Advanced Decontamination Technologies Irradiation

Meat Preserving And Curing Guide

A Cured Meat Guide for Everyone

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Eun Joo Lee and Dong U. Ahn


Bacterial food-borne illnesses account for an estimated 76 million cases, 325,000 hospitalizations, and 5,000 deaths each year in the United States (CDCP, 2005), and 5,300 food-borne outbreaks in Europe resulted in 5,330 hospitalizations and 24 deaths in 2005 (Aymerich, Picouet, & Monfort, 2008). Major food-borne pathogens of concern include Escherichia coli O157:H7, Campylobacter jejuni/coli, Salmonella spp., Listeria monocytogenes, Clostridium botulinum/perfringens, Staphylococcus aureus, Aeromonas hydrophylia, and Bacillus cereu, and spoilage microorganisms include Pseudomonas, Acinetobac-ter/Moraxella, Aeromonas, Alteromonas putrefaciens, Lactobacillus, and Bro-chothrix thermosphecta (Mead et al., 1999).

Meat is one of the major foods that cause food-borne illness in human and thus meat sanitation systems are required to use various intervention strategies to reduce or eliminate bacteria. Preharvest reduction of microorganisms in livestock and postharvest decontamination of carcass and meat are common intervention strategies for pathogens in meat (Ahn, Lee, & Mendonca, 2006). Intensifying the immune system of live animals by dietary supplementation of known immune stimulants is commonly used as a preharvest intervention. Postharvest intervention methods of meat use various chemical and physical treatments, which include carcass decontamination, antimicrobial additives, and irradiation.

Irradiation is among the most effective postharvest intervention methods for inactivating food-borne pathogens in meat. Exposing meat products under ionizing radiation such as gamma rays or high-energy electrons can kill pathogens as well as indigenous microflora, and extend shelf life. The major advantages of irradiating foods include (1) potentially toxic chemicals can be avoided and (2) products can be treated after final packaging, and thus, further cross

Animal Science Department, Iowa State University, Ames, IA 50011, USA e-mail: [email protected]

F. Toldra (ed.), Safety of Meat and Processed Meat,

Food Microbiology and Food Safety, DOI 10.1007/978-0-387-89026-5_8,

© Springer Science+Business Media, LLC 2009

contamination during postprocessing handling is prevented. The toxicological and microbiological evaluations of irradiation as well as wholesomeness for irradiated foods have been studied for over 60 years (WHO, 1994), and no other food technology has such a long history of scientific research before gaining approval (AMA, 1993).

Food Irradiation

Since Willhelm von Roentgen discovered X-rays in 1895, the use of ionizing radiation to preserve foods by destroying spoilage microorganisms was proposed (Minsch, 1896; Brynjolfsson, 1989) and X-rays were applied to kill Trichina in pork in 1921 (Schwartz, 1921). However, food irradiation was economically unfeasible in the United States until World War II because of the high cost of ionizing radiation sources (Urbain, 1989). The Department of the Army, the Atomic Energy Commission, and private industry sponsored the exploratory food irradiation research in the United States from 1940 to 1953 (Thayer, Lachica, Huhtanen, & Wierbicki, 1986). Since the US Army Medical Department began to assess the safety of irradiated foods in 1955 (CAST, 1986), petitions for the approval of irradiation of specific foods to the Food and Drug Administration (FDA) were followed and commercial radiation equipments and sources were developed. The food irradiation facility for the Army's research laboratories was built in Natick, Massachusetts, in 1962 and the Army conducted scientific food irradiation researches using bacon, ham, pork, beef, hamburger, corned beef, pork sausage, codfish cakes, and shrimp. In 1963, wheat and wheat powder were the first products approved by the FDA (Mason, 1992; Federal Register, 1999). The National Aeronautics and Space Administration (NASA), a pioneer in the use of irradiated food, first used irradiated meats in 1972 for astronauts to consume in space and then irradiated ham, turkey, beef steak, and corned beef were used in the Apollo-Soyuz Test Project (ASTP) where irradiated foods were shared with the Russian cosmonauts in 1975 (Karel, 1989).

In 1980, the Food and Agriculture Organization of the United Nations, the International Atomic Energy Agency, and the World Health Organization (FAO/IAEA/WHO) stated that ''irradiation of any food commodity up to an overall average dose of 1 Mrad (10 kGy) presents no toxicological hazard and introduces no special nutritional or microbiological changes; hence toxicologi-cal testing of foods so treated is no longer required'' (WHO, 1981). During 1980s, the FDA approved petitions for irradiation of spices and seasonings, fresh fruits, and dry substances and the USDA-approved pork (USDA-FSIS, 1986), poultry (USDA-FSIS, 1992), and red meats (USDA-FSIS, 1999). The use of irradiation in meat is restricted to raw, packaged poultry at 1.5-3.0 kGy, and fresh and frozen red meat at a maximum dose up to 4.5 and 7.0 kGy, respectively (Sommers, 2004). The maximum irradiation doses approved for

Table 8.1 Maximum irradiation dose








Wheat flour


Control molds


Fresh fruit and vegetables


Inhibit sprouting, delay ripening, disinfestation of insects


Dehydrated spices and herbs


Control pathogens


Poultry meat


Control pathogens


Refrigerated meat


Control pathogens

Frozen meat


Control pathogens

Dehydrated enzymes


Control pathogens


Shell eggs


Control of Salmonella


Molluscan shellfish


Control of Vibrio bacteria and other food-borne microorganisms

food products in the United States are listed in Table 8.1. Currently, 56 countries have permitted irradiation of food, and more than half a million tons of food are irradiated annually in the world (Loaharanu, 1994; NAPPO, 1995; IAEA, 1999)

Principles of Irradiation

Atoms are consisted of protons, neutrons, and electrons, which are held together by energy (Thakur & Singh, 1994). When these nuclear particles lose balance by changing the arrangement of forces, this unstable atom can restabi-lize by emitting energy to rebalance the nucleus. This emission of energy, as particles or waves, is termed "radiation" (Halliwell & Gutteridge, 1989). If radiation has sufficient energy to move atoms in another material without chemical changes it is called as a "non-ionizing radiation", and if it also has sufficient energy to break chemical bonds it is called as "ionizing radiation'' (Josephson & Peterson, 2000). High-energy sources such as accelerated electrons, gamma rays, and X-rays are ionizing radiations because those can create ions or free radicals from atoms (CAST, 1989).

Gamma rays are emitted as a photon from nucleus and X-rays from electron fields when the energy of atoms is exhausted (Lagunas-Solar, 1995). Gamma rays do not ionize atoms directly; when a photon or an accelerated electron enters a material, the electron of an atom in that material increases in energy level and leaves its orbit. The ejected electron, called "Compton electron'', transfers its energy to a secondary electron and cause further excitation and ionization in the material (Diehl, 1995). Until Compton electron's energy is not enough to cause electrons to leave their orbital, energy is passed through a cascade of electrons (Venugopal, Doke, & Thomas, 1999). The quantity of energy absorbed by something (food) as it passes through a radiation field is called "radiation absorbed dose''. The unit of irradiation dose is expressed as Gray (Gy), which is equal to the absorption of energy equivalent to one Joule per kilogram of absorbing material (1 Gy = 1 J kG 1 = 6,200 billion MeV absorbed/kg of food = 0.01 calorie/lb of food = 100 rad, 1 rad = 100 erg/g) (Dragnic & Dragnic, 1963).

As irradiation energy applied to biological materials ejects electrons from the atoms or molecules of the materials and produces ions and free radicals (Woods & Pikaev, 1994), the cellular components such as DNA, pigments, fatty acids, and membrane lipids can be damaged (Olson, 1998a). The first target of highly energized electrons is water molecule in biological materials and hydroxyl radical (HO*), a powerful oxidizing agent, is formed (Taub, Karielian, & Halli-day, 1978; Taub et al., 1979). The dispersion of free radicals is higher in liquid form than in limited free water form (dried products) or the crystalline form (frozen products) (Thakur & Singh, 1994). When the DNA of living cells is exposed to hydroxyl radicals, both single and double strands in the molecule are broken and large molecules have a greater probability of being affected than smaller molecules because dispersion of electrons are purely random. Therefore, human have a greater damage than microorganism when they are exposed to radiation energy and higher dose of radiation energy is required to kill microorganism than bigger size animals (Thayer, 1995).

Currently, both e-beam and gamma rays are used as radiation sources for commercial food irradiation. 60Co is the most common energy source that produces gamma rays and commonly used to treat food contained inside a package because it is highly penetrable (Venugopal et al., 1999). Electron beam is a stream of high-energy electrons that are propelled out of an electron gun (Josephson & Peterson, 2000). Electron beam accelerators accelerate electrons to a beam (up to 10 MeV) with single-sided treatment and 10 MeV electrons can give satisfactory treatment for thicknesses up to about 35 mm of unit density material. Using a conveyor belt with double-sided, a product thickness of 8 cm can be used (Satin, 2002). Although electrons are less penetrable than gamma rays, electron beam can be useful for large volumes of free flowing food items such as grains or packages offish fillets with no more than 8-10 cm thickness (Jarrett, 1982). Although X-rays have relatively high penetrating power, they are rarely used in food irradiation due to poor conversion of accelerated electrons to X-rays (Hayashi, 1991).

Microcidal Effect of Irradiation

Several factors such as irradiation dose, meat composition, temperature, gaseous atmosphere, and microbial factors influence to kill microorganisms in meats by irradiation (Olson, 1998b). High doses of radiation are needed to destroy larger populations of food-borne microorganism, but it negatively impacts the organoleptic qualities of meat. High amount of proteins and natural antioxidants such as carnosine and vitamin E in meat decrease the antimicrobial efficacy of ionizing radiation because they neutralize free radicals (Diehl, 1995; Steccheni et al., 1998). Irradiation of sweeteners such as dextrose produces peroxides, which theoretically should further contribute to microbial inactivation during irradiation of dextrose-containing RTE meats (Kawakishi, Okumura, & Namki, 1971). Free fatty acids, carbonyl compounds, hydrogen peroxide, and hydroperoxides produced from irradiated fats increase the killing effect of irradiation in foods (Diehl, 1995).

Freezing meat reduces water activity by converting water to ice. The reduced water activity increases irradiation resistance of microorganisms because the generation of free radicals from water is drastically reduced (Diehl, 1995) and the migration of free radicals to other parts of the frozen product is impeded (Taub et al., 1979). Most published research indicated that the presence of oxygen increased the killing effect of irradiation in meat (Hastings, Holzapfel, & Niemand, 1986; Patterson, 1988; Fu, Sebranek, & Murano, 1995; Thayer & Boyd, 1999).

Microbial factors such as numbers, types, and physiological status of microorganisms in meat can affect the extent of microbial destruction by irradiation. For example, viruses have much higher radiation resistance than bacterial

Table 8.2 D-values of food-borne pathogens and spoilage bacteria


D10 (kGy)



A. hydrophila



Palumbo et al. (1986)

B. Cereus (vegetative)



Grant et al. (1993)

C. jejuni



Clavero et al. (1994)

C. perfringens


Farkas (2006)

E. coli O157:H7(incl.




Clavero et al. (1994)

Lactobacillus spp.


Farkas (2006)

L. monocytogenes



Huhtanen et al. (1989)



Grant and Patterson (1991)



Monk et al. (1994)

Salmonella spp.



Thayer et al. (1991)

Staphylococcus aureus



Thayer and Boyd (1992)


Roast beef

Patterson (1988)

Y. enterocolitica



El-Zawahry and

Rowley (1979)

Cl. botulinum (spore)



Anellis et al. (1977)

C. sporogenes (spore)


Beef fat

Shamsuzzaman and Lucht


M. phenylpyruvica



Patterson (1988)

P. putida



Patterson (1988)

S. faecalis



Patterson (1988)

spores, which in turn show a higher radiation resistance than bacterial vegetative cells. Bacterial vegetative cells are more radiation resistant than fungi (yeast and molds). Gram-negative bacteria are generally more sensitive to ionizing radiation than Gram-positive bacteria (Ehioba et al., 1988; Lambert, Smith, & Dodds, 1992; Thayer, Boyd, & Jenkins, 1993). Non-spore forming bacteria exhibit a greater sensitivity to irradiation than spore formers. The radiation response of microbial populations is expressed by the decimal reduction dose (D10-value), and the D10-values of food-borne pathogens and spoilage bacteria are listed in Table 8.2

Effects of Irradiation on Meat Quality

The application of irradiation technology in meat industry is limited because of quality and health concerns about irradiated meat products. Irradiation produces a characteristic aroma and color that significantly impact upon consumer acceptance. Consumers associate the brown/gray color in raw beef with old or low-quality meat, red/pink color in irradiated cooked light meat with under-cooked or contaminated, and off-odor and off-flavor with undesirable chemical reactions. Thus, developing methods that can prevent these quality changes in meat by irradiation is important for implementing irradiation technology by the meat industry.

Ionizing radiation generates hydroxyl radicals, the most reactive oxygen species in nature, by splitting water molecules (Thakur & Singh, 1994). Thus, irradiation can increase lipid oxidation in meat significantly because meat contains 75% or more of water. The presence of oxygen also has a significant effect on the development of lipid oxidation and odor production (Merritt, Angelini, Wierbicki, & Shuts, 1975). Therefore, excluding oxygen from meat products, whether they are irradiated or not, is very important to stop oxidative chain reactions (Ahn, Wolfe, Sim, & Kim, 1992). Ahn et al. (1998) reported that preventing oxygen exposure after cooking was more important for cooked meat quality than packaging, irradiation, or storage conditions of raw meat. Diehl (1999) indicated that irradiation of aqueous systems produced hydrogen peroxide, particularly in the presence of oxygen. During postirradiation storage, hydrogen peroxide gradually disappears while other constituents of the system are oxidized. Lee and Ahn (2003) reported that TBARS values of oil emulsion samples immediately after irradiation were lower than those of nonirradiated samples. After 10 days of storage, however, irradiated samples developed higher TBARS values than nonirradiated emulsions. Especially arachidonic acid, linolenic acid, and fish oil, which had a high proportion of polyunsatu-rated fatty acids, had accelerated lipid oxidation after irradiation. Nawar (1986) reported that a series of dienes, trienes, and tetraenes were formed from unsaturated triacylglycerols by irradiation at 60 kGy under vacuum conditions. The radiation chemistry of refrigerated and frozen meat could be different because free radicals with less mobility in the frozen state tend to recombine to form the original substances rather than diffuse through the food and react with other food components (Taub et al., 1979). Therefore, oxidative changes in irradiated frozen products are slower than that of the refrigerated products.

Irradiation greatly increased or newly produced many volatile compounds such as 2-methyl butanal, 3-methyl butanal, 1-hexene, 1-heptene, 1-octene, 1-nonene, hydrogen sulfide, sulfur dioxide, mercaptomethane, dimethyl sulfide, methyl thioacetate, dimethyl disulfide, and trimethyl sulfide from meat (Ahn, Jo, & Olson, 2000; Fan, Sommers, Thayer, & Lehotay, 2002). Early investigators assumed that the off-odor was the result of lipid oxidation, which was initiated by the irradiation process. They postulated that carbonyls were formed in irradiated meats after the reactions of hydrocarbon radicals, the major radiolytic products in fat, with molecular oxygen (Champaign & Nawar, 1969; Merritt, Angelini, & Graham, 1978) and it caused the off-odor of irradiated meat with following the same pathway as normal lipid oxidation. Aldehydes contributed the most to oxidation flavor and rancidity in cooked meat and hexanal was the major volatile aldehyde (Shahidi & Pegg, 1994). When triglycerides or fatty acids are irradiated, hydrocarbons are formed by cutting CO2 and CH3COOH off from fatty acids in various free radical reactions (Morehouse, Kiesel, & Ku, 1993).

However, sensory results clearly indicated that the main source of irradiation off-odor was caused by sulfur compounds. All irradiated meat develop a characteristic odor, which has been described as ''metallic'', "sulfide'', "wet dog'', ''wet grain'', or "burnt" (Huber, Brasch, & Waly, 1953), "bloody and sweet'' (Hashim, Resurreccion, & MaWatters, 1995), ''hot fat,'' ''burned oil,'' or ''burned feathers'' (Heath, Owens, Tesch, & Hannah, 1990), and ''barbecued corn-like'' (Ahn, Olson, Jo, Love, & Jin, 1999). The odor intensity of sulfur compounds was much stronger and stringent than that of other compounds because most sulfur compounds have very low-odor thresholds (Lee & Ahn, 2003). Therefore, sulfur compounds would be the major volatile components responsible for the characteristic off-odor in irradiated meat, and volatiles from lipids accounted for only a small part of the off-odor in irradiated meat (Angelini, Merritt, Mendelshon, & King, 1975).

To support the sulfur theory for off-odor production in irradiated meat, studies were conducted using various amino acid homopolymers (Ahn, 2002; Ahn & Lee, 2002). The results indicated that the sulfur compounds produced from irradiated methionine and cysteine had an odor characteristic similar to that of irradiation odor of meat. Sulfur-containing amino acids such as methionine and cystein were the major sources of sulfur volatiles upon irradiation, but the amount of sulfur compounds from cystein was only about 0.25-0.35% of methionine. Therefore, the contribution of methionine to the irradiation odor was far greater than that of cysteine. Other studies on the volatile profiles and sensory characteristics of amino acids clearly indicated that irradiation odor was different from lipid oxidation odor, and lipid oxidation was responsible for only a small part of the off-odor in irradiated meat (Ahn et al., 1999, 2000, 1998).

Mechanisms related to the radiolysis of amino acids are not fully understood, but deamination during irradiation is one of the main steps involved in amino acid radiolysis (Dogbevi, Vachon, & Lacroix, 1999). The degradation of amino acids by oxidative deamination-decarboxylation via the Strecker degradation produces branched chain aldehydes (Mottram, Wedzicha, & Dodson, 2002), which may be the mechanism for the formation of 3-methyl butanal and 2-methyl butanal during irradiation from leucine and isoleucine, respectively (Jo & Ahn, 2000). Davies (1996) reported that irradiation of N-acetyl amino acids and peptides in the presence of oxygen gives high yields of side chain hydroperoxides, which can be formed on both the backbone (at alpha-carbon positions) and the side chains. The interactions among food components such as carbohydrates, lipids, and proteins (Godshall, 1997), and the physicochem-ical conditions of foods, which influence conformation of proteins, also affect the release of volatile compounds in foods (Lubbers, Landy, & Voilley, 1998). This indicated that the relative amounts of volatile compounds released from meat systems could be significantly different from those of the aqueous model systems (Jo & Ahn, 2000).

The color changes in irradiated meat vary significantly depending on various factors such as irradiation dose, animal species, muscle type, and packaging type (Shahidi, Pegg, & Shamsuzzaman, 1991; Luchsinger et al., 1996; Nanke, Sebranek, & Olson, 1999). Generally, irradiation increased redness of light meat such as poultry breast and pork loin (Nam & Ahn, 2002b; Millar, Moss, MacDougall, & Stevenson, 1995; Nam, Ahn, Du, & Jo, 2001), and changes the red color of beef to greenish brown under aerobic conditions, which would be unattractive to consumers (Nam & Ahn, 2003b). Early investigators assumed that the bright red color in light meat after irradiation was oxymyoglobin formed by the reaction between metmyoglo-bin and hydroxyl radicals (Tappel, 1956). Oxymyoglobin was formed by the reduction of heme iron by a radiolytic water product, hydrated electron, and the oxygenation from either residual oxygen or generated oxygen during irradiation (Giddings & Markakis, 1972). However, it is very difficult to accept that the pigment as an oxymyoglobin because the red color formed by irradiation has been produced mainly in anoxic conditions. Millar et al. (1995) postulated that the red/pink color in irradiated light meat was due to a ferrous myoglobin derivative such as carboxyl-myoglobin or nitric oxide-myoglobin other than oxymyoglobin. Nam and Ahn (2002a, 2002b), however, suggested that carbon monoxide-myoglobin (CO-Mb) caused the pink color in irradiated light meat. Considerable amounts of carbon monoxide were produced from organic components such as alcohols, aldehydes, ketones, carboxylic acids, amides, and esters by irradiation (Woods & Pikaev, 1994; Furuta, Dohmaru, Katayama, Toratoni, & Takeda, 1992). Lee and Ahn (2004) reported that glycine, asparagine, glutamine, pyruvate, glyceraldehydes, a-ketoglutarate, and phospholipids were the major sources of CO production among meat components by irradiation.

The decrease of ORP in meat played a very important role in CO-Mb formation because the CO-Mb complex can only be formed when heme pigment is in reduced form (Cornforth, Vahabzadeh, Carpenter, & Bartholomew, 1986). Irradiation lowered oxidation-reduction potential (ORP) in light meat, but the ORP in irradiated meat increased rapidly during storage under aerobic conditions while maintained under vacuum-packaging conditions (Nam & Ahn, 2002b). This result indicated that the increase of ORP facilitated the conversion of myoglobin from ferrous to ferric form, which reduced the affinity of CO to heme pigments, and thus, reduced pink color intensity in meat upon exposure to air. Although, the affinity of CO to Mb is 200-fold higher than that of oxygen (Stryer, 1981), the concentration of oxygen in atmosphere is much higher than that of CO. Therefore, continuous challenge of oxygen under aerobic conditions eventually replaces or removes all CO from heme pigments and reduces the intensity of pink color. In conclusion, three essential factors -production of CO, generation of reducing conditions, and CO-Mb ligand formation - cause the pink color formation of light meats by irradiation. In addition, light meat had higher ferric iron-reducing power than red meat, which facilitated the reduction of heme pigments (Min, Nam, Cordray, & Ahn, 2008).

The mechanisms of color change in irradiated red meat such as beef are different from those of light meats, and the proposed color-changing mechanisms in irradiated beef are as follows: irradiation produces aqueous electrons (eaq-) and hydrogen radicals that have reducing power from water molecules (Thakur & Singh, 1994). Thus, in the absence of O2, a reducing environment is established and all the heme pigments in beef are in ferrous form and color is red (Satterlee, Wilhelm, & Barnhart, 1971). In the presence of oxygen, however, strong-oxidizing agents (superoxide and hydroperoxyl radicals) are formed from the reactions of O2 and eaq- and O2 and H, respectively (Giddings, 1977). Therefore, irradiation under aerobic conditions favors ferric Mb (brown color) but produces ferrous Mb (red color) under vacuum conditions. The content of heme pigments in beef is about 10-times greater than that of light meats, and the proportion of carbon monoxide-myoglobin (CO-Mb), the compound responsible for color changes in irradiated light meats, to total heme pigments in irradiated beef is small. Therefore, overall beef color is mainly determined by the status of heme pigments, which is determined by the reducing potential of meat. Green pigment in irradiated beef was formed by hydrosulfide produced from glutathione or thiol-containing compounds (Fox & Ackerman, 1968).

Irradiation may produce nitric oxide or other precursors to the cured meat pigment, nitrosyl hemochrome, particularly if nitrite or nitrate ions are present (Cornforth et al., 1986). Nitric oxide radical can be generated from nitrogen-containing amino acid side chains (e.g., arginine, glutamine) by an oxidative stress such as irradiation (Thomas, 1999). Packaging environment is an important factor that influences the color of irradiated meat during storage.

Irradiation increased the a*-value (redness) of both aerobically and vacuum-packaged light meats, but the latter was significantly redder than the former during storage (Luchsinger et al., 1997; Nanke et al., 1999; Nanke, Sebranek, & Olson, 1998). Sensory panelists preferred the red color of irradiated light meats to nonirradiated ones because they looked fresh (Lefebvre, Thibault, Charbon-neau, & Piette, 1994). However, increased redness in irradiated meats can be a problem if the red color persists in meat after cooking.

Irradiation significantly increased centrifugation loss of water from pork loins (Zhu, Mendonca, & Ahn, 2004) because of the damage in the integrity of membrane structure of muscle fibers (Lakritz, Carroll, Jenkins, & Maerker, 1987) and the denaturation of muscle proteins, which reduced water-holding capacity (Lynch, Macfie, & Mead, 1991) by irradiation. Transmission electron microscopy showed significant differences in size of myofibril units (sarco-meres) between irradiated and nonirradiated breasts (Yoon, 2003). Lewis, Velasquez, Cuppett, and McKee (2002) found that the texture attributes were lower in irradiated chicken breasts. However, others reported that irradiation had minimal effects on texture of frozen, raw and precooked ground beef patties (Fu et al., 1995), frozen and chilled boneless beef steaks (Luchsinger et al., 1997), and RTE turkey breast rolls (Zhu, Mendonca, Min, et al., 2004).

Consumer acceptance of irradiated meat is important to adopt irradiation technology by meat industries (AMIF, 1993). Despite years of efforts to introduce irradiated foods to marketplace, many consumers still misunderstand the effectiveness, safety, and functional benefits of irradiation technology (Fox, Hayes, & Shogren, 2002). Consumers' willingness to buy irradiated foods varied depending on gender, education level, income, geographic location, and exposure to irradiated food products (Frenzen et al., 2001). The proportion of consumers buying irradiated meat increased after the participants of study received additional information about food irradiation (Hashim et al., 1995), indicating that consumers' knowledge about irradiated foods is among the most important factors for the acceptance of irradiated foods (Lusk, Fox, & Mcllvain, 1999).

Prevention of Quality Changes in Irradiated Meat

Many researchers have studied methods to prevent the quality changes of irradiated meat using various additives and packaging types. Antioxidants, such as ascorbate, citrate, tocopherol, gallic esters, and polyphenols, prevented oxidative rancidity, retarded development of off-flavors, and improved color stability in irradiated fresh and further processed meat (Morrissey, Brandon, Buckley, Sheehy, & Frigg, 1997; Xiong, Decker, Robe, & Moody, 1993; Huber et al., 1953). Meat industries prefer to use natural antioxidants such as rice hull extract, sesamol, and rosemary oleoresin because of consumer demands for natural products and those have effective to reduce off-odor volatiles such as aldehydes and dimethyl disulfide in irradiated turkey meat (Lee, Love, & Ahn, 2003; Nam et al., 2006). Dietary antioxidant treatments for live animal also have shown to reduce the extent of lipid oxidation in irradiated meat during storage (Morrissey et al., 1997; Wen, Morrissey, Buckley, & Sheehy, 1996; Winne & Dirinck, 1996). Lowering pH using acids such as citric and ascorbic acids was expected to decrease redness in irradiated meat because hydroxide anion produced by irradiation was also decreased at low pH status, but it did not affect the redness of irradiated light meat (Nam & Ahn, 2002c). In red meat, however, reducing agent such as ascorbic acid was very effective in maintaining redness and preventing greenish brown discoloration by irradiation (Nam, Min, Park, Lee, & Ahn, 2003). The lowered ORP values by ascorbic acid maintained heme pigments in ferrous status and stabilized the color of irradiated ground beef (Nam & Ahn, 2003b). Addition of antimicrobial agents such as lactate, acetate, and sorbate had synergistic effects with irradiation in killing microorganisms in meat and also had positive effects on the quality of irradiated meat products (Zhu, Mendonca, Min, et al., 2004; Zhu et al., 2005). Therefore, combined use of antimicrobial agents with irradiation can improve the safety of meat products without significant impact on meat quality.

Packaging is an important factor influencing color and volatiles in irradiated meat. Vacuum packaging prevented oxidative changes and color fading in irradiated meat, but retained S-volatiles such as methanethiol, dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide (Nam et al., 2003; Nanke et al., 1999). Aerobic packaging was more desirable for the irradiated meat color, especially in light meat, and off-odor than vacuum packaging if lipid oxidation can be controlled (Ahn, Jo, Olson, & Nam, 2000; Ahn, Nam, Du, & Jo, 2001). Exposing irradiated meat to aerobic conditions for a certain period was helpful in reducing off-color because of competition between atmospheric oxygen and carbon monoxide produced by irradiation and off-odor because of the volatilization of sulfur compounds(Nam & Ahn, 2002a). However, exposing irradiated meats to aerobic conditions increased lipid oxidation (Nam & Ahn, 2003a). Thus, an appropriate combination of aerobic and vacuum packaging, called ''double packaging'', was effective in reducing the generation of off-odor and off-color in irradiated meat during the storage (Nam & Ahn, 2002c). The term ''double packaging'' is to describe a packaging method in which irradiated meat pieces are individually packaged in oxygen-permeable bags (aerobic condition) at first and then a few of aerobic packages are packaged again in a larger vacuum bag (Nam & Ahn, 2003a). If the outer vacuum bag is removed after certain storage time and then displayed under aerobic conditions until the last day of storage, it minimized lipid oxidation, off-odor production, and color change (Nam & Ahn, 2003c).

Although double packaging improved the quality changes of irradiated meat significantly, aldehydes such as propanal and hexanal, which coincided with the degree of lipid oxidation (TBARS) were detected more in double packaging than in vacuum packaging alone. Therefore, the combination of double packaging with antioxidants such as gallate, a-tocopherol, sesamol, and ascorbic acid in irradiated meat was suggested and it was very effective in lipid oxidation as well as reducing off-odor, especially irradiated cooked meat (Nam & Ahn, 2002c, 2003b, 2003c). The combined use of double packaging and ascorbic acid was more effective to irradiated ground beef for maintaining bright red color because irradiating under vacuum condition and added reducing agent was helpful in maintaining low ORP of irradiated beef and caused myoglobin to be remained in a reduced form (Nam & Ahn, 2003b).

Toxicity and Health Concerns

Safety concerns about radiolytic compounds such as furan, 2-alhylcyclobuta-nones (2-ACB), and acrylamide have been raised, despite the fact that only very small amounts of them are present in the irradiated foods. Furan is an aromatic compound found at low concentrations in many irradiated and nonirradiated foods (Maga, 1979) and is considered as a human carcinogen (NTP, 2004). Generally, furan is formed by the thermal decomposition of carbohydrates such as glucose (Walter & Fagerson, 1968) and ascorbic acid (Tatum, Shaw, & Berry, 1969). Therefore, concerns of furan formation in irradiated meat are limited only to RTE products, which contain sugar and ascorbic acid as ingredients and receiving thermal processing. Fan and Sommers (2006) reported that irradiation does not produce furan in RTE meat and poultry products, although furan was formed in aqueous solutions of ingredients used in irradiated RTE meat products and irradiated juices (Fan, 2005).

Acrylamide is known as "a probable human carcinogen" by the International Agency for Research on Cancer (IARC, 1995) and can be formed by Maillard reaction from asparagine and reducing sugars (Yaylayan & Stadler, 2005). Since the Swedish National Food Administration (2002) reported the amount of acrylamide in commonly consumed baked and fried foods, the formation of acrylamide in foods by irradiation has been studied. Fan and Mastovska (2006) reported that irradiation did not induce acrylamide formation in the mixture of reducing sugar and asparagine, but destroyed it in liquid food products.

The toxicological effect of2-alhylcyclobutanones (2-ACB) in irradiated food has been controversial for many years. Since LeTellier and Nawar (1972) reported 2-ACB in highly irradiated synthetic triglycerides, numerous studies on the production of 2-ACB in several irradiated foods, such as chicken, pork beef, fish, egg, cheese, mango and rice have been conducted (Stevenson, 1996; Ndiaye, Jamet, Miesch, Hasselmann, & Marchioni, 1999; Stewart, Moore, Graham, McRoberts, & Hamilton, 2000). Fat is known as the major source of 2-ACB production and irradiation of palmitic, stearic, oleic and linoliec acid produces 2-ACBs such as 2-dodecyl (2-DCB), 2-tetradecyl (2-TCB), 2-tetrade-cenyl (2-TDCB), and 2-tetradecadienyl cyclobutanone (2-TDeCB). Because 2-ACB is not detected in nonirradiated foods, they are also used as markers for irradiated foods. Raul et al. (2002) reported that rats fed 2-TDCB developed tumors in colon and Delincee and Pool-Zobel (1998) reported that 2-DCB caused DNA damage and cell death. However, the amount of 2-ACBs used to induce toxic effects or mutagenecity in animal were thousands times greater than those found in irradiated foods (Health Canada, 2003), and many other recent studies also indicated that the toxicity of 2-ACBs produced in irradiated foods is very low if any (Sommers & Schiestl, 2004; Gadgil & Smith, 2004).

Further Research Needed

Most of the irradiation studies are done with raw meat because irradiation is not permitted for the meats with additives, further processed or precooked ready-to-eat meat products. Therefore, future studies should be focused on flavor, color, and taste changes in further processed and precooked ready-to-eat meat products by irradiation. Methods to prevent quality changes in irradiated further processed or precooked ready-to-eat meat products should also be developed. Although odor and color are important factors for consumer acceptance of irradiated raw meat, the most important quality parameter for cooked meat is taste because if irradiated meat has undesirable taste, consumers will never choose irradiated meat again. Currently, no information on the mechanisms and causes of taste/flavor changes in irradiated cooked meat is available. Therefore, researches to elucidate the causes and mechanisms of taste changes in irradiated cooked meat, determine the roles of spices and additives on taste/flavor of irradiated processed meat, and develop methods that can control taste/flavor changes in irradiated further processed meat are needed. For both raw and cooked meat products, masking of irradiation odor using additives such as natural herb or spices can be an excellent way to solve off-odor problems in irradiated meat. The effect of those additives on the microcidal efficiency of irradiation also should be determined.


Ahn, D. U. (2002). Production of volatiles from amino acid homopolymers by irradiation. Journal of Food Science, 67(7), 2565-2570.

Ahn, D. U., Jo, C., & Olson, D. G. (2000). Analysis of volatile components and the sensory characteristics of irradiated raw pork. Meat Science, 54, 209-215.

Ahn, D. U., Jo, C., Olson, D. G., & Nam, K. C. (2000). Quality characteristics of pork patties irradiated and stored in different packaging and storage conditions. Meat Science, 56, 203-209.

Ahn, D. U., & Lee, E. J. (2002). Production of off-odor volatiles from liposome-containing amino acid homopolymers by irradiation. Journal of Food Science, 67(7), 2659-2665.

Ahn, D. U., Lee, E. J., & Mendonca, A. (2006). Meat decontamination by irradiation. In Advanced technologies for meat processing. Boca Raton, FL: CRC Press, pp. 155-191.

Ahn, D. U., Nam, K. C., Du, M., & Jo, C. (2001). Effect of irradiation and packaging conditions after cooking on the formation of cholesterol and lipid oxidation products in meats during storage. Meat Science, 57, 413-418.

Ahn, D. U., Olson, D. G., Jo, C., Chen, X., Wu, C., & Lee, J. I. (1998). Effect of muscle type, packaging, and irradiation on lipid oxidation, volatile production and color in raw pork patties. Meat Science, 49, 27-39.

Ahn, D. U., Olson, D. G., Jo, C., Love, J., & Jin, S. K. (1999). Volatiles production and lipid oxidation of irradiated cooked sausage with different packaging during storage. Journal of Food Science, 64(2), 226-229.

Ahn, D. U., Olson, D. G., Lee, J. I., Jo, C., Wu, C., & Chen, X. (1998). Packaging and irradiation effects on lipid oxidation and volatiles in pork patties. Journal of Food Science, 63(1), 15-19.

Ahn, D. U., Wolfe, F. H., Sim, J. S., & Kim, D. H. (1992). Packaging cooked turkey meat patties while hot reduces lipid oxidation. Journal of Food Science, 57, 1075-1077, 1115.

AMA (American Medical Association). (1993). Irradiation of food. Council on Scientific Affairs Report 4, Chicago, Ill.

AMIF (American Meat Institute Foundation). (1993). Consumer awareness, knowledge, and acceptance of food irradiation. Washington, DC: American Meat Institute Foundation.

Angelini, P., Merritt, C., Jr., Mendelshon, J. M., & King, F. J. (1975). Effect of irradiation on volatile constituents of stored haddok flesh. Journal of Food Science, 40, 197-199.

Anellis, A., Shattuck, E., Morin, M., Srisara, B., Qvale, S., Rowley, D. B., & Ross Jr., E. W. (1977). Cryogenic gamma irradiation of prototype pork and chicken and antagonistic effect between Clostridium botulinum types A and B. Applied and Environmental Microbiology, 34(6), 823-831.

Aymerich, T., Picouet, P. A., & Monfort, J. M. (2008). Decontamination technologies for meat products. Meat Science, 78, 114 -129.

Brynjolfsson, A. (1989). Future radiation sources and identification of irradiated foods. Food Technology, 43(7), 84-89, 97.

CAST. (1986). Ionizing energy in food processing and pest control: I. Wholesomeness of food treated with ionizing energy (Task Force Report No. 109, p. 50). Ames, IA: Council for Agriculture Science and Technology.

CAST. (1989). Ionizing energy in food processing and pest control: II. Applications (Task Force Report No. 115, pp. 72-76). Ames, IA: Council for Agriculture Science and Technology.

CDCP (Center for Disease Control and Prevention). (2005). Food-borne Illness. http://www.

Champaign, J. R., & Nawar, W. W. (1969). The volatile components of irradiated beef and pork fats. Journal of Food Science, 34, 335-340.

Clavero, M. R., Monk, J. D., Beuchat, L. R., Doyle, M. P., & Brackett, R. E. (1994). Inactivation of Escherichia coli O157:H7, salmonellae, and Campylobacter jejuni in raw ground beef by gamma irradiation. Applied and Environmental Microbiology, 60(6), 2069-2075.

Cornforth, D. P., Vahabzadeh, F., Carpenter, C. E., & Bartholomew, D. T. R. (1986). Role of reduced hemochromes in pink color defect of cooked turkey rolls. Journal of Food Science, 51, 1132-1135.

Davies, M. J. (1996). Protein and peptide alkoxyl radicals can give rise to C-terminal decarboxylation and backbone cleavage. Archives of Biochemistry and Biophysics, 336, 163-172.

Delincee, H., & Pool-Zobel, B. L. (1998). Genotoxic properties of 2-dodecylcyclo-butanone, a compound formed on irradiation of food containing fat. Radiation Physics and Chemistry, 52(1), 39-42.

Diehl, J. F. (1999). Safety of irradiated foods (2nd ed.). New York: Marcel Dekker, Inc.

Dogbevi, M. K., Vachon, C., & Lacroix, M. (1999). Physicochemical and microbiological changes in irradiated fresh pork loins. Meat Science, 51, 349-354.

Dragnic, I. G., & Dragnic, Z. O. (1963). The radiation chemistry of water. New York: Academic Press.

Ehioba, R. M., Kraft, A. A., Molins, R. A., Walker, H. W., Olson, D. G., Subbaraman, G., et al. (1988). Identification of microbial isolates from vacuum-packaged ground pork irradiated at 1 kGy. Journal of Food Science, 53, 278-279, 281.

El-Zawahry, Y. A., & Rowley, D. B. (1979). Radiation resistance and injury of Yersinia enterocolitica. Applied and Environmental Microbiology, 37(1), 50-54.

Fan, X. (2005). Impact of ionizing radiation and thermal treatments on furan levels in fruit juice. Journal of Food Science, 70(7), e409-e414.

Fan, X., & Mastovska, K. (2006). Effectiveness of ionizing radiation in reducing furan and acrylamide levels in foods. Journal of Agriculture and Food Chemistry, 54, 8266-8270.

Fan, X., & Sommers, C. H. (2006). Effect of gamma radiation on furan formation in ready-to-eat products and their ingredients. Journal of Food Science, 71(7), c407-c412.

Fan, X., Sommers, C. H., Thayer, D. W., & Lehotay, S. J. (2002). Volatile sulfur compounds in irradiated precooked turkey breast analyzed with pulsed flame photometric detection. Journal of Agricultural and Food Chemistry, 50(15), 4257-4261.

Farkas, J. (2006). Irradiation for better foods. Trends in Food Science & Technology, 17(4), 148-152.

Federal Register. (1999). Irradiation of meat and meat products. Federal Register, 4, 9089-9105.

Fox, J. B., & Ackerman, S. A. (1968). Formation of nitric oxide myoglobin: Mechanisms of the reaction with various reductants. Journal of Food Science, 33, 364-370.

Fox, J. A., Hayes, D. J., & Shogren, J. F. (2002). Consumer preferences for food irradiation: How favorable and unfavorable descriptions affect preferences for irradiated pork in experimental auctions. Journal of Risk Uncertainty, 24(1), 75-95.

Frenzen, P. D., DeBess, E. E., Hechemy, K. E., Kassenborg, H., Kennedy, M., McCombs, K., et al. (2001). Consumer acceptance of irradiated meat and poultry in the United States. Journal of Food Protection, 64, 2020-2026.

Fu, A. H., Sebranek, J. G., & Murano, E. A. (1995). Survival of Listeria monocytogenes, Yersinia enterocolitica, and Escherichia coli O157:H7 and quality changes after irradiation of beef steak and ground beef. Journal of Food Science, 60, 972-977.

Furuta, M., Dohmaru, T., Katayama, T., Toratoni, H., & Takeda, A. (1992). Detection of irradiated frozen meat and poultry using carbon monoxide gas as a probe. Journal of Agricultural and Food Chemistry, 40(7), 1099-1100.

Gadgil, P., & Smith, J. S. (2004). Mutagenicity and acute toxicity evaluation of 2-dodecylcy-clobutanone. Journal of Food Science, 69(9), c713-c716.

Giddings, G. G. (1977). Symposium: The basis of quality in muscle foods, the basis of color in muscle foods. Journal of Food Science, 42, 288-294.

Giddings, G. G., & Markakis, P. (1972). Characterization of the red pigments produced from ferrimyoglobin by ionizing radiation. Journal of Food Science, 37, 361-364.

Godshall, M. A. (1997). How carbohydrate influence flavor. Food Technology, 51, 63-67.

Grant, I. R., Nixon, C. R., & Patterson, M. F. (1993). Effect of low-dose irradiation on growth of and toxin production by Staphylococcus aureus and Bacillus cereus in roast beef and gravy. International Journal of Food Microbiology, 18(1), 25-36.

Grant, I. R., & Patterson, M. F. (1991). Effect of irradiation and modified atmosphere packaging on the microbiological safety of minced pork under temperature abuse conditions. International Journal of Food Science and Technology, 26, 521-533.

Halliwell, B. J. M., & Gutteridge, C. A. (1989). Consideration of atomic structure and bonding. In B. Halliwell & J. M. C. Gutteridge (Eds.), Free radicals in biology and medicine (2nd ed., pp. 508-524). London: Clarendon Press.

Hashim, I. B., Resurreccion, A. V. A., & MaWatters, K. H. (1995). Disruptive sensory analysis of irradiated frozen or refrigerated chicken. Journal of Food Science, 60, 664-666.

Hastings, J. W., Holzapfel, W. H., & Niemand, J. G. (1986). Radiation resistance of lacto-bacilli isolated from radurized meat relative to growth and environment. Applied and Environmental Microbiology, 52, 898-901.

Hayashi, T. (1991). Comparative effectiveness of gamma rays and electron beams in food irradiation. In S. Thorne (Ed.), Food irradiation (pp. 169-206). London: Elsevier Applied Science.

Health Canada. (2003). Evaluation of the significance of 2-dodecylcyclobutanone and other alkylcyclobutanones. Ottawa,

Heath, J. L., Owens, S. L., Tesch, S., & Hannah, K. W. (1990). Effect of high-energy electron irradiation of chicken on thiobarbituric acid values, shear values, odor, and cook yield. Poultry Science, 69, 313-319.

Huber, W., Brasch, A., & Waly, A. (1953). Effect of processing conditions on organoleptic changes in foodstuffs sterilized with high intensity electrons. Food Technology, 7, 109-115.

Huhtanen, C. N., Jenkins, R. K., & Thayer, D. W. (1989). Gamma radiation sensitivity of Listeria monocytogenes. Journal of Food Protection, 9, 610-613.

IAEA. (1999). Facts about food irradiation. Accessed July 8, 1999, from International Atomic Energy Agency, Vienna, Austria

IARC (International Agency for Research on Cancer). (1995). IARC monographs on the evaluation of carcinogenic risks to humans: Some industrial chemicals (IARC 60, pp. 389-433). Lyon, France: IARC.

Jarrett, R. D., Sr. (1982). Isotope (gamma) radiation sources. In E. S. Josephson & M. S. Peterson (Eds.), Preservation of food by ionizing radiation (Vol. 1, pp. 137-163). Boca Raton, FL: CRC Press.

Jo, C., & Ahn, D. U. (2000). Production of volatiles from irradiated oil emulsion systems prepared with amino acids and lipids. Journal of Food Science, 65(4), 612-616.

Josephson, E. S., & Peterson, M. S. (2000). Preservation of food by ionizing radiation (II) (pp. 102-103). Boca Raton, FL: CRC Press.

Karel, M. (1989). The future of irradiation applications on earth and in space. Food Technology, 41(7), 95-97.

Kawakishi, S., Okumura, J., & Namki, M. (1971). Gamma radiolysis of carbohydrate in aqueous solution. Food Irradiation, 6, 80-86.

Lagunas-Solar, M. C. (1995). Radiation processing of food: An overview of scientific principles and current status. Journal of Food Protection, 58, 186-192.

Lakritz, L., Carroll, R. J., Jenkins, R. K., & Maerker, G. (1987). Immediate effects of ionizing-radiation on the structure of unfrozen bovine muscle-tissue. Meat Science, 20, 107-117.

Lambert, A. D., Smith, J. P., & Dodds, K. L. (1992). Physical, chemical, and sensory changes in irradiated fresh pork packaged in modified atmosphere. Journal of Food Science, 57, 1294-1299.

Lee, E. J., & Ahn, D. U. (2003). Production of off-odor volatiles from fatty acids and oils by irradiation. Journal of Food Science, 68(1), 70-75.

Lee, E. J., & Ahn, D. U. (2004). Sources and mechanisms of carbon monoxide production by irradiation. Journal of Food Science, 69(6), c485-c490.

Lee, E. J., Love, J., & Ahn, D. U. (2003). Effect of antioxidants on the consumer acceptance of irradiated turkey meat. Journal of Food Science, 68(5), 1659-1663.

Lefebvre, N., Thibault, C., Charbonneau, R., & Piette, J. P. G. (1994). Improvement of shelf-life and wholesomeness of ground beef by irradiation 2: Chemical analysis and sensory evaluation. Meat Science, 36, 371-380.

LeTellier, P. R., & Nawar, W. W. (1972). 2-Alkylcyclobutanones from radiolysis of triglycerides. Lipids, 7, 75-76.

Lewis, S. J., Velasquez, A., Cuppett, S. L., & McKee, S. R. (2002). Effect of electron beam irradiation on poultry meat safety and quality. Poultry Science, 81, 896-903.

Loaharanu, P. (1994). Status and prospects of food irradiation. Food Technology, 48(5), 124-130.

Lubbers, S., Landy, P., & Voilley, A. (1998). Retention and release of aroma compounds in foods containing proteins. Food Technology, 52, 68-74, 208-214.

Luchsinger, S. E., Kropf, D. H., Garcia-Zepeda, C. M., Hunt, M. C., Marsden, J. L., Rubio-Canas, E. J., et al. (1996). Color and oxidative rancidity of gamma and electron beam irradiated boneless pork chops. Journal of Food Science, 61(5), 1000-1005, 1093.

Luchsinger, S. E., Kropf, D. H., Garcia-Zepeda, C., Hunt, M. C., Stroda, S. L., Marsden, J. L., et al. (1997). Color and oxidative properties of irradiated ground beef patties. Journal of Muscle Foods, 8(4), 445-464.

Lusk, J. L., Fox, J. A., & McIlvain, C. L. (1999). Consumer acceptance of irradiated meat. Food Technology, 53, 56-59.

Lynch, J. A., Macfie, H. J. H., & Mead, G. C. (1991). Effect of irradiation and packaging type on sensory quality of chill-stored turkey breast fillets. International Journal of Food Science and Technology, 26, 653-668.

Maga, J. A. (1979). Furans in foods. CRC Critic Review in Food Science and Nutrition, 1, 355-400.

Mason, J. (1992). Food irradiation - Promising technology for public health (pp. 489-490). Public Health Report, 107.

Mead, P. S., Slutsker, L., Dietz, V., McCaig, L. F., Bresee, J. S., Shapiro, C., et al. (1999). Food related illness and death in the United States. Emerging Infectious Diseases, 5(5), 607-625.

Merritt, C., Jr., Angelini, P., & Graham, R. A. (1978). Effect of radiation parameters on the formation of radiolysis products in meat and meat substances. Journal of Agricultural and Food Chemistry, 26, 29-36.

Merritt, C., Jr., Angelini, P., Wierbicki, E., & Shuts, G. W. (1975). Chemical changes associated with flavor in irradiated meat. Journal of Agricultural and Food Chemistry, 23, 1037-1043.

Millar, S. J., Moss, B. W., MacDougall, D. B., & Stevenson, M. H. (1995). The effect of ionizing radiation on the CIELAB color co-ordinates of chicken breast meat as measured by different instruments. International Journal of Food Science and Technology, 30, 663-674.

Min, B., Nam, K. C., Cordray, J., & Ahn, D. U. (2008). Endogenous factors affecting oxidative stability of beef loin, pork loin, and chicken breast and thigh meats. Journal of Food Science, 73(6), C 439-C446.

Minsch, F. (1896). Munch Med Wochensch, 5, 101, 109, 202.

Monk, J. D., Clavero, M. R. S., Beuchat, L. R., Doyle, M. P., & Brackett, R. E. (1994). Irradiation inactivation of Listeria monocytogenes and Staphylococcus aureus in low- and high-fat, frozen and refrigerated ground beef. Journal of Food Protection, 57, 969-974.

Morehouse, K. M., Kiesel, M., & Ku, Y. (1993). Identification of meat treated with ionizing radiation by capillary gas-chromatographic determination of radiolytically produced hydrocarbons. Journal of Agricultural and Food Chemistry, 41, 758-763.

Morrissey, P. A., Brandon, S., Buckley, D. J., Sheehy, P. J. A., & Frigg, J. (1997). Tissue content of a-tocopherol and oxidative stability of broilers receiving dietary a-tocopheryl acetate supplementation for various periods pre-slaughter. British Poultry Science, 38, 84-88.

Mottram, D. S., Wedzicha, B. L., & Dodson, A. T. (2002). Acrylamide is formed in the Maillard reaction. Nature, 419, 448-449.

Nam, K. C., & Ahn, D. U. (2002a). Carbon monoxide-heme pigment complexes are responsible for the pink color in irradiated raw turkey breast meat. Meat Science, 60(1), 25-33.

Nam, K. C., & Ahn, D. U. (2002b). Mechanisms of pink color formation in irradiated precooked turkey breast. Journal of Food Science, 67(2), 600-607.

Nam, K. C., & Ahn, D. U. (2002c). Effect of double-packaging and acid combination on the quality of irradiated raw turkey patties. Journal of Food Science, 67(9), 3252-3257.

Nam, K. C., & Ahn, D. U. (2003a). Combination of aerobic and vacuum packaging to control color, lipid oxidation and off-odor volatiles of irradiated raw turkey breast. Meat Science, 63(3), 389-395.

Nam, K. C., & Ahn, D. U. (2003b). Effects of ascorbic acid and antioxidants on the color of irradiated beef patties. Journal of Food Science, 68(5), 1686-1690.

Nam, K. C., & Ahn, D. U. (2003c). Use of double-packaging and antioxidant combinations to improve color, lipid oxidation, and volatiles of irradiated raw and cooked turkey breast patties. Poultry Science, 82(5), 850-857.

Nam, K. C., Ahn, D. U., Du, M., & Jo, C. (2001). Lipid oxidation, color, volatiles, and sensory characteristics of aerobically packaged and irradiated pork with different ultimate pH. Journal of Food Science, 66, 1225-1229.

Nam, K. C., Ko, K. Y., Min, B. R., Ismail, H., Lee, E. J., & Ahn, D. U. (2006). Influence of rosemary-tocopherol/packaging combination on the chemical quality and Listeria monocytogenes and Salmonella typhimurium survival in restructured pork loins following electron irradiation. Meat Science, 74(2), 380-387.

Nam, K. C., Min, B. R., Park, K. S., Lee, S. C., & Ahn, D. U. (2003). Effects of ascorbic acid and antioxidants on the lipid oxidation and volatiles of irradiated beef patties. Journal of Food Science, 68(5), 1680-1685.

Nanke, K. E., Sebranek, J. G., & Olson, D. G. (1998). Color characteristics of irradiated vacuum-packaged pork, beef, and turkey. Journal of Food Science, 63(6), 1001-1006.

Nanke, K. E., Sebranek, J. G., & Olson, D. G. (1999). Color characteristics of irradiated aerobically packaged pork, beef, and turkey. Journal of Food Science, 64, 272-276.

NAPPO (North American Plant Protection Organization). (1995). Proceedings of the North American Plant Protection Organization annual meeting colloquium on the application of irradiation technology as a quarantine treatment (pp. 62-65). Neapean, Ontario, Canada; NAPPO bulletin No. 13.

Nawar, W. W. (1986). Volatiles from food irradiation. Food Review International, 2(1), 45-78.

Ndiaye, B., Jamet, G., Miesch, M., Hasselmann, C., & Marchioni, E., (1999). 2-Alkylbuta-nones as markers for irradiated foodstuffs. II. The CEN (European Committee for Standardization) method: Field of application and limit of utilization. Radiation Physics and Chemistry, 55, 437-445.

NTP (National Toxicology Program). (2004). Report on carcinogens (11th ed., Furan CAS No. 110-00-9). Research Triangle Park, NC: U.S. Dept. of Health and Human Services, Public Health Service,

Olson, D. G. (1998a). Irradiation of food. Food Technology, 52, 56-62.

Olson, D. G. (1998b). Irradiation processing. In E. Murano (Ed.), Food irradiation - A sourcebook. Meat and poultry irradiation short course (pp. 3-27). Ames, IA: Iowa State University Press.

Patterson, M. (1988). Sensitivity of bacteria to irradiation on poultry meat under various atmospheres. Letters of Applied Microbiology, 7, 55-58.

Palumbo, S. A., Jenkins, R. K., Buchanan, R. L., & Thayer, D. W. (1986). Determination of irradiation D-values for Aeromonas hydrophila. Journal offood protection, 49(3), 189-191.

Raul, F., Gosse, F., Delinceee, H., Hartwig, A., Marchioni, E., Miesch, M., et al. (2002). Foodborne radiolytic compounds (2-alkycylobutanones) may promote experimental colon carcinogenesis. Nutrition and Cancer, 44(2), 189-191.

Satin, M. (2002). Use of irradiation for microbial decontamination of meat: Situation and perspectives. Meat Science, 62, 277-283.

Satterlee, L. D., Wilhelm, M. S., & Barnhart, H. M. (1971). Low dose gamma irradiation of bovine metmyoglobin. Journal of Food Science, 36(3), 549-551.

Schwartz, B. (1921). Effect of X-rays on Trichinae. Journal of Agricultural Research, 20, 845-849.

Shahidi, F., & Pegg, R. B. (1994). Lipids infoodflavors (ACS Symposium Series 558, pp. 256-279). Washington, DC: American Chemical Society.

Shahidi, F., Pegg, R. B., & Shamsuzzaman, K. (1991). Color and oxidative stability of nitritefree cured meat after gamma irradiation. Journal of Food Science, 56, 1450-1452.

Shamsuzzaman, K., & Lucht, L. (1993). Resistance of Clostridium sporogenes spores to radiation and heat in various nonaqueous suspension media. Journal of Food Protection, 56(1), 10-12.

Sommers, C. H. (2004). Food irradiation is already here. Food Technology, 58(11), 22.

Sommers, C. H., & Schiestl, R. H. (2004). 2-Dodecylcyclobutanone does not induce mutations in the Salmonella mutagenicity test or intrachromosomal recombinations in Sacc-charomyces cerevisiae. Journal of Food Protection, 67, 1293-1298.

Steccheni, M. I., Del Torre, M., Sarais, P. G., Fuochi, F., Tubaro, F., & Ursini, F. (1998). Carnosine increases the radiation resistance of Aeromonas hydrophila in minced turkey meat. Journal of Food Science, 61, 979-987.

Stevenson, M. H. (1996). Validation of the cyclobutanone protocol for detection of irradiated lipid containing foods by interlaboratory trial. In C. H. McMurray, E. M. Stewart, R. Gray, & J. Pearce (Eds.), Detection methods for irradiated foods - Current status (pp. 269-284). Cambridge, UK: Royal Society of Chemistry.

Stewart, E. M., Moore, S., Graham, W. D., McRoberts, W. C., & Hamilton, J. T. G. (2000). 2-Alkylcyclobutanones as markers for the detection of irradiated mango, papaya, camembert cheese and salmon meat. Journal of Science and Food Agriculture, 80, 121-130.

Stryer, L. (1981). Biochemistry (p. 54). New York: Freeman and Co.

Swedish National Food Administration. (2002). Information about acrylamide in food. Uppsala, Sweden: Swedish NFA,

Tappel, A. L. (1956). Regeneration and stability of oxymyoglobin in some gamma irradiated meats. Food Research, 21, 650-654.

Tatum, J. H., Shaw, P. E., & Berry, R. E. (1969). Degradation products from ascorbic acid. Journal of Agriculture and Food Chemistry, 17, 38-40.

Taub, I. A., Karielian, R. A., & Halliday, J. W. (1978). Radiation chemistry of high protein food irradiated at low temperature. In Food preservation by irradiation (Vol. 1, pp. 371-384). Vienna: International Atomic Energy Agency.

Taub, I. A., Karielian, R. A., Halliday, J. W., Walker, J. E., Angeline, P., & Merritt, C. (1979). Factors affecting radiolytic effects of food. Radiation Physics and Chemistry, 14, 639-653.

Thakur, B. R., & Singh, R. K. (1994). Food irradiation: Chemistry and applications. Food Review International, 10, 437-473.

Thayer, D. W. (1995). Use of irradiation to kill enteric pathogens on meat and poultry. Journal of Food Safety, 15, 181-192.

Thayer, D. W., & Boyd, G. (1992). Gamma ray processing to destroy Staphylococcus aureus in mechanically deboned chicken meat. Journal of Food Science, 57(4), 848-851.

Thayer, D. W., & Boyd, G

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