Consumer acceptance and marketing of irradiated meat
Abstract:
Millions of dollars have been invested in food safety research to reduce foodborne illness caused by deadly bacteria. Despite research and huge investments, millions of consumers worldwide are still at risk. The CDC estimates that some 76 million Americans become sick from food-related illnesses each year, and approximately 325 000 of these are hospitalized. Approximately 5000 Americans die each year from foodborne diseases. Recalls of contaminated foods have resulted in huge economic losses, negative publicity and lawsuits. Existing technologies can reduce, but not eliminate, harmful bacteria in our food. Therefore, we need to look at all interventions that can reduce the risk of foodborne illness. Experts believe that food irradiation when used in combination with other technologies will increase the safety of our food. More than 40 countries have approved food irradiation and at least 30 are actually using the technology. Studies show that consumer acceptance of irradiated food increases significantly with education.
19.1 Introduction
Food safety is a cause of concern for consumers due to many highly publicized incidents of foodborne illness that occur despite multiple food safety interventions. Each year, millions worldwide become ill and thousands die from foodborne illnesses. The United States Department of Agriculture (USDA) estimates that diseases caused by the seven major foodborne pathogens result in medical costs and productivity losses between $6.6 and 37.1 billion annually (Grocery Manufacturers of America, 2009). Furthermore, massive recalls of contaminated food such as millions of pounds of ground beef and produce contaminated with Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes have resulted in severe economic losses to the affected industry.
The beef industry has invested millions of dollars in food safety research to reduce or eliminate the threat of foodborne illness from ground beef and beef products contaminated with deadly bacteria such as E. coli O157:H7 and Salmonella. Despite huge investments, there is still no silver bullet on the horizon to solve the problem.
After extensive research, multiple interventions including steam, sprays, washes and recently approved vaccines have proven to reduce, but not eliminate, pathogens in ground beef, mechanically tenderized steaks, and processed meats. Despite these commendable efforts, harmful pathogens still plague the industry and there is no sign that they can be further reduced, without additional intervention. Most experts agree that food irradiation is the most effective technology available to significantly reduce the risk of foodborne illness from contaminated meat and poultry as well as other products. In this chapter, we will describe the irradiation process, list current approvals, and provide an update about consumer acceptance and product introduction.
19.1.1 Background
Zero tolerance: in 1994, the US Food Safety and Inspection Service (FSIS) began routine testing of raw ground beef for E. coli O157:H7. The US Federal Meat Inspection Act of 1994 (USDA/FSIS, 2006) had defined the presence of E. coli O157:H7 in hamburger at detectable levels as an adulterant (USDA/FSIS, 2006) in response to a 1993 outbreak that resulted in 400 illnesses and four deaths (Marler Blog, 2007). Recalls of E. coli O157:H7 contaminated meat and related illnesses have continued to grow over the next decade. After 24 million pounds of contaminated beef were recalled in 34 separate incidences in 2002, recalls dropped to just over a million pounds a year for the next three years, and then to just 181,900 pounds in 2006 (Marler Blog, 2007). The US Centers for Disease Control (CDC) reported that E. coli O157:H7-related illnesses dropped 48% between 2000 and 2006 (Marler Blog, 2007), which was encouraging news for the meat industry.
19.1.2 Cause for concern
In April 2009, the CDC published the latest FoodNet data on the incidence of diseases caused by pathogens transmitted through food. Citing recent large, multi-state foodborne outbreaks as evidence, Dr Robert Tauxe, Deputy Director of CDC’s Division of Food-borne, Bacterial, and Mycotic Diseases, reported the progress in reducing foodborne illness in the US. Tauxe said, ‘We recognize that we have reached a plateau in the prevention of foodborne disease and there must be new efforts to develop and evaluate food safety practices from farm to table’ (CDC, 2008).
The CDC report should not be a surprise, since the latest data from USDA showed that E. coli contamination rates for ground beef have been on the rise since 2003 (USDA/FSIS, 2009). In 2008, 0.47% of ground beef samples tested positive for E. coli O157:H7, a number that is up from 0.24% of tested samples in 2007, 0.17% in 2006, and 0.16% in 2005. During the past two years, about 40 million pounds of beef have been recalled in at least 40 incidences due to E. coli O157:H7. During 2009, results from USDA/FSIS analysis of raw ground beef and raw ground beef component samples for E. coli O157:H7 showed 36 positive samples from 12 065 tested samples. This amounted to 0.30% down from 0.47% in 2008.
The US beef industry produces about 4 billion kilograms (85 billion pounds) of ground beef annually. This percentage of contamination corresponds to production of an estimated 18.5 million kilograms (40 million pounds) of E. coli O157:H7 contaminated ground beef each year. Based on these numbers, about four of every 1000 hamburger patties produced in the US may contain bacterial pathogens when they leave the manufacturing plant. If that contaminated ground beef is not properly cooked to 71 °C (160°F), it can cause serious injury or death. Furthermore, pathogens in the meat could potentially cross-contaminate other foods in the kitchen, if hands, utensils, and countertop spaces are not cleaned properly and kept sanitary.
The situation becomes more serious when we consider recent research by FDA/FSIS and others that shows that 75% of households own a meat thermometer, but only 6% of US consumers report using it often or always (Cates, 2002; International Food Information Council, 2009). Research at Utah State University confirmed these data (Anderson and others, 2004). The observational study showed that only five of 99 participants used a thermometer to determine doneness of meat, poultry, or seafood, and only six of those who owned a thermometer reported using it often/always. Nearly half of the study’s participants reported not knowing the recommended cooking temperature for ground beef (44%) or chicken (43%).
Recent widely publicized recalls have cost the food companies millions of dollars in lost sales. It is not unusual for a company to be forced out of business following a serious food safety incident, because of the cost of product recalls, resulting victim claims, litigation, and negative publicity. It is imperative that the food industry further enhances its efforts to provide the public with the protection they expect and deserve against foodborne illness.
19.1.3 Possible solutions
Pre-harvest and post-harvest interventions
Much has been written about best management practices from ‘farm-to-fork’ to reduce contamination. Since 1993, US beef producers alone have invested more than $27 million in beef safety research, while the overall cost to fight E. coli in beef since 1993 has exceeded $3 billion and is rising (Eustice and Bruhn, 2006). Interventions currently being used include on-farm sanitation, steam, hot water, and organic acids. These technologies can reduce bacteria by 2–3 logs (99–99.9%). Recent approval of E. coli vaccines show promise but further research is needed (Moss, 2009a). However, vaccines are costly and must be applied several times. Cattlemen must have a financial incentive to use them (Newman, 2009). Further, for maximum effectiveness, all beef used in ground meat should have come from vaccinated cattle, a difficult goal to attain.
Testing
Calls for increased product testing are everywhere. Even though increased testing may prevent the distribution of contaminated product in some cases, the International Commission on Microbiological Specification for Foods in 2002 (Book 7), concluded the following, ‘No feasible sampling plan can ensure complete absence of a pathogen. … It cannot be guaranteed that the lot of ground beef is completely free of the organism, no matter how large the number of sample units.’
19.2 Time to take a fresh look at irradiation
Despite efforts to reduce exposure to pathogens at every stage of beef production, harmful bacteria continue to be a cause for concern for the beef industry. One food safety alternative that has existed for many years in the food industry, and has been successfully used for almost a decade on a small portion of the ground beef industry, is irradiation.
19.2.1 Is irradiation the answer?
Irradiation inactivates E. coli O157:H7 and other microorganisms and parasites that cause foodborne illnesses. Some experts believe that irradiation will enhance the safety of meat, poultry, and produce, in a manner analogous to that of the improvement pasteurization had on the safety of milk 70 years ago. The major benefit of food irradiation is greatly reducing, and possibly even eliminating, the number of harmful organisms in a product. Other benefits include helping to keep meat, poultry, seafood and produce fresh longer, and helping to reduce the need for chemical fumigants used in some produce and grain to eliminate insects.
19.2.2 What is the food irradiation process?
There are several processes that are collectively referred to as ‘food irradiation’. The object of each process is to kill or impair the breeding capacity of unwanted living organisms or to affect the product morphology in a beneficial way that will extend product shelf-life. Each process has an optimal dose of ionizing energy (radiation) dependent on the desired effect. The dose of radiation is measured in grays (Gy). A ‘gray’ is a unit of energy equivalent to 1 joule per kilogram, and 1 kilogray (kGy) equals 1000 Gy. All three forms of ionizing energy (e-beam, gamma, and x-ray) have the same effect, gray for gray. All three forms of irradiation are referred to as a ‘cold process’. Although all of the radiation energy is converted to heat during treatment, the process typically increases the product temperature by only about 1 °C.
19.2.3 Why is food irradiated?
Food is irradiated to destroy bacteria, fungi, or parasites that cause human disease or cause food to spoil. Irradiation destroys harmful bacteria such as E. coli O157:H7, Salmonella, L. monocytogenes, Campylobacter, and Vibrio that are major contributors to the estimated 5000 deaths and 76 million cases of foodborne illnesses that occur every year in the United States. At the same time, parasites such as Cryptosporidium sp., Cyclospora sp., Toxoplasma gondii, and Trichinella are eliminated. When used in this manner, irradiation is comparable to pasteurizing milk, in that the product remains uncooked and fresh, but it is much safer after treatment. Irradiation also extends the shelf-life of food by retarding maturation in vegetables and reducing spoilage organisms that grow under refrigeration. Irradiated strawberries can last weeks in the refrigerator without developing mold compared to the non-irradiated control that normally has a refrigerated shelf-life of less than a week. Irradiation can also be used in place of fumigants and other quarantine procedures to allow fruits and vegetables to be imported or exported without risking the introduction of harmful insects to the receiving country (Food Irradiation Processing Alliance, 2006).
19.2.4 How is irradiation used?
Pasteurization (pathogen reduction)
Irradiation is used to effectively eliminate disease-causing organisms including bacteria and parasites (e.g., irradiating ground beef to significantly reduce the risk from E. coli O157:H7, or irradiating live oysters to reduce any Vibrio which could be present).
Sterilization
Irradiation is used at a very high dose (approximately 50 kGy) to eliminate all organisms including resistant bacterial spores so that refrigeration is not required (called commercially sterile or shelf stable). Examples include certain foods that are sterilized for NASA astronauts.
Sanitation
Irradiation at a dose of 5–10 kGy is widely used to reduce organisms in spices, herbs and other dried vegetable substances (e.g., irradiating spice blends that are added to meat for hot dogs and other ‘Ready-to-Eat’ products that may not be cooked again) prior to consumption.
Shelf-life extension
Shelf-life can be extended for certain foods using radiation at a dose of 0.052.5– kGy by lowering the population of spoilage-causing organisms, including bacteria and mold. 0n certain fruits and tubers, irradiation delays ripening and/or sprouting (e.g., irradiating berries reduces mold to extend their market reach. Irradiating potatoes, onions, and garlic impairs cell division and allows them to go through the ‘offseason without sprouting).
Disinfestation
Irradiation at a dose of 0.08–0.4 kGy is used to stop the reproduction of insect pests that potentially could be introduced into new regions of the world when insects or fertilized eggs ‘hitchhike’ on produce during shipment (e.g., irradiating foreign produced mangoes and other fruit from India, Mexico, Pakistan, Thailand and elsewhere to eliminate the seed weevil, which is a quarantined pest, for import to the US, or irradiating papaya to eliminate fruit flies, which are quarantined pests, for import from Hawaii or foreign countries into the US mainland). Note that the three types of irradiation, gamma, x-ray or electron beam produce the same effect. The critical parameter is penetration of the food with the appropriate dose.
19.2.5 What equipment is employed to irradiate food?
Food is irradiated in ‘irradiators’ that use electron beams or gamma rays or x-rays as their source of ionizing energy (radiation) (Food Irradiation Processing Alliance, 2006). All commercial irradiators have four primary components:
2. a method of product conveyance,
3. ‘shields’ to prevent exposure of personnel and the environment to radiation, and
Ionizing radiation is penetrating energy, and thus, products are usually irradiated after they are fully packaged. Below is a description of the four types of irradiators that are commercially available or in use today for food processing. The choice of which irradiator is most cost effective for a particular product depends on the type of product, how it is packaged, the product dose, dose uniformity requirements, and, most important, logistics.
Electron beam irradiator (employing a radiation chamber)
The source of electron beams is an ‘accelerator’. Accelerators generate and accelerate electrons very fast towards the food product being irradiated. Because electrons have mass, they can only penetrate about 1.5 inches (3.8 cm) into a typical food product or about 3.5 inches (8.9 cm), if the food product is irradiated on both sides simultaneously. Electrons also have an electric charge. This charge allows the stream of accelerated electrons to be scanned by magnets to track across the product. A commercial food electron beam irradiator accelerates the electrons to energies up to 10 million electron volts (10 MeV). Electron beam irradiators typically use massive concrete, steel or lead shielding. Electron beam accelerators can be turned on and off. Safety interlocks ensure that a person cannot enter the radiation chamber where the food is being irradiated when the accelerator is ‘on’. Product is usually passed through the scanned ‘beam’ on roller type conveyors.
Gamma irradiator (employing a radiation chamber)
The source of photons in a gamma irradiator is cobalt-60. Unlike electron beams that are generated on-site using electric power, cobalt-60 is produced off-site in nuclear reactors and transported in special shipping containers (‘casks’) to the site. Cobalt-60 is a solid radioactive metal that is contained in two welded encapsulations of stainless steel creating a ‘sealed source’. The sealed source contains the ‘radioactive’ cobalt-60, but allows the photons (‘radiation’) to pass through the encapsulation and into the food product. Because cobalt-60 photons have no mass, they can penetrate more than 24 inches (60 cm) into the food product, if irradiated on both sides. Gamma irradiators that employ a radiation chamber typically have shields made out of massive concrete or steel. Cobalt-60 continuously emits radiation and cannot be turned ‘off’. To allow personnel access to the chamber, the source is lowered into a storage pool of shielding water when it is not being used to irradiate product. The shielding water does not become radioactive. Safety interlocks are used to ensure that a person cannot enter the chamber when the source is not in the stored position (at the bottom of the pool of water). Hanging carriers, totes and roller conveyors are typically employed to move the product through the chamber.
Gamma irradiator (underwater)
Like the radiation chamber irradiator above, an underwater gamma irradiator uses cobalt-60. Unlike a radiation chamber, an underwater irradiator stores the cobalt-60 permanently at the bottom of a pool of water. Instead of raising the cobalt-60 into a shielded chamber, the product is placed in water-free containers, and the containers are lowered/raised using a hoist mechanism to/from the bottom of the pool adjacent to the cobalt-60 to receive a dose of radiation. The water acts as the shield. The shielding water does not become radioactive. No above ground shielding or radiation chamber is present. There is no need for interlocks to prevent personnel from entering a radiation chamber when the cobalt-60 is present, because there is no radiation chamber.
X-ray irradiator (employing a radiation chamber)
X-rays are photons and have similar properties to gamma rays emitted by cobalt-60. X-rays are generated by using an electron beam accelerator and converting the electron beam (up to 7.5 MeV) to photons by accelerating the electrons into a high density material such as tungsten, steel or tantalum. The sudden deceleration of the electrons generates x-rays and waste heat. This method of generating the radiation is very similar to an electron beam irradiator, including the ability to be turned on and off. The shielding and product conveyance are similar to that of a chamber type gamma irradiator. The safety interlocks are similar to both electron beam and chamber type gamma irradiators. The advantages of x-rays over electron beams are that they have good product penetration (over 24 inches, 60 cm, of food product, if irradiated on both sides). The advantage of x-rays over both types of gamma irradiators is that they do not require a shielding storage pool. However, there is substantial loss of energy during the conversion process. Thus, it suffers a severe cost disadvantage when compared to other types of irradiators for the same product volume throughput.
19.3 History of irradiation of foods
Food irradiation has been used for practical applications for more than a century (Iowa State University, 2010). Radiation occurs naturally from the sun and other components of our environment, such as gases and deposits of uranium ore in rock structures. Discoveries that led to our present understanding of the many types of radiation started more than a century ago. Early discoveries focused on the most important visible forms of radiation that we call ultraviolet and infrared radiation, the latter being especially effective in heating homes and foods. 0ther forms of radiation include X-rays, gamma rays, radio waves, microwaves, alternating current, and cosmic rays, all of which are part of what is called the electromagnetic spectrum (Waltar, 2004).
In the 1890 s, radioactive substances and x-rays were discovered (National Health Museum, 2010). The scientific revolution that occurred at the end of the 19th century opened up the previously unknown world of radiation. Within only three years, several major discoveries dramatically changed the scope of science, and, from then on, experimental investigations were no longer limited to the observable macroscopic world. They extended to the sub-microscopic world, which previously was not directly perceivable by human senses. In 1895, Wilhelm Conrad Roentgen in Würzburg, Germany discovered that cathode rays, which had puzzled physicists for decades because they produced electric discharges in low pressure gases, actually produced a mysterious secondary radiation with extraordinary properties, x-rays. In 1897, Joseph John Thompson demonstrated that cathode rays were electrons – extraordinary light particles charged with negative electricity (Chemical Heritage Foundation, 2010). Thompson, a British physicist, showed the cathode rays were composed of a previously unknown negatively charged particle, which was later named the electron. Today cathode ray tubes (CRTs) are used to create the image in a classic television set (Bellis, 2010). In the meantime, Henri Becquerel discovered a weak but spontaneous radiation emitted from uranium and was awarded the 1903 Nobel Prize for Physics.
The discovery of x-rays immediately had a tremendous impact on the scientific community and on the public. The first radiography, taken by Roentgen of his wife’s hand, was known throughout the scientific and medical communities within weeks, even though news was disseminated by ordinary mail (Waltar, 2004). Thompson’s discovery of uranic rays in 1897, did not appear to be as spectacular at first. Early in 1898, Marie Curie discovered that radiation is a property of the atom itself. The same year, she discovered with her husband Pierre Curie two new elements, polonium and radium, which spontaneously emitted millions of times more radiation than uranium, and she coined the term radioactivity (Waltar, 2004). From then on, Marie Curie’s main efforts in studying radioactivity was to make radium, and, more generally, to incorporate the new elements and forms of radiation into research tools, opening the way to dramatic breakthroughs in physics and chemistry, and later medicine through radiotherapy. In 1903, Marie and Pierre Curie shared the Nobel Prize for physics with Henri Becquerel.
19.3.1 Is irradiation used for non-food products?
The most significant use of irradiation has been in the medical field for medical and dental X-rays, in the detection and treatment of diseases, the sterilization of medical equipment, medical devices, pharmaceutical products, and home products; and the production of sterilized food for special hospital diets. It is also interesting to note that for many years precious stones have been irradiated to enhance color, as in diamonds, and also is used to turn clear topaz into blue topaz.
Irradiation is used to sterilize approximately 40% of the single use sterile medical devices currently manufactured in the US including: bandages, blood plasma, burn ointments, catheters, eye ointment, hypodermic syringes, orthopedic implants, intravenous administration sets, surgical drapes, sponges, swabs, surgeons’ gloves, procedure packs, trays, and sutures. Irradiation is also used for commercial products including microbial reduction or sterilization of: aerosol saline solutions, baby bottle nipples, baby powder, bulk cotton bales, contact lens cleaning solutions, cosmetic ingredients, bar and liquid soap, detergents, polishes, shampoos and hair cream. Food packaging that often is irradiated to eliminate bacteria include: bulk food containers, cream cups and lids, dairy and juice cartons, plastic roll stock, heat shrinkable film and laminated foil bags. Irradiation is also used on pet treats and various animal foods including special diets for laboratory test animals. Hundreds of other products are irradiated but not mentioned above (Food Irradiation Processing Alliance, 2006).
19.3.2 Irradiation of foods
Irradiation is a very effective way to treat a variety of problems in the food supply, including insect infestation of grains, sprouting of potatoes, rapid ripening of fruits and bacterial growth. More than 40 countries have approved food irradiation and more than 30 of these are actually using food irradiation technologies to ensure food safety and for disinfestation. Some of the countries utilizing food irradiation for various purposes include China, the United States, India, Mexico, Thailand, Vietnam, Indonesia, Australia, Russia, the Netherlands, South Africa, Ghana, Korea, Israel and France. It is estimated that over one billion pounds of food are irradiated worldwide annually (Food Irradiation Processing Alliance, 2006). In the US, irradiated foods have been used by astronauts, the military, and hospital patients for more than two decades. With the recent FDA approval of irradiation for controlling bacteria on red meats and green leafy vegetables, attention is again focused on expanding the uses and advantages of food irradiation. The United States is closer than it has ever been to seeing irradiation accepted for widespread use, due to recent outbreaks from E. coli O157:H7 and Salmonella in meat and produce.
Early in the 1900s French scientists discovered that irradiation could be used to preserve food. The first US and British patents were issued for use of ionizing radiation to kill bacteria in foods in 1905. Irradiation technology was not adopted in the US until World War II, when there was a need to feed millions of men and women in uniform. The US Army tested irradiation with fruits, vegetables, dairy products, fish and meats. Food irradiation gained significant momentum in 1947 when researchers found that meat and other foods could be sterilized by high energy and the process was seen to have potential to preserve food for military troops in the field. To establish the safety and effectiveness of the irradiation process, the US Army began a series of experiments with fruits, vegetables, dairy products, fish, and meats in the early 1950s (Molins, 2001).
In 1963 the FDA approved its use to control insects in wheat and wheat flour. In 1964, additional approval was given to inhibit the development of sprouts in white potatoes. In 1983, approval was granted to kill insects and control microorganisms in a specific list of herbs, spices and vegetable seasonings (the approved list of food products has subsequently increased). In 1985, the treatment of pork to control trichinosis was approved. In the same year, approval was granted to control insects and microorganisms in dry enzyme preparations used in fermentation-type processes. In 1986, approval was granted to control insects and inhibit growth and ripening in foods such as fruits, vegetables and grains. The first approval process to ‘pasteurize’ solid foods was granted in 1990 for the irradiation of packaged fresh or frozen uncooked poultry. This process reduces, but does not eliminate, bacteria, and the irradiated poultry is safer than unprocessed poultry, but still requires refrigeration.
Red meat was approved for irradiation in the US in December 1997. Maximum doses of 4.5 kGy were approved for uncooked, chilled red meat, and meat products, and doses of 7.0 kGy were approved for frozen red meat and products. These approvals are for the purpose of controlling microorganisms, including pathogens such as E. coli O157:H7. Just as with irradiated poultry, irradiated red meats still require post-process refrigeration or freezing. Higher doses that sterilize frozen and packaged meats were approved in 1995 for use only by NASA. The most recent approvals of irradiation in the US were for green leafy vegetables (spinach and lettuce) in 2008 and oysters in 2009.
19.3.3 How can we tell if food has been irradiated?
Irradiated foods destined for the retail store have a label or a sign indicating that they have been irradiated. This includes the internationally recognized symbol called the ‘radura’. Although you cannot tell by the taste or appearance, federal regulations require that irradiated foods be labeled and carry the ‘radura’ symbol (Fig. 19.1). Foods that contain irradiated ingredients or foods served in restaurants do not have to be identified as being irradiated.
19.3.4 How effective is irradiation?
Although irradiation cannot prevent primary contamination, it is the most effective tool available to significantly reduce or eliminate harmful bacteria in raw products and to make sure that contaminated meat and produce do not reach the marketplace. At doses that are commonly used, pathogens are reduced from up to 99–99.999%, depending on the pathogen strain, product characteristics, and actual dosage applied.
Food irradiation, therefore, has the potential to dramatically decrease the incidence of foodborne disease and has earned widespread support or approval from international and national medical, scientific, and public health organizations, as well as food processors and related industry groups. Dr Robert Tauxe of the CDC estimates that irradiating 50% of poultry, ground beef, pork, and processed meats in the US would result in a 25% reduction in the morbidity and mortality rate caused by foodborne pathogens in these foods. This measure was also estimated to prevent nearly 900 000 cases of infection, 8500 hospitalizations, more than 6000 catastrophic illnesses, and over 350 deaths each year (Tauxe, 2001). Given the probable number of unreported and undetected foodborne illnesses, this reduction is likely to be even greater (Table 19.1).
Table 19.1
Food irradiation: potential annual public health benefits by specific pathogen
Source: Tauxe (2001).
Dr Tauxe is currently updating his study but does not anticipate a significant change (Tauxe, 2009). The study does not include the cost and disability burden resulting from foodborne illness, hospitalization, and litigation. Despite widespread media attention from food recalls, serious illness, and death, food irradiation technology remains underutilized and sometimes misunderstood. An increasing number of leaders in the food industry are saying that the time has come for the food industry to take a serious look at irradiation.
19.3.5 Who endorses the use of food irradiation?
Many prominent medical organizations, researchers and government organizations, including the American Medical Association, the American Dietetic Association, and the CDC, endorse food irradiation. Other organizations endorsing the use of irradiated foods are included in Table 19.2 (Eustice and Bruhn, 2006).
Table 19.2
Food and public health organizations worldwide that endorse irradiation
| American Council on Science and Health | International Food Information Council |
| American Dietetic Association | The Mayo Clinic |
| American Farm Bureau Federation | Millers’ National Federation |
| American Feed Industry Association | National Cattlemen’s Beef Association |
| American Meat Institute | National Confectioners’ Association |
| American Medical Association | National Fisheries Institute |
| American Veterinary Medical Association | National Food Processors Association |
| Animal Health Institute | National Pork Producers Council |
| Apple Processors Association | National Meat Association |
| Centers for Disease Control & Prevention | National Turkey Federation |
| Chocolate Manufacturers Association | Northwest Horticulture Association |
| Codex Alimentarius | Produce Marketing Association |
| Council for Agricultural Science & Technology | Scientific Committee of the European Union |
| Florida Fruit and Vegetable Association | United Egg Association |
| Food and Drug Administration | United Egg Producers |
| Food Distributors International | United Fresh Fruit & Vegetable |
| Food and Agriculture 0rganization | Association |
| Grocery Manufacturers of America Health Physics Society | United Kingdom Institute of Food Science & Technology |
| Institute of Food Science & Technology | US Department of Agriculture |
| Institute of Food Technologists | Western Growers Association |
| International Atomic Energy Agency | World Health Organization |
19.4 Education: the key to consumer acceptance
Numerous consumer studies show that when given a choice and even a small amount of accurate information, consumers are not only willing to buy irradiated foods, but they also often prefer them over food treated by conventional means. A variety of market research studies conducted over the past two decades demonstrated that 80–90% of consumers will choose irradiated products over non-irradiated after they hear the facts and understand the benefits. According to a 1995–1996 study done by University of California at Davis, interest in buying irradiated foods among California and Indiana consumers increased from 57 to 82% after seeing a 10-minute video describing irradiation. A 1995 study at Kansas State University showed that more than 80% of 229 respondents would purchase irradiated instead of non-irradiated poultry, if both products were offered at the same price, and 30% were prepared to pay a 10% premium for irradiated chicken, and 15% indicated a willingness to pay a 20% premium. A 2003 study by Jefferson Davis Associates showed that 68% of 396 respondents in six Midwestern states were aware of irradiation, and 78% considered irradiated ground beef a ‘good thing’ (Fig. 19.2) (Jefferson Davis Associates, 2003).
Fig. 19.2 Overall appeal of irradiated beef concept (see text for results of the Jefferson Davis Study).
A 2001 study funded by the Cattlemen’s Beef Board showed growing consumer acceptance of irradiated ground beef (National Cattlemen’s Beef Association and the Cattlemen’s Beef Board, 2002). The study, which measured consumer perceptions about irradiated ground beef, revealed a sizeable potential market for the product. Researchers found that a person’s acceptance of irradiated beef was greatly influenced by initial perceptions. Four consumer segments were identified: strong buyers (27% of the test group), interested (34%), doubters (24%), and rejecters (15%) (Fig.19.3). The first three groups were identified as potential markets for irradiated ground beef, and the study suggested that by implementing consumer education programs and continuing product quality research, the market for irradiated ground beef should continue to grow. Nearly all the ‘strong buyers’ were ready to buy irradiated ground beef before the study, more likely to buy it after trying it, and willing to pay $0.10 more per pound for it. The ‘rejecter’ segment in the study rejected placebo ground beef patties and non-irradiated burgers that were intentionally mislabeled as ‘irradiated’ in the study as often as they rejected clearly marked irradiated patties. The study said that no amount of information would convince this group, which generally rejects any new product or technology.
Fig. 19.3 Consumer responses to irradiation before and after being provided with information (see text for references).
A 2002 study by Texas A & M University (TAMU) investigated Texas consumers’ knowledge and acceptance of food irradiation and the effects of information about food irradiation on consumer acceptance and willingness to pay for irradiated ground beef (Aiew et al., 2003).
Before the presentation of any information, about half of the respondents indicated a willingness to purchase irradiated ground beef. After receiving information about food irradiation, 89% of the respondents were willing purchasers. Even more (94%) indicated a willingness to buy irradiated ground beef after a second set of information on food irradiation was presented. The willingness-to-buy percentages in the TAMU study appears higher than estimates from the FoodNet Population Survey in 1998–1999 (Frezen et al., 2000). At least half of consumers indicated that they will buy irradiated food, if given a choice between irradiated and non-irradiated. 0thers have found that if consumers are first educated about irradiation, 60-80% or more will buy irradiated products (Bhumiratana et al., 2007; Martin and Albrecht, 2003; Pohlman et al., 1994).
Scientists at the University of Georgia surveyed 50 consumers in Atlanta over a 10-year period (1993–2003) to determine current consumer attitudes toward irradiation after consuming irradiated ready-to-eat poultry meat products and to evaluate differences in acceptance over that period (Johnson et al., 2004). The survey showed that more than twice as many consumers were willing to buy irradiated products in 2003 than in 1993 (69% versus 29%, respectively). The majority (66%) of the respondents were aware of irradiation; among these, 71% indicated that they were either ‘somewhat informed’ or ‘had heard about irradiation, but do not know much about it.’ Consumers in both studies expressed more concern for pesticide use and animal residues, food additives, bacteria, and naturally occurring toxins than they did for irradiation. Consumers expressed slight concern regarding irradiation; however, this concern had decreased significantly over the past 10 years. Approximately 76% preferred to buy irradiated pork and 68% preferred to buy irradiated poultry to decrease the probability of illness from Trichinella and Salmonella, respectively. The study also found that a fourth of all consumers would buy more beef, poultry, and pork, if these products were irradiated and labeled. This figure reflects a greater than 80% increase in the number of consumers who would buy more poultry and beef, respectively. Many respondents said they would pay a 1–5% premium for irradiated products, with a few more going as high as 6–10%.
The results of dozens of studies such as these at leading universities consistently indicate that information about the nature and benefits of irradiation is a major factor affecting consumers’ perception of and attitudes toward irradiated foods. These findings reflect the importance of informing the public about the hazards of foodborne pathogens and the potential benefits of irradiating foods. Studies consistently show that information plays an important role in consumer buying decisions, and consumers are generally receptive to irradiated foods when the benefits of irradiation are explained. Negative and erroneous information about the process can reduce demand for irradiated foods, but that negative information can be addressed openly and effectively (Fox, 2002).
A Food Science and Nutrition class at University of Wisconsin-Stout recently showed that accurate information significantly increases the percentage of students who view irradiation positively (Barnhart, 2009). Eighty-two undergraduate students were asked to rate their opinion of irradiated food on a 1 (lowest) to 5 (highest) point scale before and after a 40-minute lecture. Before the lecture, 25% of students rated irradiation in the 4 or 5 categories, 61% gave irradiation a neutral score of 3, and 12% gave a 1 or 2 rating. After the lecture, 96% of the students rated irradiation in the 4 and 5 categories, 4% were neutral, and 0% rated irradiation in the 1 or 2 categories.
During the past decade, the prevalence of irradiated foods entering commercial channels in the US has steadily increased. Although irradiated fruits, vegetables, and poultry have been available commercially on a limited basis since the early 1990s, the introduction of irradiated ground beef in Minnesota during May 2000 significantly increased awareness and interest in the technology. Estimates are that approximately 15–18 million pounds of irradiated ground beef and poultry were marketed in the United States during 2008 (Food Irradiation Processing Alliance, 2006). The volume of irradiated meat and poultry sold in the US has remained steady during recent years. Irradiated ground beef is available from several retail outlets, including Wegman’s Food Markets in the Northeast USA, Publix in the Southeast, and nationally through Schwan’s home delivery service, and Omaha Steaks by mail order and retail sales.
Wegman’s, Schwan’s, and Omaha Steaks have recently expanded their offerings of irradiated ground beef. Wegman’s Food Markets based in Rochester, NY, a 76-store East Coast supermarket chain, began offering irradiated fresh ground beef and ground beef patties in 2002. ‘We see the number of people who suffer from food related illness each year, and we need to do better for our customers,’ Daniel Wegman, the company’s chief executive officer, testified before a congressional subcommittee in 2008 (US House of Representatives, Energy and Commerce Committee, Subcommittee on Oversight and Investigations, 2008). Wegman’s offers 80% lean and 90% lean irradiated fresh ground beef year-round, and irradiated fresh ground beef patties during warmer months when consumers are more likely to be grilling. The beef comes from Nebraska and is irradiated at a Sadex Corporation plant in Sioux City, IA. The level of irradiation is such that it causes a reduction in E. coli O157:H7 equal to that achieved by cooking the meat to 160 °F. Wegman’s charges its customers about $0.30–0.40 more per pound for irradiated fresh ground beef, and irradiated products account for about 2% of the chain’s total ground beef sales.
Schwan’s began selling irradiated ground beef in 2000 and has three ground beef offerings, including their recently introduced irradiated breakfast steak. All Schwan’s raw ground beef is irradiated for safety. Omaha Steaks irradiates all of their raw ground beef, and ground beef sales have doubled since they began using irradiation and marketing their products by mail order and in 85 retail stores in 22 states (Weiss, 2009).
19.4.1 Mango momentum
Currently there is much interest in irradiation for use in produce. Highly publicized recalls of spinach, lettuce, tomatoes, jalapeño peppers, sprouts and even peanut paste have caused produce growers and marketers to seek permanent solutions. Research shows that irradiation is very effective at reducing bacteria in many produce items such as spinach and iceberg lettuce without compromising quality. US Food and Drug Administration regulations have only approved iceberg lettuce, limiting use of this process by the leafy green industry. When additional greens are permitted, use of irradiation to enhance leafy green safety may increase. Irradiation prevents foreign fruit flies from damaging domestic produce, and allows consumers to enjoy items like imported mango, mangosteen and papaya. Estimates are that some 14 million metric tons (30 million pounds) of irradiated fruits and vegetables, mainly mango, mangosteen, papaya and guava, are sold annually by US retailers. Hawaii Pride based in Keeau, Hawaii exports more than 9 million pounds of irradiated produce annually including papayas, rambutan, star fruit, purple sweet potatoes, lychees and bananas annually to major supermarkets on the US mainland. USDA/APHIS reciprocal agreements have been signed by India, Mexico, Thailand, Vietnam, Laos, South Africa, Pakistan, Philippines and Malaysia that allow the importation into the US of produce from cooperating countries that was previously prohibited due to the risk of importing pests along with the produce. Mangoes from India have been available at selected stores in the US since 2007. Irradiated mangosteen from Thailand and dragon fruit from Vietnam are also starting to appear at Asian specialty stores nationwide. In early 2009, Mexico began to export irradiated guavas and mangoes to the US. Pakistan began to export mangoes to the US in 2010 as a result of irradiation. The availability of irradiated produce will increase dramatically in the future because of food safety concerns involving leafy green vegetables such as spinach and lettuce and an expanding market for exotic produce from Asian countries. All foods that have been irradiated must be labeled as such and carry the ‘radura’ symbol at retail.
19.5 Future trends
Food preservation methods have evolved from the earliest days of sun drying to salting, smoking, pickling, fermentations, canning, heating, freezing, and the addition of chemicals such as methyl bromide. Today, food irradiation is positioned to become a leading 21st century alternative for ensuring food safety. With world population expected to reach over 9 billion by 2050, it is crucial that foods are preserved and protected against contamination until consumed. Infestation and spoilage prevents at least one-quarter of the world’s annual food production from reaching the mouths of its populace. The percentage of harvested seafood that never reaches a human mouth is even higher – sometimes over 50%, particularly in countries with warm and humid climates that are characteristic of many developing nations. In addition to spoilage of massive quantities of needed nourishment, food can become unsafe for consumption through contamination by bacteria, parasites, viruses, and insects. Efforts to reduce world hunger and prevent a global food crisis need to take a multi-pronged approach. We must expand the Green Revolution to regions of the world most affected by famine such as sub-Saharan Africa; we must improve the distribution infrastructure in developing countries; and we must use food irradiation on a routine basis. Food irradiation will protect public health by reducing or eliminating harmful bacteria in meat, poultry and produce and irradiation will save food by slowing the spoilage process by extending the shelf-life of fruits and vegetables.
Irradiation will protect public health by eliminating harmful bacteria, while also allowing access to new markets by destroying unwanted pests. There is a growing need to use irradiation as a tool to prevent food spoilage by extending shelf-life of produce and other foods. When spoiled food is thrown in the garbage, the cost is much more than the price of the food. The cost of producing the food and transporting it to market should also be included. The cost also includes the price of land to grow the crop; seed, fertilizer, labor and petroleum to plant the crop; water to irrigate the land, harvesting costs and the cost of transportation to market. With 30–50% of the food produced being wasted, the time has come to find real solutions to a very real problem.
The CDC estimates that some 76 million US citizens become sick from food-related illnesses each year, and approximately 325 000 of these persons are hospitalized. Approximately five thousand Americans die each year from foodborne diseases, beginning with symptoms including nausea, cramps, and diarrhea (Tauxe, 2001). For the most part, these deaths occur one by one – with little public attention, but there have been several instances in the past decade or so that have led to public outcries. One such event occurred in 1993 when hundreds of people were stricken by E. coli O157:H7 and four children died after eating undercooked hamburgers at fast-food restaurants in the Western United States (Marler Blog, 2005–2010). Subsequent outbreaks have led to huge recalls of produce and meat and poultry products. A large recall in the United States occurred in 1997 when Hudson Foods ordered 25 million pounds of hamburger patties to be destroyed (CNN Interactive, 1997). In October of 2002, Pilgrim’s Pride Corporation recalled 27 million pounds of turkey and chicken products after 40 people became very ill and 8 died from listeriosis poisoning in the Northeast (Injury Board.com, 2002). Stephanie Smith, a 22-year-old dance instructor from Minnesota was stricken with hemolytic uremic syndrome after eating an undercooked hamburger contaminated with E. coli O157:H7 in 2007 (Moss, 2009b). She first noticed stomach cramps, which were tolerable on the first day, but soon turned to bloody diarrhea followed by convulsions. Doctors at the Mayo Clinic put her in an induced coma for nine weeks. When she emerged, the affliction had ravaged her nervous system and left her paralyzed. A $100 million lawsuit was filed against the manufacturer of the hamburger (McKinney, 2009). Had this food been irradiated, these people would not have become ill, let alone died.
19.6 Conclusion
No one single intervention can provide 100% assurance of the safety of a food product. All interventions that can reduce the risk of foodborne illness in the context of a farm-to-table, prevention-oriented approach to minimizing harmful contamination should be considered. That is why meat and poultry processing plants use a multiple barrier (hurdle) approach utilizing several types of interventions such as thermal processes combined with chemical and antimicrobial treatment to achieve pathogen reduction. These technologies have successfully reduced, but not eliminated, the amount of harmful bacteria in ground beef. While there are no silver bullets, irradiation can significantly improve food safety. Food irradiation does not eliminate the need for established safe food-handling and cooking practices, but when used in combination with other technologies including an effective Hazard Analysis Critical Control Points (HACCP) program, irradiation becomes a highly effective and viable sanitary and phytosanitary treatment for food and agricultural products. Irradiation is one of the most effective interventions available because it significantly reduces the dangers of primary and cross-contamination without compromising nutritional or sensory attributes.
The USDA’s FSIS, which oversees the irradiation of raw meat and poultry, cautions that the process is not a substitute for good sanitation and safe food handling. Establishments that use irradiation must meet the same sanitation and processing standards required of all meat and poultry plants. And while irradiation reduces pathogens, it is not necessarily intended to make the meat or poultry sterile. ‘The process does not replace proper cooking or food handling practices by producers, retailers, and consumers,’ according to a USDA publication (USDA Food and Nutrition Service, 2003). Research and actual experience show that informed consumers may readily accept, and may even prefer the product. Those companies that have been marketing irradiated meat and produce for several years know that there’s minimal consumer resistance. For the vast majority of consumers, the use of irradiation is a non-issue. During the 20th century, life expectancy in the US increased from 47 to 77 years (National Center for Health Statistics, 2004). Many public health experts attribute this dramatic increase to the 3 ‘pillars’ of public health; pasteurization, immunization and chlorination. Many of these same experts predict that food irradiation could become a 4th Pillar of Public Health. 0nly time will tell, whether this prediction lasts, as we strive in this modern age of unparalleled scientific and technical advances to make foods wholesome, nutritious, and safe in the US, and possibly to the hungry across the world.
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