Emerging Microbiological Food Safety Issues . . . and Solutions
Food Insight
March/April 2002
Americans have come to depend on (and expect) a relatively safe food supply, and that's what we've had for many years now. In fact, because our food is usually so safe, we often take it for granted. Safe food doesn't just happen, however; it takes the efforts of many individuals, organizations, industries, and the government to keep the U.S. food supply safe.
Technology has also played a vital role in making our food safe. Where would we be without refrigeration, pasteurization, and commercial canning methods, for example? Yes, the United States does have one of the safest food supplies in the world, but we can't rest on our laurels. For, despite our progress, there is one area of food safety that will probably always need attention: food-borne illness.
More than 200 known diseases are transmitted through food. According to the Centers for Disease Control and Prevention (CDC), there are millions of cases of food-borne illness each year, with approximately 5,000 deaths. Although experts admit that the U.S. food supply will never be 100 percent safe in every respect, continuing research on and development of preventive measures are clearly necessary for the health of the public.
A New Food Safety Frontier
The Institute of Food Technologists (IFT) released an expert report, Emerging Microbiological Food Safety Issues, in February 2002 that addresses the safety status of the U.S. food supply and makes recommendations for the most effective ways to decrease food safety risks. The comprehensive report, a product of a panel of experts in the areas of food-borne illness and food safety management, discusses specific food-handling procedures that can significantly reduce the risk of illness at each step of a food's journey to the table. It also points out issues that are expected to have an increasing impact on food safety: the globalization of the food supply and the continued development of food technology will be primary influences in the future.
What can be done to keep our food safe? "To achieve our public health goals, everyone along the farm-to-table continuum must take responsibility for their role in food safety management," says Mary Helen Arthur, science information manager at IFT and lead editor of the report. "A flexible, science-based approach that relies on all parties to fulfill their roles is our best strategy against emerging microbiological food safety issues," adds Arthur. For consumers—who bear the bulk of responsibility for food safety—this means becoming more aware of their food-handling behaviors and modifying those behaviors such as separating raw and ready-to-eat foods and paying attention to proper refrigeration in order to decrease the risk of food-borne illness. For health educators and communicators, this means increasing their efforts to get information to consumers.
For the food industry, proactive partnering with regulatory agencies and sharing of scientific information will be important in forming appropriate food safety policies in the future. In addition, a commitment to the development and utilization of new ingredients and techniques will also be key to maintaining a safe food supply.
Over the years the innovative use of food ingredients has enhanced the safety of food. Because of the effectiveness of these ingredients and their potential benefit to food safety, they are now widely used throughout the food industry. One such ingredient is sodium lactate, which was used as an antibotulism ingredient starting in the 1980s and which is now commonly used throughout the meat industry. Today, sodium lactate is once again in the food safety spotlight, however, as researchers have recently found it to be useful in fighting the food-borne pathogen Listeria monocytogenes.
Sodium and Potassium Lactate and Sodium Diacetate
L. monocytogenes is a type of bacterium that is usually found in soil, water, unpasteurized dairy products, and vegetables. Foods made from meat, poultry, and seafood can also be contaminated with Listeria; and ready-to-eat foods such as hotdogs and lunchmeat can become contaminated with the organism even after processing.
For most people, consumption of a food contaminated with Listeria is not a problem. However, for pregnant women, newborn babies, older adults, and people with weakened immune systems, they can become infected and develop listeriosis, which can be very dangerous.
Over the past several years reducing and eliminating Listeria has been a key area of research in the meat industry. Many years ago the U.S. Department of Agriculture (USDA) approved the use of sodium or potassium lactate or sodium diacetate separately in meat products to improve flavor, color, and quality. Recently, however, food technologists have discovered that the potential for L. monocytogenes growth could be reduced in ready-to-eat cured meats if products were formulated to contain a combination of lactate salts (sodium and potassium lactate) and sodium diacetate.
Scientists have long known that lactates can inhibit the growth of microorganisms. After much research and testing they found that putting the two—lactate and diacetate —together was more effective than using either one alone. "The combination of lactate and diacetate has become an effective weapon for fighting the long-standing nemesis of the food industry, Listeria monocytogenes," says Michael P. Doyle, Ph.D., professor and director of the Center for Food Safety, University of Georgia. It is being widely adopted by the processed meat industry.
Activated Lactoferrin
Listeria isn't the only bacterium that food scientists are working hard to eliminate: Salmonella, Escherichia coli, Campylobacter, and Staphylococcus can all cause illness if they are consumed in foods. One new food ingredient—activated lactoferrin—has shown great promise in inhibiting the growth of these and other bacteria on raw meats.
Lactoferrin is a naturally occurring milk protein obtained from whey (a by-product of cheese manufacturing). By applying a form of lactoferrin to the surfaces of meats, many types of harmful bacteria become unable to attach to the meat and therefore don't multiply or grow. The U.S. Food and Drug Administration has already classified activated lactoferrin as a generally recognized as safe (also known as GRAS) food ingredient, and the USDA is now reviewing it.
Interestingly, it doesn't take much lactoferrin to do the job. The amount required to eliminate harmful bacteria on a serving of meat is less than the amount found in a single glass of milk. In addition, individuals who are lactose intolerant can safely consume products that have been treated with activated lactoferrin because it is a protein. People who are lactose intolerant have difficulty digesting the sugar (lactose) found in milk. Food labels will most likely indicate the presence of milk-derived lactoferrin so consumers will be aware of its presence.
Other Ways to Make Food Safe
Achieving a safe food supply is a complicated task that requires a variety of approaches. For example, in addition to the new ingredients described above, research and development on state-of-the-art sanitation programs, improved quality control procedures, improved means of food storage and transportation, and even improved agricultural practices are under way around the country.
Food irradiation is another method of reducing the number of harmful bacteria in food. In 1963 irradiation of foods was approved for use in the United States. Since then various fruits, vegetables, grain products, and meats have been irradiated for safety. Irradiation is not a sterilization process in that it doesn't kill all food-borne pathogens, but it does destroy many of them, making it another useful tool in food safety.
Consumer food safety education programs of various governmental agencies and other organizations have also been around for a long time. These programs serve an important public health function in making it known that proper cooking and handling of food by the consumer are vitally important to keeping food safe.
It's a Team Effort
In the United States we are fortunate to have a strong food safety system that has been in place for many years. This system is constantly evaluated and improved to take advantage of advanced research, new technologies, and state-of-the-art equipment. According to the IFT report, "Combinations of food manufacturers' efforts, regulatory programs, and consumer actions have driven down rates of certain food-borne disease, but continued efforts are necessary." Clearly, keeping our food safe requires a "team" approach—and on this team, every player's contribution is important.
