran said. Segregation of the pigs during their early weaning stages makes them a sanitized disinfected unit.
But difficulties can arise as the pigs grow. "Some will remain Salmonella free and others will not," Beran said. "We are just in the process of trying to learn what are the levels of prevalence of infection of other organisms."
Beran listed those organisms as Yersinia, a swine carried bacterium; Clostridium and Listeria monocytogenes, which are environmental organisms found in swine; and Staphylococcus aureus, a human carrier organism.
The essentials of preventing infection on the farm include determining that all feeds are free of Salmonella; control of personnel working in production units; control of animals, birds and insects to prevent any contact with production animals, and the prevention of infectious and parasitic diseases which could enhance Salmonella infections in the animals.
The environment on the farm plays a major role in the pigs' health. A stressful environment on the farm can enhance the pigs' shedding. Reduction of shedding and infection levels on the farm would reduce the levels of pathogens on pigs entering marketing and processing channels, Beran said.
The slaughter process itself increases the stress on animals as they spend several hours in holding pens, and leads to more shedding and potential infection. Beran noted that some newer packing plants are getting around this problem by moving pigs from the farm directly to the plant over a relatively short distance so the pigs spend only a matter of hours or even minutes in transit rather than days. "Then you move them right into slaughter as they're unloaded," he said.
Much of the effort to reduce contamination is still directed to phases of processing and packing after slaughter of the pigs. "But to the extent that we can reduce pathogens before they get into the packing plant for those that are carrying organisms, the better off we are at the packing plant," Beran said. "But these organisms do multiply in the environment that comes in with the animals. That's where sanitation comes in very strongly."
As long as animals coming into the plant with varying levels of pathogens are butchered together, Beran said, "I don't see that we are going to be able to get control of the organisms that come into the plant with the animals and then multiply within the environment on meat and on the animal tissues." But reducing those levels would still be "a tremendous move forward" that can be accomplished through continuing efforts to make processing facilities as sanitary as possible and keeping carcasses free of contamination.
The safety of ground beef will continue to be best insured by thorough cooking to prevent contamination by the pathogenic E. coli 0157:H7 bacterium. The problem, Beran said, is that ground beef is made from the trim of the tissue. "It means ultimately that when we grind the product, the whole product all the way through is surface (the most contaminated portion) because we have mingled organisms all the way through it."
Cooking and irradiation are the two possible solutions to insuring ground beef's safety. Beran sees irradiation as a significant measure to be used on ground beef patties because the product then has a uniform thickness and irradiation beams can be spread through it. "In the meantime, I feel we must place some emphasis on cooking of ground products."
For cuts of meat and whole meat, The best insurance
remains the butchering only of healthy animals. "Protection
of pork can be achieved only on the farm," Beran said. "If
infected swine enter slaughter, terminal inactivation of these
pathogens is needed to prevent transmission to consumers."
Remarks prepared for delivery by Dr. Catherine Woteki, Under Secretary for Food Safety,before the Ceres Forum of the Center for Food and Nutrition Policy and the American Association of Veterinary Medical Colleges, Sept. 25, 1997, Georgetown University,Washington D.C.
I'm pleased to be here with you this morning to talk about food safety, E. coli, and, specifically, about E. coli O157:H7. My remarks will focus primarily on E. coli in meat products, although the pathogen is affecting a larger spectrum of the food supply.
I can attest firsthand to the power this microorganism exerts on public health officials such as myself, as well as on the public psyche. Just two weeks after I was confirmed as Under Secretary for Food Safety, I was on national television discussing the largest recall of ground beef in USDA history because of contamination with E. coli O157:H7.
If you consult a textbook of microbiology, you would find out that E. coli is a gram negative,rod-shaped bacteria belonging to the family Enterobacteriaceae, and that E. coli O157:H7 is a pathogenic strain that produces large quantities of two toxins that can cause severe damage to the intestinal lining and other organs. You would also probably read that it doesn't take very many organisms to make someone sick--perhaps 10 or fewer organisms could seriously harm an individual.
What the textbook won't tell you is how E. coli O157:H7 is responsible for changing the nation's mind set about foodborne pathogens. Such a tiny organism, but such a large impact. Less than a decade ago, the pervasive attitude among industry--and even among some regulators -- was that bacteria, including pathogens, are a natural part of the environment and can't be controlled. The idea that government would begin setting standards for pathogen reduction, and testing raw products for bacteria contamination, was beyond belief. And the idea that industry would begin to embrace HACCP as good business was a reality only among the most progressive industry leaders.
But that's exactly what happened. It didn't happen overnight. It was a gradual awakening that began with emerging scientific data about pathogens and a growing realization that the meat and poultry industries have changed. Foodborne pathogens are not new. As early as 1830, Trichinella spiralis was recognized as causing foodborne disease.
I believe USDA is making significant progress in its fight against foodborne illness. Shortly after the 1993 outbreak, USDA issued a rule, after overcoming an industry legal challenge, requiring safe handling labels that address storage, cooking, and holding practices for raw meat and poultry products.
In 1994, after withstanding another legal challenge from industry, USDA established E. coli O157:H7 as an adulterant when present in raw hamburger and initiated a monitoring program for the pathogen in ground beef. We currently test over 5,000 raw ground beef samples per year from plants and retail locations.
In 1996, after a thorough public process, USDA published its landmark rule on Pathogen Reduction and Hazard Analysis and Critical Control Points (HACCP). That rule requires all plants that slaughter and process meat and poultry to implement HACCP systems as a means of preventing contamination from pathogens and other hazards. The preventive approach that is embodied in HACCP is an important principle in our fight against pathogens, because we all know you cannot ensure the safety of a product through testing. Prevention must be our first line of defense.
To make sure HACCP systems are working as intended, the rule also sets in-plant performance standards for Salmonella, and the Food Safety and Inspection Service (FSIS) will conduct testing to ensure these standards are being met. Indeed, this is a very significant step, because it is the first time USDA has set a performance standard for a broad range of raw meat and poultry products.
Because Salmonella, E. coli O157:H7 and other pathogens are associated with fecal contamination, the rule also requires slaughter plants to routinely test carcasses for generic E. coli, an indicator of fecal contamination. And the rule requires all plants to have in place standard operating procedures for sanitation.
Despite our progress, we continue to face many challenges in the years to come.
A major challenge for the future is having enough, and the right type of, information on which to base regulatory decisions and develop new prevention strategies. On a very basic level, we must encourage fundamental research on the natural history of human pathogens in animals. We need to know, for example, how these pathogens develop disease-resistance and how they acquire the ability to produce toxins. This fundamental science will set the stage for potential breakthroughs in vaccines and other preventive approaches.
It's clear that scientific knowledge has not reached the point where we can say, with any certainty, what practices will reduce microbial pathogens in animals before slaughter. But we are seeing some progress. And epidemiological research to trace the problems we are having with E. coli O157:H7 and other pathogens back to their sources will be useful in our efforts to develop effective prevention strategies on the farm, in feedlots, and other intermediate stages before animals reach the slaughter plant.
We also need research to help us make regulatory decisions that are based on the most current science. HACCP provides an important framework for improving food safety within plants, but it must be combined with science-based performance standards that HACCP systems are designed to achieve. Through the HACCP rule, we have taken the first steps toward setting science-based performance standards for pathogens based on the levels of Salmonella currently found in various products. But our ultimate goal is to base performance standards on quantitative risk assessments. We need extensive, new data to conduct these risk assessments.
That is why we are extremely interested, and involved, in food safety research and development. FSIS is not a research agency. But it certainly has an important role in identifying research needs to fill critical data gaps. As Under Secretary for Food Safety, I will ensure that regulators, consumers, producers, researchers and processors work closely together to identify research priorities.
Another major area where we need to do a lot more work is in educating those involved in producing, transporting, and preparing food, including consumers. The mind set on pathogen reduction may have changed, but not everyone is on board.
For instance, we need to do a better job of changing food safety behavior in the home. It's not enough to provide information--we must be able to change behavior. In June, USDA, in cooperation with FDA and CDC, sponsored a conference here at Georgetown University as a means to share information on changing food safety behaviors. We will soon announce a new education campaign for consumers that is the result of government and industry working together.
We also need to make sure industry is on board when it comes to taking responsibility for food safety within their own operations. Mandatory HACCP and performance standards for Salmonella provide an incentive for plants that slaughter and process meat and poultry to implement process control systems, but what about the rest of the industry not subject to this regulation?
Market forces will have some influence. We are already seeing retailers place pressure on their suppliers to have HACCP systems and to test products for contamination, and we believe such market forces will lead to change at all levels of the farm-to-table chain. But we also need to rely on education as a means of encouraging those involved in producing, transporting, and preparing food to follow good manufacturing practices. I hope the veterinary community will do its part at the animal production level.
The President's Food Safety Initiative, which was announced on Jan. 25 of this year, will help us to meet many of these challenges on a government-wide basis.
I will be working closely with the Department of Health and Human Services and the Environmental Protection Agency to see that those initiatives receive funding and are put into place. We're also working together to prepare an FY 1999 budget initiative on food safety.
I would like to close with a word of caution. This conference focuses heavily on E. coli O157:H7, but we must be careful not to lose sight of the many other foodborne pathogens that are already here and those with new disease-causing capabilities that have yet to emerge. Certainly, E. coli O157:H7 has been on center stage for the past several years, but finding a set of specific actions to address this specific pathogen is not the answer to foodborne illness.
The challenge, for regulators, industry, and academia, is to develop a comprehensive approach that addresses all known pathogens, and to be constantly vigilant to emerging ones. I believe we have made significant progress, but this certainly is no time to relax. As a case in point, outbreaks of E. coli O157:H7 are now associated with radish sprouts and lettuce--newly recognized vehicles for the transmission of the pathogen. We have a lot of work ahead of us, and we must work together in a coordinated fashion to make real progress. I look forward to working with all of you to meet our mutual goal of reducing the incidence of foodborne illness.E. coli O157:H7, but we must be careful not to lose sight of the many other foodborne pathogens that are already here and those with new disease-causing capabilities that have yet to emerge.
Certainly, E. coli O157:H7 has been on center stage for the past several years, but finding a set of specific actions to address this specific pathogen is not the answer to foodborne illness.
The challenge, for regulators, industry, and academia, is to develop a comprehensive approach that addresses all known pathogens, and to be constantly vigilant to emerging ones. I believe we have made significant progress, but this certainly is no time to relax. As a case in point, outbreaks of E. coli O157:H7 are now associated with radish sprouts and lettuce--newly recognized vehicles for the transmission of the pathogen. We have a lot of work ahead of us, and we must work together in a coordinated fashion to make real progress. I look forward to working with all of you to meet our mutual goal of reducing the incidence of foodborne illness.
By Doug Thompson
Slogans have claimed for years that mouthwash and breath lozenges kill germs on contact.
The advertisements are right, researchers for the University of Arkansas for Medical Sciences have concluded. So why not use the same active ingredient to kill germs before they get in people's mouths and cause food poisoning?
"It looks obvious, after the fact. One of our biggest surprises was that nobody had a patent for this already," said Philip J. Breen, associate professor of pharmaceutics at the university's Biomedical Research Center in Little Rock. Breen and biopharmaceutical science associate professor Cesar M. Compadre led the research that now claims Cetylpyridinium chloride is the best agent to clean meat.
The University of Arkansas system has taken out the patent on the methods, strengths and concentrations worked out by Breen, Compadre and fellow researchers -- six years of testing funded by the university and the nonprofit Food Safety Consortium.
Compadre and Breen will form a company -- tentatively named Bacto Stat -- to market the idea to poultry processing companies, and to develop further uses of the odorless chemical on fruits, vegetables and other foods. The company will pay the university a fee for use of the patent, and a portion of any commissions.
Cetylpyridinium chloride destroys 99.99 percent of all germs on poultry -- and does not affect food texture or taste when used in the right concentrations, Breen and Compadre contend. Commonly known as CPC, the chemical can replace the chlorine in water used to clean poultry without requiring replacement of existing sprayer equipment.
Chlorine is only 90 percent effective against germs, Compadre said. Unlike chlorine, CPC is not a cancer-causing agent, which led to a ban on chlorine-cleaned chicken in Spain, Portugal and other European countries.
"It was one of those rare cases where the best theoretical option for the job also appears to be the best commercial option," he said.
Six years of research were needed to find the right chemical, prove its effectiveness and find the right methods, according to Breen and Compadre.
"That's where the Food Safety Consortium really has its role," Breen said.
The consortium is a food-related research group consisting of the University of Arkansas, Iowa State University and Kansas State University. The Arkansas university team studies poultry-related problems. Iowa studies pork issues and Kansas studies beef. All the researchers share information.
The consortium's goal is to find ways to improve food safety above and beyond what the government requires, and do it at the lowest possible cost. This requires a long-term commitment to basic science and to cooperation that private, competing companies usually cannot afford, Breen said.
"It's an exciting time to be working in this, because the theoretical work is just beginning to result in applications we can put into use," Breen said. Also, methods worked out by the consortium already have the basic science and testing work done, the type of testing that can hold up regulatory approval of a new safety technique for years.
Everybody looks for "magic bullet" cures, Compadre said.
"Instead of a magic bullet, you need the whole gun," he said. "The academic community has realized that it has to make some money to have the wherewithal to do the research," Breen said.
"Grants and contracts are drying up, and National Institutes of Health support is getting harder and harder to get." What's left should rightly go to AIDS and breast cancer research for example, he said.
"You don't want Harvard University researching poultry food safety, even if you could get them to do it," Breen said. "The expertise and the industry is here."
(This article appeared in the Sept. 24, 1997, edition of the Arkansas Democrat-Gazette. It is reproduced with permission.)
Randy Phebus and his fellow researchers at Kansas State University wanted a thorough check to make sure that slaughtered beef cattle carcasses weren't registering any traces of pathogenic E. coli 0157:H7 bacteria. So they ran 400 carcasses through the steam pasteurization process that KSU developed and they came out clean.
Phebus, a Food Safety Consortium principal investigator at KSU, has been conducting long-range research on the capabilities of steam pasteurization and its applications for industry. In recent studies, the research team has explored wider areas of the carcasses. Previously, researchers removed only core samples of tissue from one location on the carcass. But the question remained whether steam pasteurization - a 6- to 8-second immersion in pressurized steam that raises the carcass surface temperature to 185 degrees Fahrenheit - was actually covering the entire carcass and killing bacteria uniformly.
Monitoring bacterial levels throughout the carcass, the team found they had a uniform kill rate. Then the scientists moved on to using a new sponge sampling technique that evaluates tissue from larger areas of the carcass ranging up to 300 square centimeters.
"We could show that with steam pasteurization, it's going to be almost impossible to fail the E. coli standards because we never found a carcass that was even close to missing," Phebus said. "And we did 400 carcasses."
Meanwhile, some in the processing industry had questioned the necessity of a federal regulation mandating that samples be taken from three sites on the carcass. "Our research shows that there is significant difference in microbial populations between those different anatomical locations on the carcass," Phebus said. "One sampling site is not sufficient. You need to maintain those multiple sampling sites. And the USDA has come out and said they are maintaining those sampling sites."
Additional research showed that levels of bacteria did not increase on the carcasses 24 hours after they underwent steam pasteurization. The use of certain other treatments on carcasses, particularly organic acids, could potentially injure cells. "After a time they could recover and still cause problems," Phebus explained. "So what we wanted to do was see after 24 hours if those counts of injured cells had come up a bit or if there was any resuscitation of the organisms."
The team discovered that the scenario didn't happen. They also found that once the steam pasteurized carcasses were placed in the cooler, the carcasses were not recontaminated by the air or the handling in the plant. But that situation can vary from plant to plant, he noted.
A computerized control panel tracks the progress of carcasses being treated in the system. Summary sheets show how many of the carcasses were processed to the proper temperature and how many were missed and which ones. "So you can tell how well the equipment or the process is running," Phebus said.
Studies of the results of the steam process showed that there were no differences in the bacterial populations of cows from fed cattle. Researchers wanted to see if there was a difference in the ability of steam to kill bacteria on fat-covered carcasses as opposed to the leaner tissue of cow carcasses, to which bacteria may attach themselves more easily.
Although steam-pasteurized carcasses can still be recontaminated after the process is completed, the application still keeps the risk of recontamination down from what they would have been if no steam had been applied. "We've always said that we're doing steam pasteurization at the carcass level," Phebus said. "It's just putting in a big hurdle. It reduces risk of enteric pathogens."
The biggest source of enteric pathogens is the animal's hide and its intestinal tract, all of which is removed during the slaughter operation. So as further processing continues, "the chances of recontaminating with those particular types of organisms are extremely reduced." Phebus explained that total elimination is not necessarily going to happen because a worker in the plant with a bacterial infection could spread it to the carcass.
"As long as you can isolate the slaughter floor from the further processed floor and keep people from tracking and prevent air exchange, you have greatly reduced the risk of those enteric type pathogens," Phebus said. Pathogens carried by humans, such as Staphylococcus, and environmental contaminants such as Listeria remain potentially as problems.
Steam pasteurization remains the most effective procedure for reducing bacterial contamination on wide areas of the carcass. Organic acids have been tested but the spraying does not easily cover the entire carcass inside and out. Also, E. coil 0157:H7 and certain other organisms are naturally resistant to organic acid, Phebus said. Hot water has been tried, but up to 200 gallons of water per head of cattle needs to be recycled while only 3 gallons per head are used in steam pasteurization.
Steam pasteurization is gradually gaining more recognition in the U.S. About 30 units are to be installed in processing plants around the nation by mid-1998. All of the Excel beef slaughter facilities are currently fitted with steam pasteurization equipment. IBP recently announced plans to install the units in all of their facilities.
"Those are the big ones that can do up to 400 head per hour," Phebus said. "We are very far along and have actually installed the first small unit for small processors that will do 30 head per hour."
The smaller processing units are more suited for European plants. Phebus, who met with government and industrial officials in Europe earlier this year, said European agricultural ministries are increasingly interested in steam pasteurization. The level of interest there is greater than that in the U.S., Phebus said, owing largely to the smaller size of the European beef industry and its ability to adapt to new practices faster than their counterparts in the U.S.
"It's like a scenario in the ocean," Phebus said. "If you're driving the USS Nimitz or you're driving a speedboat, which one can you turn around faster?"
John Marcy, Arkansas, served as moderator for the Poultry Science Association/Food Safety Consortium-sponsored symposium "Food Safety - A Consumer's Perspective." Marcy was also interviewed in August by KFSM-TV in Fayetteville, Ark., for background on Tyson Foods acquisition of Hudson Foods.
Michael Johnson, Arkansas, presented a paper on "Biotechnology and Food Safety Issues" in September to the Arkansas Biotechnology Association annual meeting and conference in Little Rock.
Johnson was also interviewed by several news media outlets in the aftermath of the Hudson Foods ground beef recall in August and September. On Aug. 22 he was interviewed on the 5, 6 and 10 p.m. newscasts of KHOG-TV in Fayetteville, Ark., about the Consortium's work on detection of enterohemorrhagic E. coli and proper cooking of hamburgers. He was interviewed by telephone Aug. 22 by a reporter from the CBS Evening News in New York on preparation of ground beef. Johnson was also interviewed by the Associated Press in New York about the Hudson Foods recall, by the Northwest Arkansas Times in Fayetteville about food safety and the disinfection of raw vegetables and fruits, and by the Arkansas Democrat-Gazette in Little Rock concerning his remarks to the Arkansas Biotechnology Association.
Johnson and Ramakrishna Nannapaneni, Arkansas, presented a white paper in September on "Piezoelectric and Surface Plasmon Resonance (SPR)-Based Biosensors for Detecting Foodborne Pathogens" to an NSF-FDA-USDA-sponsored Workshop on Enhancing Food Safety Through the Use of Sensors in Washington.
Johnson, Rong-Fu Wang and Debra K. Winters, Arkansas, published "Polymerase Chain Reaction (PCR) and Nucleic Acid Amplification Methods," Chapter 9, pages 183-205, in Food Microbiological Analysis - New Technologies, edited by M.L. Tortorello and S.M. Gendel, published by Marcel-Dekker, Inc., of New York.
Philip Breen and Cesar Compadre, University of Arkansas for Medical Sciences, were featured in an article in the Arkansas Democrat-Gazette in Little Rock about their research on Cetylpyridinium chloride.
Breen, Hamid Salari and Compadre, University of Arkansas for Medical Sciences, published "Elimination of Salmonella Contamination From Poultry Tissues by Cetylpyridinium Chloride Solutions" in the Journal of Food Protection, Vol. 60, No. 9, pages 1019-1021.
Curtis Kastner, Kansas State, will represent the university at the Beef Safety Symposium Dec. 3-4. Kastner will serve as a breakout session coordinator. The symposium is being organized by the National Cattlemen's Beef Association and the American Meat Science Association.
Elizabeth Doyle, Kastner and Jack Riley, Kansas State, have received a $45,864 grant from the Kansas Department of Agriculture to fund a position for HACCP assessment development and implementation in Kansas.
Sharon Luchsinger, Donald Kropf, E. Chambers IV, Claudia Garcia Zepeda, Melvin Hunt, S.L. Stroda, M.E. Hollingsworth, James Marsden and Kastner, Kansas State, published "Sensory Analysis of Irradiated Ground Beef Patties and Whole Muscle Beef" in the Journal of Sensory Studies, Vol. 12, No. 2, page 105.
Garcia Zepeda, Kastner, John R. Wolf, John E. Boyer, Kropf, Hunt and Carole Setser, Kansas State, published "Extrusion and Low-Dose Irradiation Effects on Destruction of Clostridium sporogenes Spores in a Beef-Based Product" in the Journal of Food Protection, Vol. 60, No. 7, pages 777-785.
R.K. Prasai, Kastner, P.B. Kenney, Kropf, Daniel Fung, L.E. Mease, L.R. Vogt and D.E. Johnson, Kansas State, published "Microbiological Quality of Beef Subprimals as Affected by Lactic Acid Sprays Applied at Various Points During Vacuum Storage" in the Journal of Food Protection, Vol. 60, No. 7, pages 795-798.
H.M. Stahr, Iowa State, received a $13,000 grant from Texas Cattle Feeders for toxicity studies of fats.
At the Midwest AOAC meeting in June in Fargo, N.D., Stahr, P.M. Imerman, T. Sun and G. Munkvold, Iowa State, presented a paper on "A Method to Analyze Commodity Samples for Fusiproliferin." Stahr, R. Moore and M. Domoto presented a paper on "Interlaboratory Studies of Mycotoxin Reference Samples. At the AOAC II meeting in San Diego, Stahr, Sun, Imerman and D. Schrunk presented a paper entitled "Preliminary Studies With Method development for Advantage in Biological Samples."
Irradiation of meat has received increased attention since Hudson Foods recalled ground beef during the summer after reports that some patties contaminated with E. coli 0157:H7 came from its beef processing plant. The U.S. Department of Agriculture and the federal Food and Drug Administration have been reviewing whether to approve the use of irradiation in beef processing.
Irradiation has been under study by Food Safety Consortium personnel for the past few years. The researchers' findings have been reported in scientific publications at various times and have become part of the literature of the subject.
Irradiation preserves food by exposing products to high-energy ionizing radiation. The radiation energy changes the molecules, resulting in the killing of microorganisms that could cause spoilage or illness.
At Iowa State University, investigators in 1994 published summaries of their studies on the dosage of irradiation required to reduce by 10-fold the levels of pathogenic bacteria in meat. They found that for the major foodborne bacteria - Salmonella, Campylobacter, Listeria, Yersinia and Escherichia coli 0157:H7 - the required dosages were 0.04 to 0.6 kiloGrays, well below both the maximum dosage levels allowed for poultry and the levels currently being sought for beef, pork and lamb. The World Health Organization considers any food irradiated up to an average dose of 10 kiloGrays to be wholesome and safe for consumption.
Low-dose irradiation killed the spores of Clostridium bacteria that remained in vacuum packaged beef-based snack sticks after the sticks were exposed the extrusion cooking process at Kansas State University. Clostridium botulinum bacteria are pathogenic and can grow on the beef if its bag is abused. In the experiment, nonpathogenic Clostridium sporogenes bacteria were used, but they are as difficult to kill as the pathogenic bacteria. The cooking process had already killed many of the spores. Those surviving spores that were injured could could potentially endanger the snack stick, but irradiation at 3.5 kiloGrays delivered the final blow and left no culturable Clostridia remaining.
Kansas State also examined irradiation's effects on the quality of certain meat: boneless pork chops, beef steaks, pre-cooked ground beef patties and raw ground beef patties. The research team in 1995 found that irradiation did not adversely affect traits such as color, product life, flavor and aroma. Professional flavor profilers assessed the beef steaks for attributes of texture and flavor and found little to no difference between irradiated and nonirradiated steaks. A panel of consumers reviewing boneless pork chops observed no differences between irradiated and nonirradiated samples while evaluating the chops' qualities.
The University of Arkansas conducted two studies regarding acceptance of irradiated products. A survey that brought responses from 556 food service profefessionals in 1996 identified 67.2 percent as willing to purchase irradiated broiler portions and 67.5 percent as willing to purchase irradiated beef patties if they were sold at the same prices paid for USDA-inspected products. A study in 1994 surveyed 600 households and found that 56.7 percent were willing to pay an average added price of 54 cents for irradiated chicken, 51 cents extra for pathogen-screened chicken and 78 cents additional for organically grown chicken sandwiches.
Iowa State researchers test marketed irradiated chicken at two supermarkets in Kansas in a 1996 study that showed about 30 percent of customers were willing to pay a premium for the product. The marketing included point-of-sale advertising and providing free samples.
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