Food Safety and Ionizing Pasteurization
Testimony Presented by
Michael T. Osterholm, Ph.D., M.P.H.
State Epidemiologist and Chief Acute Disease Epidemiology Section
Minnesota Department of Health
717 Delaware Street Southeast
P.O. Box 9441
Minneapolis, Minnesota 55440-9441
Presented to the
Senate Committee on Agriculture, Nutrition and Forestry
Wednesday, October 8, 1997
Mr. Chairman and other members of the Committee, my name is Dr. Michael Osterholm. I am the State Epidemiologist and Chief of the Acute Disease Epidemiology Section at the Minnesota Department of Health. I want to thank the Committee for this opportunity to present to you a perspective from the trenches regarding the modern world of foodborne diseases. Our group at the Minnesota Department of Health have been international leaders in describing the changing epidemiology of foodborne disease and the need for new tools in the public health arsenal to combat the ever growing and complex set of factors responsible for this problem. While I realize that today's hearing is aimed at controlling foodborne pathogens of meat, many of my comments will be germane to other areas of food safety.
First, let me share with you an interesting paradox which seems to exist with the safety of our nation's food supply today. Here is a copy of the Minneapolis Star Tribune newspaper from last Friday, October 3. On page 10 of that edition, there are two stories; one entitled "As Safety Concerns Rise, Clinton Gets Tough on Imported Produce" and right below that, "South Korea Suspends Its Imports of Nebraska Beef." Who is policing whom? This interesting position of these stories reflect both the common misunderstandings of the sources of foodborne disease and the factors responsible for its occurrence and at best, the piece meal and incomplete national and international approach to preventing it.
Foodborne disease is a critical public health problem today. In recent studies that our group has conducted looking at random segments of the population, we have found that previous estimates of foodborne disease in this country grossly underestimate the extent of the real problem. We believe that there are more than 250 million episodes of foodborne disease which occur in this country each year. Clearly, it is now the number one reason for visits to our nation's emergency rooms. Hopefully, we will have time for further discussion of this disturbing information later.
Let me take a step back for a moment to give you a sense of what it is that we can do today to reduce the risk of foodborne disease associated with meat. In the 19th century, milk from diseased cattle produced in unsanitary surroundings and distributed under filthy conditions to an increasingly urbanized population, sickened and killed consumers by the thousands. Wide acceptance of the germ theory and the sanitary awakening that followed, led to vast improvements in animal health and hygiene, and the safety of dairy products improved substantially. Dairy farmers in northern Europe discovered that heating milk fed to their calves further reduced the risk for tuberculosis in their herds and after overcoming concerns that the new thermal pasteurization technology would corrupt the dairy industry, destroy the nutritional value of milk, and lead to serious public health problems, the same level of protection was offered to human consumers a few decades later. This is what we now know today as pasteurized milk. However, for the safety of solid foods that enter our kitchens as raw agricultural commodities, including meat, poultry, seafood and fresh produce, we continue to rely solely on animal health programs and general sanitation. Therefore, as we approach the 21st century, preventing illness and death caused by bacterial and parasitic foodborne pathogens remain substantial public health problems.
Irradiation, or ionizing pasteurization as many of us would like to call it, of these same food items with low doses of gamma rays, x-rays or electrons, can and will effectively control bacterial and parasitic foodborne pathogens. Public concerns, similar to those raised against thermal pasteurization of milk, have been advanced in opposition to the use of this technology, and it has been claimed that if we paid more attention to sanitation and proper cooking, these products could be safely consumed without introducing new technologies.
Perhaps; however, the residual risk for infection that remains after state-of-the-art sanitation during production, harvest, processing, distribution, and preparation, still yields an unacceptable level of illness and death. In addition, the warning to properly cook works only if culturally acceptable food preferences do not include undercooked and raw foods. Recent outbreaks of foodborne illness associated with undercooked meat has stimulated interest in methods of pasteurizing solid food such as meat without altering its raw appearance and characteristics. Ionizing pasteurization is a well established process with clearly documented safety and efficacy that can be put into widespread use as quickly as facilities can be sited and built. Good practice guidelines and Hazard Analysis Critical Control Points programs (HACCP) can result in raw meat with sufficiently low levels of pathogen contamination that irradiation doses as low as 1-3 kGy yield adequate margins of safety for common foodborne pathogens such as Campylobacter, Cryptosporidium, Escherichia coli, Listeria, Salmonella and Toxoplasma. No other control for Campylobacter contamination of poultry meat is apparent and other approaches to ground beef safety have proven inadequate to prevent intermittent low-level contamination with agents such as E. coli O157:H7.
The food industry appears reluctant to fully embrace ionizing pasteurization despite the obvious and painful failure of alternative approaches to prevent foodborne infections. Much of this reluctance stems from the perception that consumers reject the process and refuse to buy irradiated food. Surveys have shown considerable consumer confusion and ignorance about food irradiation, and reports of public concern towards things radioactive are widespread. However, consumer surveys also show profound and growing public concern about microbial food safety, and decreasing concerns about the safety of irradiated food. Knowing as little about it as they appear to, approximately half of the consumers recently surveyed in one scientific study have expressed willingness to try irradiated food if it will decrease the risk for illness. In addition, when educated about food irradiation, 90% of survey participants expressed interest in purchasing irradiated food and when allowed to sample such food, interest increased to 99%. These survey results are summarized in a recent commentary authored by Dr. Morris Potter from the Centers for Disease Control and Prevention and me. It has been provided to the Committee. Let me summarize this part of my testimony by saying in the words of one of Senator Harkins' local heroes, "If you build it, they will come."
Ionizing pasteurization is not the cure for all food safety ills. Pasteurization of any sort is no match for bad sanitation and substandard practices. Ionizing pasteurization can be overwhelmed by large numbers of pathogens. Just as obvious, foods produced and processed under appropriate conditions that are then properly packaged and irradiated are subject to post-pasteurization contamination. In addition, the dose of irradiation used to pasteurize fresh meat and poultry are not sufficient to kill bacterial spores. Thus, if anaerobic packaging is the method used to protect irradiated foods from post-pasteurization contamination, Clostridium botulinum could pose a risk if the cold chain is disrupted.
Consumer surveys have demonstrated public concerns over worker and environmental safety that have also contributed to the reluctance of some to build and use food irradiation facilities. These concerns are appropriate and can be addressed. Because food irradiation and irradiation sterilization of nonfood items like medical supplies are so well established, proper facility design and operating characteristics are well known. The relatively short life of cobalt 60 and its insolubility in water reduces environmental concern. Food processed with ionizing radiation has no residual radiation nor does it create any unique radiolytic compounds. In plain English, irradiated meat is safe to eat! In addition, there is ample evidence to show that the use of irradiation does not cause any additional degradation of vitamins or other nutrient components of the food beyond that found for cooking, microwaving, or other methods of food preservation or treatment. This is why food irradiation has been approved by 40 countries and encouraged by the World Health Organization, the American Medical Association, and the Institute of Food Technologists. We cannot let the junk science so often voiced by those opposed to irradiation stand unchallenged any longer. The lives of our loved ones are at risk.
Thus, a broadly applicable solution to many of our food safety problems exists and has existed for decades. It is disappointing that the public health community has been silent for so long on this issue. This is particularly true for the President and the current administration given the President's obvious interest in food safety and the well documented problems with meat contamination of the past six months. Faced with the liability of marketing hazardous foods, it is puzzling why the food industry has not stepped into the vacuum created by this lack of leadership from public health. Our recent experience makes it clear that new foodborne hazards are being stacked on top of old, unresolved food safety problems--broadly applicable solutions are desperately needed. Just as thermal pasteurization of milk protected us from E. coli O157:H7 before we knew what was in raw milk, ionizing pasteurization can protect us from today's and tomorrow's emerging foodborne pathogens. Thank you.