Anon. 1993. Consultants' meeting on irradiation for shelf-stable
foods. In. Consultants' meeting on irradiation for shelf-stable foods,
A consultants meeting on irradiation for shelf-stable foods was convened to evaluate the role of irradiation in increasing the availability, improving the quality and reducing the cost of shelf-stable foods; also to consider the need for a research and development program to be carried out by the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture.
Anon. 1985. Irradiation in the production processing and
handling of food: Final rule. 21 CFR Part 179. Federal Regis. 50(140):
The U.S. Food and Drug Administration approved treatment of pork meat and products with a minimum dose of 0.3 kGy and a maximum of 1.0 kGy of ionizing radiation to control Trichinella spiralis.
Anon. 1986. Irradiation of pork for control of Trichinella
spiralis. 9 CFR Part 318. Federal Regis. 51(10): 1769.
The USDA Food Safety and Inspection Service approved the processing regulation for treatment of pork meat and products with a minimum dose of 0.3 kGy and a maximum of 1.0 kGy of ionizing radiation to control Trichinella spiralis.
Anon. 1990. Dept. of Health and Human Services Food and
Drug Administration. 21 CFR, part 179 final rule; irradiation in the production
processing and handling of food. Fed. Regist., 55 55(18538-18544.).
Approval of ionizing radiation treatments of poultry to eliminate foodborne pathogens.
Anon. 1992. Department of Agriculture Food Safety and
Inspection Service 9CFR Part 381 final rule: irradiation of poultry products.
Fed. Regist., 57 57: 435888-43600.
The regulation for irradiation of poultry products from the USDA Food Safety and Inspection Service requires minimum and maximum doses of 1.5 and 3.0 kGy (1 kGy = 100 kilorads) respectively.
Anon. 1993. WHO backs food irradiation to destroy diseases.
(News Release No. Reuters Information Services Inc.
The World Health Organization (WHO) called on Tuesday for greater use of irradiation to destroy diseases including cholera, salmonella, and listeria in food. The UN agency said illness due to contaminated food was perhaps the most widespread health problem globally and repeated its view that the controversial process of exposing food to gamma rays or x-rays was safe. The Geneva-based agency acknowledged that the technique remained a "hotly-debated issue in many countries" and that there were relatively few irradiated foods on the market. Some consumers' organizations have opposed the process expressing doubts about various safety and nutritional aspects.
Best, D. 1989. Marketing irradiation. Prepared Foods.
Mounting consumer awareness of the seriousness of foodborne illness and microbial contamination of poultry offers the food industry a clear-cut opportunity to present its case in support of food irradiation. Past experience has demonstrated that education can work, but government and industry must take care to address very legitimate consumer concerns about irradiation in a straight-forward fashion. Consumer education is the foremost prerequisite of any irradiation market program. The message must be presented in simple, straightforward terms, however.
Beuchat, L. R., Doyle, M.P., and Brackett, R.E. 1993.
Irradiation inactivation of bacterial pathogens in ground beef. American
Meat Institute Foundation.
Experiments were done to determine the D10 kGy of Escherichia coli O157:H7, Salmonella, Campylobacter jejuni, Listeria monocytogenes, and Staphylococcus aureus in uncooked ground beef. The influence of two levels of fat (8 to 14% and 27 to 28%) and temperature (frozen [ -17 to -15°C (1 to 5°F)] and refrigerated [ -3 to 5°C (37 to 41°F)]) during gamma irradiation (Cobalt 60) was studied. Cells of all test pathogens were in the stationary phase of growth when inoculated into ground beef before subjecting to seven target irradiation doses ranging from 0 to 3.0 kGy. E. coli O157:H7 had a significantly higher D10 value when irradiated at -17 to -15°C compared to treatment at 3 to 5°C. At a given temperature, the level of fat in beef did not have an effect on D10 values. Salmonella behaved similarly to E. coli O157:H7 in low fat beef, but temperature had no effect on D10 values when the pathogen was irradiated in high-fat beef. Significantly higher D10 values were calculated for C. jejuni in frozen compared to refrigerated low-fat beef. The pathogen was more resistant to irradiation in low-fat beef when treatment was done at -17°C to -15°C. Neither the level of fat nor the treatment temperature significantly affected the D10 values for L. monocytogenes and S. aureus. Considering all combinations of fat level and treatment temperature, the ranges of D10 values (kGy) were, in ascending order of irradiation resistance: C. jejuni, 0.175 to 0.235; E. coli O157:H7, 0.241 to 0.307; S. aureus, 0.435 to 0.453; L. monocytogenes, 0.507 to 0.610; and Salmonella, 0.618 to 0.800. Research was conducted at the Center for Food Safety and Quality Enhancement, University of Georgia in collaboration with Vindicator, Inc., Mulberry, FL.
Blackholly, H., and Thomas, P. 1989. Food Irradiation.
Bradford, U.K., Horton Publishing Ltd.
This publication examines food irradiation in the context of UK and EC legislation, its technological implication and consumer, retailer and manufacturer attitudes. It provides a clean introduction to the food retailer or manufacturer interested in future commercial prospects in this area.
Boisseau, P. 1994. Irradiation and the food industry in
France. Food Technol. 48 (5) 138-140.
Transfer of technology from government and academia to the food industry in France has resulted in successful commercialization of irradiation.
Bruhn, C. M., and Schutz, H.G. 1989. Consumer awareness
and outlook for acceptance of food irradiation. Food Technol. 43(7): 93-94.
Consumer acceptance or rejection: Rejectors are opposed to irradiation for personal beliefs, such as the desire to eat only natural, unprocessed, or "organic" foods. About 5 to 10% of the population are irradiation rejectors. About half of the population are undecided. These people are unsure in their knowledge and understanding of the irradiation technology. Their concerns include food's safety, quality and nutritional value. The acceptors, estimated to be from 25 to 30% of the population, believe they understand the process of irradiation and accept that irradiated foods are safe and nutritious. Accepting consumers trust the FDA and food manufacturers. To be acceptable, irradiation must offer to the consumer an advantage. This advantage could be higher quality, greater safety, longer shelf life, wide product availability, or lower cost. All consumers wanted products labeled for various reasons. Some, so they could avoid them, others, to they could choose them and realize the advantage they thought the process offered. Others simply want to know what they are buying. Some people believe that non-labeling implies information about the product is hidden. The consumer needs to be educated and informed. Information may not reduce consumer concern, but it allows choice to be based on fact, rather than suspicion. Consumer attitude and marketing studies show that given information about irradiation, the majority will choose irradiated foods. Others object to irradiation and will never select it. The opportunity for choice in the marketplace should exist. "The eventual utilization of this technology will depend upon the safety of alternative technologies, industry's perception of potential success, responsible media coverage, and consumer information."
Brynjolfsson, A. 1985. Wholesomeness of irradiated
foods: A review. J. Food Safety 7: 107-126.
The major findings in the wholesomeness studies on irradiated foods are reviewed. It is concluded that this process is ready for industrial applications and could be effectively regulated for the benefit of the consumer.
Brynjolfsson, A. 1989. Future radiation sources and identification
of irradiated foods. Food Technol. 43(7): 84-89, 97.
Discusses sources used to irradiate foods. Discusses how irradiated foods can be identified by evaluating chemical changes, physiological changes, microbial changes and morphological changes through lyoluminescence and thermoluminescence.
CAST. 1986. Ionizing Energy in Food Processing and
Pest Control: I. Wholesomeness of Food Treated with Ionizing Energy. Council
for Agricultural Science and Technology. Ames, Iowa. 50 pages.
Abstract not prepared.
Clarke, S., and Riley, J. 1993. The more consumers learn
about irradiation, the more they want it. American Meat Institute.
New study shows consumers lack knowledge; support irradiation once they understand it. A new study conducted by the Gallup organization, confirms that the more consumers know about food irradiation, the more likely they are to desire it for destroying bacteria in poultry, pork, beef and seafood. Although 73% of Americans have heard about food irradiation, only 24% claim to have any knowledge of the process. After the benefits of irradiation are explained and endorsements from health organizations are mentioned, over half (54 percent) of those interviewed say they would purchase irradiated meat rather than non-irradiated meat. Further, 60% said they would be willing to pay a 5% premium for irradiated hamburger. Men and those who had experienced foodborne illnesses are most accepting of irradiated foods. Consumers generally do not understand the food safety benefits of most food preservation technologies -- including pasteurization, canning and freezing. In a simulated supermarket setting study conducted by the University of Georgia, 50% of consumers tested chose irradiated ground beef over regular ground beef. After all consumers tested learned more about the irradiation process and how it affects raw meats, those choosing irradiated beef increased to 70% of the sample size.
Conley, S. T. 1992. What do consumers think about irradiated
foods. FSIS Food Safety Review(Fall): 11-15.
There is the perception that the public, reacting to a distrust of anything even remotely related to nuclear energy will never buy or accept irradiated food, therefore, in response to this perception of consumer fear, no industry has been willing to sell irradiated food until recently. Consumers are not likely to demand food irradiation now because they don't know enough about it. But they are demanding safer food. Food safety is an area of consumer, industry, and government concern. Irradiation of meat, poultry, fruits and vegetables at appropriate levels could control many organisms that cause foodborne illness and product spoilage. Thus, food irradiation could be a viable process that could improve safety and extend shelf-life. The Codex Alimentarius Commission, the World Health Organization, the federal government, and more than 35 foreign countries have endorsed the safety of food irradiation. 14 of 35 foreign countries have approve poultry irradiation. Market tests in Florida indicate consumer acceptance of irradiated mangoes, papayas, apples and strawberries. A 1988 study conducted by a USDA Economic Research Service economist and a University of Florida professor found that consumers are willing to pay more for a safer product and would buy irradiated chicken. However, there are anti-food radiation activists. At this time some supermarket chains and grocery retailers are reluctant to offer irradiated foods for sale, fearing customer boycotts. Education is the key. Proponents of food irradiation firmly believe these foods will be accepted when offered for sale. But it won't be easy. If half the population is undecided about the process, and studies show that information and education can increase consumer acceptance, why aren't massive amounts of information available? Answer: The industry, not wanting to appear prejudiced and fearing reprisals from interest groups, has been reluctant to produce consumer-oriented materials. The federal government thus far has taken the position that, while the process is safe and should be available to the industry and consumers, the government should not be viewed as a proponent of the process. As a result, there is very little consumer-oriented material available about irradiated food or the process. Into this void, step activist groups, some of which provide information and material than can increase fear of irradiated food products. Responsible government provides information to help consumers make educated choices, not choices based on limited information and fear tactics. Author advocates that the FSIS and the National Agricultural Library in cooperation with other food related agencies such as the FDA should provide education materials to consumers regarding food irradiation.
Derr, D. 1993. Radiation Processing. ASTM Standardization
News 21(7): 25-27.
Discussion of the current status of food irradiation in the U.S. Article points out that "Food irradiation will be successful only is regulators, industry and consumers agree that it is safe and effective. Appropriate control and inspection procedures are important aspects of that agreement. ASTM standards are being developed using "Codes of Good Irradiation Practice" developed by the International Consultative Group on Food Irradiation (ICGFI). This will facilitate acceptance of irradiated foods in international trade.
Diehl, J. F. 1995. Safety of Irradiated Foods. Marcel
Dekker, Inc., New York, NY. (454 pages)
Abstract not prepared.
Dupont, H. L. 1992. How safe is the food we eat? J. Am.
Med. Assoc. 268(22): 3240.
Discusses the potential of transmission of bacterial enteropathogens (Salmonella, Shigella, Campylobacter, Vibrios) through food vehicles destined for human consumption. Recommends improving the microbiological safety of food through irradiation. Future health hazards may be reduced if this technique is employed widely for certain high-risk items, including poultry potentially contaminated with Salmonella and Campylobacter.
Elias, P. S. 1989. New concepts for assessing the wholesomeness
of irradiated foods. Food Technol., 43(7): 81-83.
Radiochemical considerations and short-term mutagenicity screening tests replace extensive animal feeding studies formerly required for safety assessment. The assessment of the safety for human consumption of irradiated foodstuffs involves basically four aspects: 1) radiological safety; 2) microbiological safety; 3) nutritional adequacy; 4)toxicological safety. Toxicological safety is discussed in this article because most of the new concepts for assessing wholesomeness have been developed in the field of the toxicological investigation of irradiated foodstuffs.
FDA. 1990. Irradiation in the production, processing and
handling of food: labeling. Fed. Register. 55(5): 646.
Approved use of irradiation for controlling bacterial contamination in chicken, turkey, and other fresh and frozen uncooked poultry.
Food Production and Inspection Branch Agriculture Canada.
1989. Food irradiation update. Safety Watch - Food-borne Disease Bulletin
On March 23, 1989, Food and Drug Regulations of Canada were amended to create a new division for the specific control of food irradiation. Food irradiation has been regulated for more than 20 years under food additive provisions of Division 16. The new division, Division 16 is called Food Irradiation. It recognizes food irradiation as a process and contains regulations that are meaningful and specific. The new regulations define "ionizing radiation" and control the sources used in the process: set out requirements for record keeping, thereby strengthening inspection and compliance programs; and detail the pre-clearance requirements to be met before regulatory consideration is given to any additional or extended uses of food irradiation or changes in radiation sources or dosages. Canada agrees with the Codex Alimentarius Commission, which in 1983 took the position that foods irradiated below 10 kGy present no toxicological hazard. To ensure that consumers have the information necessary to choose between irradiated and non-irradiated food, Canada's food irradiation regulations state that irradiated foods be clearly marked with the international symbol for irradiated foods, and carry a statement to the effect that the food has been irradiated. When an irradiated food is used as an ingredient constituting 10% or more of a finished product, it must be described as "irradiated in the ingredient list."
Food Safety and Inspection Service. 1992. Poultry irradiation
and preventing foodborne illness. Washington, D.C., U.S.D.A., F.S.I.S.
Discussion of poultry irradiation, labeling, protection of employees and inspectors, inspection of facilities.
Fox, J. B., D. W. Thayer, R. K. Jenkins, S. A. Ackerman,
J. G. Phillips, G.R. Beecher, J. Holden, F. D. Morrow, and D. M. Quirback.
1989. Effect of gamma irradiation on B vitamins of pork chops and chicken
breasts. In. J. Radiat. Biol. 55: 689-703.
Abstract not prepared.
Fox, J. B., Ackerman, S., and Thayer, D.W. 1992. The effect
of radiation scavengers on the destruction of thiamin and riboflavin in
buffers and pork due to gamma irradiation. Prehrambeno-tehnol. biotehnol.
biotehnol. rev. 30(4): 171-175.
Free radical scavengers were tested for their ability to reduce the loss of thiamin and riboflavin in buffered solutions and in pork during gamma irradiation. In aqueous solution, the tested compounds were twice as effective for the protection of riboflavin as for the protection of thiamin. The presence of nitrous oxide doubled the rates of loss for thiamin and riboflavin in solution, indicating a predominance of reactions with hydroxyl radicals. In buffered solutions, niacin was not affected by gamma radiation unless either thiamin or riboflavin was present, in which case the niacin was destroyed rather than the other vitamin. Ascorbate, cysteine, and quinoid reductants were demonstrated to be naturally present in sufficient quantities to account for the lower rates of loss of thiamin and riboflavin observed during irradiation of pork meat as compared to irradiation in buffered solution.
Fox, J. B., Lakritz, L., and Thayer, D.W. 1993. Effect
of reductant level in skeletal muscle and liver on the rate of loss of
thiamin due to gamma-irradiation. Int. J. Radiat. Biol. 64(3): 305-309.
A study was made of thiamin content of the skeletal muscles and livers of pork, chicken, and beef after gamma-irradiation. Gamma radiation from a Cesium 137 source was used to irradiate the samples with doses of 0, 1.5, 3, 6, and 10 kGy at 2°C. Samples were also titrated with dichlorophenoindophenol to determine the reducing capacity of the tissue. The rate of loss of thiamin upon irradiation was found to be about 3 times as fast in skeletal muscle as in liver and to be a function of the reducing capacity of the tissues, the loss decreasing with increasing reductant titer. For the same amount of thiamin loss, liver could be irradiated to 3 times the dose as could muscle.
Frazer, W. C., and Westhoff, D.C. 1988. Chapter 10. Preservation
by radiation. Food Microbiology. New York, N.Y., McGraw Hill: 159-170.
Good review of the factors involved with the irradiation pasteurization and sterilization of food.
Fumento, M. 1994. To save lives with safer food. Washington
Times. Washington, D.C.: 15.
Irradiation will give food producers another line of defense in preventing foodborne illness, and to prevent its use is to deny them a valuable tool in protecting public health. The U.S. Secretary of Agriculture has asked the Food and Drug Administration to approve the use of irradiation on beef. There are many activists who oppose the use of radiation for food. Instead of using irradiation to enhance food safety, opponents say the answer is increased government regulation, especially increasing the size of the government's meat inspection force. At this time, the government employs only about 8,000 inspectors, including supervisors, for about 32 million head of slaughtered cattle annually. However, inspectors cannot see bacteria and other spoilage organisms and no microbiological tests currently exist that would make it practical to perform routine laboratory analysis on raw meat.
Gallager, D., and Kwittken, A. 1994. Current meat inspection
system "insufficient" for ensuring food safety, independent panel says.
American Gastroenterological Association Foundation.
Reports conclusions of an E. coli O157:H7 Consensus Development Conference. "Protection of the public's health requires the immediate implementation of currently recognized scientific technology for ensuring food safety. an emphasis should be placed on science-based monitoring and verification of the nation's slaughter plant operations. The current inspection-based system should be replaced by a science-based risk assessment process with government verification. The 14 member nonadvocate panel was comprised of professionals and public representatives from gastroenterology, epidemiology, public health, microbiology, food science, industry and consumer affairs. Speakers included scientific investigators, government representatives, industry officials, and consumers. One of the major recommendations made was that "Irradiation pasteurization is a safe and effective intervention strategy, especially in ground beef and should be implemented as soon as possible."
Gibson, R. 1994. Beef irradiation meets politics in Washington.
Wall Street Journal. New York, N.Y.: B1, B3.
Irradiating beef may help save lives, but the meat industry is still waiting for the green light. Agriculture scientists report that small doses of irradiation could wipe out "nearly 100% of the E. coli strain in beef and has been shown to sterilize meat and produce against practically all bacterial that cause spoilage. Yet, the Department of Agriculture is holding back because of the concern that the public might link beef irradiation with the government radiation experiments of the 1950's. Irradiation Statistics What it is: Short bursts of gamma rays from radio active isotopes cobalt 60 and cesium 137, or from electron beams. What it does: Removes almost all traces of E. coli in beef, Salmonella in poultry, cholera in fish, trichinosis in pork and bacteria that spoil produce. Proponents of Beef Irradiation: The National Food Processors Association, the American Medical Association, the World Health Organization, and the American Meat Institute. All say beef irradiation will help reduce deaths from E. coli. Critics of Beef Irradiation: Food and Water, Inc. They say nutrients are lost in the process and not enough is known about the stray molecules that result from it. Because irradiation is considered a food additive-although it leaves not traces and is usually undetectable-the FDA by law must approve the technique for beef, as it has for poultry. But the FDA can't act until the USDA, which oversees the nations food supply recommends it do so.
Hall, R. L. 1989. Commercialization of the food irradiation
process. Food Technol. 43(7): 90-92.
Decisions by food processor to invest - or not to invest - in radiation processing depend on many factors. Some of these rarely receive much attention in discussions of the subject. In the Netherlands, commercial food irradiation is routinely applied to a broad range of products, however, nowhere else has food irradiation achieved this goal. Regulatory and safety aspects of the process, equipment and cost factors, and obtaining consumer acceptance are factors which have contributed to the slowness of commercialization of food irradiation. When whether or not to develop a food irradiation process, the processor must ask: 1) Will irradiation serve my particular needs? 2) How much will it cost? 3) Is it safe for consumers, customers, employees? 4) What regulations will apply, how much trouble will they be, and what will they cost me? 5) What public relations aspects, including community attitudes, will I need to address? What will I have to do address them, how much will it cost? 6) What will consumers of my product think? How will they react? How can I find out in advance? 7) What liability questions are involved?
Hashisaka, A. E., Matches, J. R., Batters, Y., Hungate,
F.P., and Dong, F.M. 1990. Effects of gamma irradiation at -78°C on
microbial populations in dairy products. J. Food Sc. 55(5): 1284-1289.
The effect of low temperature (-78°C) gamma irradiation was investigated on microbial populations in selected dairy products to determine the irradiation dosage needed to product commercially sterile dairy products for immuno-suppressed patients. 40 kGy irradiation was sufficient to sterilize ice cream and frozen yogurt, but not mozzarella or Cheddar cheeses. Up to 8 weeks continued incubation of 40kGy irradiated products at 7°C or 35°C resulted in no resuscitative growth in ice cream or yogurt, but identifiable growth in the cheeses. The 12 D for B. cereus pre-inoculated into cheese and ice cream was 43 to 50 kGy.
Huhtanen, C. N. 1990. Gamma radiation inactivation
of enterococci. J. Food Protect. 53(4): 302-305.
Enterococci are streptococci that inhabit the intestinal tracts of mammals and possess the group D antigen. Among this group of group D streptococci that are routinely found in foods are Enterococcus faecium, and E. faecalis. The results of a previous study showed that the addition of a radiation resistant E. faecalis inhibited the formation of botulinal toxin in bacon. Radiation survival curves were determined for 7 strains of Enterococcus faecium, 10 strains of E. faecalis, and 8 strains of the proteolytic variety of E. faecalis. The D values (i.e., the doses giving 90% reduction of viable counts) ranged from 5.0 - 47 kGy for E. faecium strains, 3.5 - 21 kGy for the E. faecalis strains, and 3.0 - 4.5 kGy for the proteolytic variants of E. faecalis strains. The survival curves were linear for most strains but some exhibited non-linear trends. The results of this study indicate useful radiation resistant strains of group D streptococci which may find application in low-dose irradiated foods for preventing toxin formation by
Hwang, K. T., and Maeker, G. 1993. Determination 6-ketocholestanol
in Unirradiated and irradiated chicken meats. J. Am. Oil Chem. Soc. 70(8):
A method to detect 6-ketocholestanol in unirradiated and irradiated chicken meats was developed by means of chloroform-methanol-water extraction, adsorption chromatographic column separation and gas chromatography. This method is able to measure cholesterol oxidation products at levels that are must lower than those of previous methods. The new procedure was used to detect 6-ketocholestanol in fresh, unirradiated chicken and measured more than 97% of the test compound added to chicken below the ppm level. Irradiation of chicken meats to a dose of 10 kGy increased the concentration of this compound to about 4 times the level of unirradiated meats. The main purpose of the current study, to isolate and quantitate 6-ketocholestanol as a possible indicator of prior irradiation of chicken meats was achieved by the development of this method.
Institute of Food Technolgists' Expert Panel on Food Safety
and Nutrition. 1983. Radiation preservation of Foods. A scientific status
summary. Food Technol. 37(2): 55-60.
A summary of the status of food irradiation in 1983. Definition of terms. Uses of food irradiation. Wholesomeness of irradiated foods.
Jones, J. M. 1992. Chapter 12. Food irradiation. Food
Safety. St. Paul, MN., Eagan Press: 301-330.
Excellent review of food irradiation prior to 1992.
Josephson, E. S., Thomas, M.H., and Calhoun, W.K. 1979.
Nutritional aspects of food irradiation: An overview. J. Food Proc. Preserv.
When foods are exposed to ionizing radiation under conditions envisioned for commercial application, no significant impairment in the nutritional quality of protein, lipid and carbohydrate constituents was observed. Irradiation was no more destructive to vitamins than other food preservation methods. It was noted that there were small losses of Vitamin E and Thiamin. Protection of nutrients is improved by holding the food at low temperature during irradiation and by reducing or excluding free oxygen from the radiation milieu.
Karel, M. 1989. 1989. The future of irradiation applications
on earth and in space. Food Technol. 43(7): 95-97.
On earth, food irradiation will most likely be used in combination with other preservation techniques. In space, how irradiation will be used will depend on the length of the voyage.
Katzenstein, L. 1992. Food Irradiation: The story behind
the scare. American. Health(December): 61-68.
Details activities of consumer group, Food and Water based in Marshfield, Vt. that is leading a nation wide campaign to keep food irradiation from winning public acceptance. For example, this radio advertisement was heard by millions of Floridians in the summer of 1991: "What if you found out that those fresh fruits and vegetables everyone keeps telling you to eat more of might kill you? No joke.... Supermarkets have started selling radiation-exposed foods: spices, processed foods and soon, meats, fruits and vegetables.....Many scientists are saying irradiation makes foods unsafe, changes the molecular structure of food, destroys nutrients. And new studies show that ingesting radiation-exposed foods causes genetic damage, which can lead to cancer and birth defects....." This campaign plays on two consumer concerns: anxiety over food safety and mistrust of anything involving radiation. (Consumers relate this to Chernobyl or three mile island.) The scare tactics have paid off. So far, just one food irradiation plant has opened in the U.S. And aside from some scattered sales of irradiated produce, Food and Water has fulfilled its pledge: "We will stop radiation exposed food." The rest of the article deals with the history of irradiation of foods, its benefits, and its uses in countries of the world and the U.S. Other groups which look upon food irradiation with suspicion include Ralph Nader's Public Citizen Consortium and Michael Jacobsen's Center for Science in the Public Interest.
Kawamura, Y., Uchiyama, S., and Saito, Y. 1989. Improvement
of the half-embryo test for detection of gamma-irradiated grapefruit and
its application to irradiated oranges and lemons. J. Food Sc. 54(6): 1501-1504.
The application of ionizing radiation to foods stuff is permitted in several countries, and its use is increasing. Some countries require that irradiated foods be labeled, while in other countries irradiation is still prohibited. Therefore, a test is necessary to determine if foods have been irradiated. The test reported in this study can be used to assess if citrus fruits (oranges, lemons, and grapefruits) have been irradiated. Previously, a test, to identify irradiated grapefruit was based on the growth of half-embryos, consisting of one cotyledon and embryo axis, extracted from grapefruit seed. Shoots of the half-embryos treated with more than 0.15 kGy did not undergo elongation, where as shoots of non-irradiated or those with under 0.05 kGy elongate significantly by the 6th day of the test. This research showed that the test could be shortened to 3 or 4 days by optimizing growth temperature (35°C) and using gibberellin.
Lakritz, L., and Thayer, D.W. 1994. 1994. Effect of gamma
radiation of total tocopherols in fresh chicken breast muscle. Meat Science
Chicken breasts were irradiated in air with a Cesium 137 source at 0, 1, 3, 5.6 and 10 kGy at 0-2°C. The fresh muscle tissue was saponified and the total tocopherols were isolated and quantitated using normal phase high performance liquid chromatography with a fluorescence detector. Gamma irradiation of the chicken resulted in a decrease in alpha tocopherol with increasing dose. At 3 kGy and 2°C, the radiation level approved by the FDA to process poultry, there was a 6% reduction in alpha tocopherol level. No significant changes were observed for gamma tocopherol.
Lea, J. S., Dodd, N.J.F., and Swallow, A.J. 1988. A method
of testing for irradiation of poultry. Internat. J. Food Sci. Technol.
A method for the detection of irradiated poultry by ionizing radiation within the hard crystalline matrix of bone can be detected by the technique of electron spin resonance (ESR) spectroscopy. The ESR signal increases linearly with dose over the likely commercial range and is stable over the probable shelf-life under likely storage conditions. The lower limit of detection is equivalent to a radiation dose of 50 Gy. The test appears equally applicable to turkey, duck and goose. Poultry has been cleared for irradiation in 12 countries. (This includes the USSR, Netherlands and Canada.) "The British government has decided not to permit the process until controls can be devised"
Lee, P. R. 1994. 1994. Irradiation to prevent foodborne
illness. J. Am. Med. Assoc. 272(4): 261.
Very good review article by the Assistant Secretary for Health, U.S. Public Health Service. Points out importance of using irradiation to prevent foodborne illness. Foodborne illness is one of the largest preventable public health problems in the United States. Studies by the Centers for Disease control and prevention show that foodborne diseases caused by pathogenic bacteria, such as Salmonella, Campylobacter, Escherichia coli, and by Vibrio, Trichinella, tapeworms, and other parasites, cause an estimated 9000 deaths from 6.5 million to 81 million cases of diarrheal disease annually. Points out need for U.S. Public Health Service responsibility to use what is known to protect and improve the health of the public. Each modern food-processing advance--pasteurization, canning, freezing--produced criticism. Food radiation is not different.
Lester, G. E., and Wolfenbarger, D.A. 1990. Comparisons
of Cobalt-60 gamma irradiation dose rates on grapefruit flavedo tissue
and on Mexican fruit fly mortality. J. Food Protect. 533(4): 329-331.
Grapefruit grown in Mexico, Central America, and South America frequently are infested with larvae of the Mexican fruit fly Anastrepha loudness. To prevent entry of this insect into the United States, grapefruits must be quarantine and treated with ethylene dibromide. This study reported 20 grays/ 0.25, 0.5, 1.0, or 100 min. reduced adult emergence of Mexican fruit flies from larvae by >99%. Therefore, once a quarantine security treatment for the Mexican fruit fly is established, a low irradiation dose rate can be used to reduce adult emergence and should impart little damage to grapefruit peel tissue.
Loaharanu, P. 1989. International Trade in Irradiated
foods: Regional status and outlook. Food Technol. 43(7): 77-80.
Harmonizing national regulations regarding food irradiation will facilitate international trade. The upsurge in the interest in food irradiation by national authorities and industry may be attributable to: 1) increasing concern over foodborne diseases and uses of certain chemicals in food; 2) high post-harvest food losses from infestation, contamination, and microbial spoilage; and 3) stringent regulations related to quality and quarantine in international trade in food products. At present, 36 countries have provisions in their regulations allowing the use of irradiation of specific food items--either unconditionally or on a restricted basis.
Loaharanu, P. 1994. Status and prospects of food irradiation
Food Technol. 48(5): 124-131.
Where food irradiation has been approved and what it is being used for on a commercial basis around the world.
Maeker, G., and Jones, K.C. 1993. A-ring oxidation products from gamma-irradiation of cholesterol in liposomes. J. Am. Oil Chem. Soc. 70(3): 255-259.
Further research has been carried out to explore the potential identification of irradiated meat and poultry by determining the effect that gamma irradiation has on cholesterol. Gamma-irradiation of cholesterol in multilamellar vesicles (MLV) at 0°C-4°C causes oxidation of the A-ring. Two A-ring oxides formed in considerable amounts are cholest-4-en-3-one (10) and cholest-4-ene-3,6-dione (12) in addition to the usual B-ring oxides. Lesser amounts of cholest-4,6-dien-3-one (11) are also generated. Compounds 10 and 12 were detected and measured in cholesterol irradiated at less than 0.5 kGy in liposomes containing saturated and unsaturated phospholipids. Lesser amounts of 10 and 12, as well as lesser amounts of other cholesterol oxides were formed when a major constituent of the MLV was dilinolleoylphosphatidylcholine. Autoxidation of cholesterol in MLV also gave rise to small amount of 10, 11, and 12.
Marsden, J. L. 1994. Irradiation and food safety. Chicago,
IL., American Meat Institute.
Discusses benefits of irradiation of meats. AMI Position: American Meat Institute is actively involved in the investigation of viable pathogens preventing technologies which can be applied to the meat and poultry industry. Irradiation is one of those technologies and it is one that has garnered widespread support from governments and scientists worldwide. In AMI's view, reducing pathogens in the food supply and preventing foodborne illness will demand a multi-faceted, farm to table approach. While irradiation may be helpful, it alone will not solve public health problems related to foodborne pathogens.
Proctor, B. E., and Goldblith, S.A. 1951. Food processing
with ionizing radiation. Food Technol. 5: 376.
Research studies of food irradiation done in the late 40's and early 50's.
Pszczola, D. E. 1990. Food irradiation: Countering the
tactics and claims of opponents. Food Technol.. 44(6): 92-97.
A survey about food irradiation find the following facts to be true: 1) Irradiation has the potential to help solve the problem of salmonellosis and other foodborne diseases. 2) More than 40 years of research confirm the wholesomeness, safety for consumption and nutritional adequacy of irradiated foods. 3) Thirty-six countries have approved the process for more than 49 different foods and 20 countries are currently engages in commercial-scale irradiation of specific food items. 4) Astronauts, patients with suppressed immune systems who require sterilized diets, and study volunteers have consumed irradiated products without adverse effects. 5) The FDA has approved irradiation for certain uses: most recently (May 2, 1990) for controlling bacterial contamination in chicken, turkey and other fresh and frozen uncooked poultry. 6) Major health organizations, international committees of experts, and scientific societies have endorsed it. Opponents of food irradiation have charged that the process will be used to conceal food contamination, lower food quality standards, and increase risk to the public. To anti irradiation activists, this issue is both a political and psychological one. Labeling (FDA requires labeling if the entire product or major ingredient has been irradiated. Irradiated spices in foods are considered minor ingredients and do not require labeling.) Irradiation has the potential to solve certain problems that other methods cannot sufficiently address. These include. 1) Lessening the incidence of foodborne illness by reducing or eliminating pathogen contamination. 2) Using irradiation as alternative to chemical fumigants to control insects on fruits, vegetables, cereals, and nuts. 3) Irradiation can decrease losses of foods after harvest. 4) Irradiation can make available a large quantity and wider variety of foods to consumers. Article points out that supporters of food irradiation must educate food and health professionals (food scientists, home economists, dietitians, nutritionists and doctors), consumers and the media.
Roberts, T., and Murrell, K.D. 1993. Cost-benefit aspects
of food irradiation processing. In Proceedings of an International Symposium
of Cost-benefit. Aspects of Food Irradiation Processing, Aix-en-Provence:
International Atomic Energy Agency.: 51-75.
Fragmentary data indicate that various parasites cause human illnesses with medical costs and productivity and disability losses totaling billions of dollars annually. Food is an important vehicle for some of these parasitic diseases. In the United States, congenital toxoplasmosis is estimated to cost up to $5.3 x 109 annually of which sum perhaps half can be attributed to food sources. Irradiation of fresh pork could decrease cases of congenital toxoplasmosis. Similarly, other parasitic diseases could be reduced by irradiating beef, pork or fish. To determine whether irradiation is the most cost effective method of disease reduction, alternative control techniques need to be evaluated such as farm management strategies to reduce Toxoplasma gondii in hogs. Other parasites are discussed. These include: Cyticerci, Anisakindinae, Trichinella spiralis, and Giardia lamblia.
Schutz, H. G., Bruhn, C.M., and Diaz-Knauf, K.V. 1989.
Consumer attitudes toward irradiated foods: Effects of labeling and benefits
information. Paper No. 84. Annual Meeting of Int. Food Technologists, June
25-29., Chicago, IL.
Reported a nationwide study on the influence of label statements on the perception of quality, safety, and willingness to buy. The label statements used were "Irradiated to control microorganisms", "Irradiated for quarantine control, "Irradiated to extend shelf life", and "Irradiated to control spoilage." Consumers thought the products bearing the label "Irradiated to extend shelf life", and "Irradiated to control spoilage" would stay fresh longer. They also responded that a food with a label "Irradiated to control microorganisms" was an indication of higher quality than a non-irradiated food. People thought it would probably be safer and more expensive than the non-irradiated counterpart; about 50% said they would like to buy the product.
Skala, J. H., McGown, E.L., and Waring, P.P. 1987. 1987.
Wholesomeness of irradiated foods. J. Food Protect. 50(2): 150-160.
The history and applications of food irradiation are reviewed. The term wholesomeness when applied to food irradiation, embodies the concepts of microbiological and toxicological safety, and nutritional adequacy. The status of these areas of concern is reviewed. Nutritional studies have addressed the effects of irradiation on nutrient content and bioavailability, and evaluation of potential consequence of changes in either. Results of rat studies are presented in which we tested for the presence of anti-thiamin and antipyridoxine activity in radappertized chicken and beef. Test meats were analyzed for thiamin and pyrydoxine to establish a basis for incorporation into repletion diets. Thiamin levels in gamma- and electron-irradiated, and thermally processed (commercial canning) chicken were 74, 34, and 87% respectively, of the frozen meat reference; the levels in beef were 77, 56 and 79% Rat feeding studies were conducted. It was concluded that these irradiated meats pose no problem regarding vitamins B1 and B6, if part of a complete diet.
Stevenson, M. H. 1994. Identification of irradiated foods.
Food Technol. 48(5): 141-144.
Electron spin resonance spectroscopy and detection of 2-alkylcyclobutanones are two approaches available to identify foods that have been irradiated.
Thayer, D. W., Lachica, R.V., Huhtanen, C.N., and Wierbicki,
E. 1986. Use of irradiation to ensure the microbiological safety of processed
meats. Food Technol. 40(4): 159-162.
The use of ionizing (gamma) radiation can be used as an alternative to thermal processes for the preservation of food. This article reviews the research studies of the used of ionizing radiation to extend the safety of processed meats. Reports of meat products studied were: bacon, ham, frankfurters, corned beef and pork sausage, and beef, chicken and pork. Beef, chicken and pork were organoleptically acceptable after irradiation in vacuo at -30°C (+/-10°C). 12D doses for the process were 4.12, 4.27, and 4.37 Mrad for beef, chicken, and pork loin, respectively. With cured meats, sublethal radiation doses may actually increase the spoilage rate.
Thayer, D. W. 1987. Assessment of the wholesomeness of
irradiated food. pp. 236-241. In Fielden, E. M., J. F. Fowler, J. H. Hendry,
and D. Scott (eds.), Proceedings of the 8th International Congress of Radiation
Research. Taylor and Francis. London.
Abstract not prepared.
Thayer, D. W., J. P. Christopher, L. A. Campbell, D. C.
Ronning, R. R. Dahlgren, G. M. Thomson, and E. Wierbicki. 1987. Toxicology
studies of irradiated-sterilized chicken. J. Food Protect. 50:278-288.
Abstract not prepared.
Thayer, D. W. 1990. Food irradiated: Benefits and concerns.
J. Food Quality. 13: 147-169.
Abstract not prepared.
Thayer, D. W., J. B. Fox Jr., and L. Lakritz. 1991. Effects
of ionizing radiation of vitamins. IN Food Irradiation. S. Thorne, (ed.),
Elsevier Applied Science Publishers, London. pp. 285-325.
Abstract not prepared.
Thayer, D. W., and Boyd, G. 1992. Gamma ray processing
to destroy Staphylococcus aureus in mechanically deboned chicken
meat. J. Food Sci. 57(4): 848-851.
Gamma radiation doses of 0.26 kGy and 0.36 kGy, administered in vacuo at 0°C, destroyed 90% of log-phase and stationary-phase colony forming units (CFU) of Staphylococcus aureus ATCC 13565 (FDA 196E), respectively, in mechanically deboned chicken meat (MDCM). Samples inoculated with 103.9 CFU/g of S. aureus were treated with gamma radiation in vacuo at 0°C and then held for 20 hr at 35°C (abusive storage). Enterotoxin was not detected in irradiated MDCM. A predictive equation was developed for the response of S. aureus in MDCM to radiation dose and irradiation temperature.
Thayer, D. W., Boyd, G., and Jenkins, R.K. 1993. Low-dose
gamma irradiation and refrigerated storage in vacuo affect microbial flora
of fresh pork. J. Food Sci.. 58(4): 717-719.
Vacuum-packaged ground fresh pork samples absorbed gamma radiation doses of 0, 0.57, 3.76, 5.52, or 7.25 kGy at 2°C. Samples were analyzed after 1, 7, 14, 21, 28, or 35 days storage at 2°C for presence and number of aerobic and anaerobic mesophiles and endospore formers and aerobic psychrotrophs. Conventional plate counts did not detect surviving microflora in any sample that received an absorbed dose of 1.91 kGy or high, even after refrigerated storage for up to 35 days. The microflora in the control were predominantly Gram-positive for the first 21 days; however, Serratia predominated at 28 and 35 days. Staphylococcus, Micrococcus, and other yeast species predominated in samples that received 0.57 kGy.
Thayer, D. W. 1993. Irradiation for control of foodborne
pathogens on meat and poultry. Safeguarding the Food Supply through Irradiation
Processing Techniques, Orlando, Florida,. Bethesda, MD., Agriculture Research
Research from the USDA, Agricultural Research Service is reviewed which defines the effect of atmosphere and irradiation temperature on control of the foodborne pathogens Aeromonas, Listeria, Salmonella, and Staphylococcus. The results indicate that both the temperature and atmosphere during irradiation of meats is important and that these pathogens can be greatly reduced in population by radiation doses of 3 kGy or less.
Thayer, D. W. 1993. Extending shelf life of poultry and
red meat by irradiation processing. J. Food Protect. 56(10): 831-833, 846.
Research has demonstrated that ionizing radiation can inactivate parasites, eliminate or greatly reduce the populations of microbial pathogens, and extend the shelf life while preserving the desired nutritional and sensory properties of refrigerated poultry and red meat. Foodborne pathogens can be greatly reduced in population and sometimes completely eliminated from foods by low doses of ionizing radiation. The shelf life of poultry, pork, and beef can be significantly extended by treatment with ionizing radiation. Combination treatments with vacuum packaging or modified atmosphere packaging and ionizing radiation have produced better than predicted results. Additional research is needed on the combined processes.
Thayer, D. W., and Boyd, G. 1993. Elimination of Escherichia
coli O157:H7 in meats by gamma irradiation. Appl. Environ. Microbiol.
The aims of this study were to determine the sensitivity of Escherichia coli O157:H7 suspended in beef or mechanically deboned chicken meat (MDCM) to gamma irradiation and also to determine the influence of processing parameter such as atmosphere or temperature on that sensitivity. Undercooked and raw meat has been linked to outbreaks of hemorrhagic diarrhea due to the presence of E. coli O157:H7; therefore, treatment with ionizing radiation was investigated as a potential method for the elimination of this organism. Response-surface methods were used to study the effects of irradiation dose (0 to 2.0 kGy), temperature (-20°C to +20°C, and atmosphere (air and vacuum) on E. coli O157:H7 in mechanically deboned chicken meat. Differences in irradiation dose and temperature significantly affected the results. 90% of the viable E. coli in chicken meat was eliminated by doses of 0.27 kGy at +5°C and 0.42 kGy at -5°C. Small but significant differences in radiation resistance by E. coli were found when finely ground lean beef rather than chicken was the substrate. Unlike non-irradiated samples, no measurable verotoxin was found in finely ground lean beef which had been inoculated with 104.8 CFU E. coli O157:H7 per gram, irradiated at a minimum dose of 1.5 kGy, and temperature abused at 35°C for 20 h. Irradiation if an effective method to control this foodborne pathogen.
Thayer, D. W., Fox, J.B., and Lakritz, L. 1993. Chapter
23. Effects of ionizing radiation treatments on the microbiological, nutritional,
and structural quality of meats. Food Flavor and Safety. H. A. M. Spanier
Okai, and Tamura, M., Am. Chemical Society.: 294-302.
Treating fresh or frozen meats with ionizing radiation is an effective method to reduce or eliminate several of the foodborne human pathogens such as Salmonella, Campylobacter, Listeria, Trichinella, and Yersinia. It is possible to produce high quality, shelf stable commercially sterile meats. Irradiation dose, processing temperature, and packaging conditions strongly influence the results of irradiation treatments on both microbiological and nutritional quality of meat. These factors are especially important when irradiating fresh non-frozen meats. Radiation doses up to 3.0 kGy have little effect on the vitamin content, enzyme activity, and structure of refrigerated non-frozen chicken meat, but have very substantial effects on foodborne pathogens. Some vitamins, such as thiamin are very sensitive to ionizing radiation. Thiamin in pork is not significantly affected by the FDA-approved maximum radiation dose to control Trichinella, but at larger doses, it is significantly affected.
Thayer, D. W. 1994. Wholesomeness of irradiated foods.
Food Technol. 48(5): 132, 134 & 136.
Review of data and concerns raised during the approval process for irradiation of poultry indicates that properly processed irradiated foods are wholesome. Neither short nor multigenerational feeding studies have produced evidence of toxicological effects in mammals due to their ingestion of irradiated foods.
Thayer, D. W., Boyd, G., Fox, J.B., Lakritz, L., and Hampson,
J.W. 1994. Variations in radiation sensitivity of foodborne pathogens associated
with the suspending meat. J. Food Sc.
Longissimus dorsi from beef, pork, and lamb and lamb and turkey breast and leg meats were inoculated with Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp. and Staphylococcus aureus, and the gamma radiation resistance of the pathogens were determined under identical conditions. At a temperature of 5°C, the respective radiation D-value for the mixture of Escherichia coli O157:H7 and Listeria monocytogenes were not affected by the suspending meat. The D-value for a mixture of Salmonella spp. was significantly lower on pork than on beef, lamb, turkey breast, and turkey leg meats. The D-value for S. aureus was significantly lower on lamb and mechanically deboned chicken meat than on the other meats. All values were, nevertheless, within the ranges expected for these pathogens.
Thayer, D. W., Boyd, G., Fox, J.B., and Lakritz, L. 1995.
Effects of NaCl, sucrose, and water content on the survival of Salmonella
typhimurium on irradiated pork and chicken. J. Food Protect. 58 (4):
The effects of water content, activity, NaCl, and sucrose content on the survival of Salmonella typhimurium ATCC 14028 on irradiated mechanically deboned chicken meat (MDCM) and ground pork loin were investigated. The effects of NaCl and sucrose concentration were investigated by adding various amounts to MDCM or ground pork loin with NaCl solutions with various degrees of saturation. The effects of water content were investigated by rehydrating freeze-dried ground pork loin with different quantities of water. Inoculated samples were irradiated at 5°C in vacuo to doses up to 6.0 kGy. Highly significant effects (p<0.01) of water content, water activity and NaCl content, but not of sucrose content, on the survival of S. typhimurium were identified. The failure of sucrose to provide the same protection for S. typhimurium in meat against radiation argues against reduced water activity being a primary mechanism of protection. The results indicate that the survival of foodborne pathogens on irradiated meat with reduced water content or increased NaCl levels may be greater than expected.
Thayer, D. W., and Boyd, G. 1994. Control of enterotoxic
Bacillus cereus on poultry or red meats, and in beef gravy by gamma
irradiation. J. Food Protect. 57 (9): 758-764.
The gamma-radiation resistance of five enterotoxic and one emetic isolate of Bacillus cereus vegetative cells and endospores was tested in mechanically deboned chicken meat (MDCM) ground turkey breast, ground beef round, ground pork loin, and beef gravy. The D10 Values for B. cereus ATCC 33018 were 0.184, 0.431, and 2.56 kGy for logarithmic-phase cells, stationary-phase cells, and endospores at 5°C on MDCM, respectively. Neither the presence nor absence of air during irradiation significantly affected radiation resistance of vegetative cells or endospores of B. cereus ATCC 33018 when present on MDCM. Irradiation temperature (-20°C to +20°C) did affect the radiation resistance of stationary-phase vegetative cells and to a limited extent that of spores on MDCM. Impedance studies indicated that surviving vegetative cells and to a limited extent that of spore on MCDM. Impedance studies indicated that surviving vegetative cells were severely injured by radiation. A dose of 7.5 kGy at 5°C was required to eliminate a challenge of 4.6 x 103 B. cereus ATCC 33018 from temperature-abused MDCM (24 h at 30°C). The radiation resistance of a mixture of endospores of six strains to gamma radiation was 2.78 kGy in ground beef round, ground pork loin, and beef gravy, but 1.91 kGy in turkey and MDCM. The results indicate that irradiation of meat or poultry can provide significant protection from vegetative cells but not from endospores of B. cereus.
Thayer, D. W., E. S. Josephson, A. Brynjolfsson, and G.
G. Giddings. 1996. CAST Issue Paper Radiation Pasteurization of Food. No.
7. Council for Agricultural Science and Technology. Ames, Iowa. 10 pages.
Abstract not prepared.
The Gallup Organization. 1993. Consumer awareness, knowledge,
and acceptance of food irradiation. (Statistical report. No.). Chicago,
IL., American Meat Institute Foundation.
Gallup survey of consumer opinion regarding irradiated food. Example of questionnaire is also included with report. Report also includes results from a survey of hospital dieticians in the Atlanta, Georgia area.
Tinsley, P. W., and Maerker, G. 1993. Isolation and identification
of palmitoylphophocholinepropanediol from gamma-irradiated dipalmitoylphosphatidylcholine.
J. Am. Oil Chem. Soc. 70(8): 815-816.
1-Palmitoyl-3-phophocholinepropanediol was isolated from gamma irradiated aqueous suspensions of dipalmitoylphophatidylcholine. The product was positively identified by comparison of its high-performance liquid chromatography elution time and its mass spectra with the synthetic compound. Possible use as an indicator compound of irradiation.
Tinsley, P. W., and Maeker, G. 1993. Effect of low-dose
gamma-radiation on individual phospholipids in aqueous suspension. J. Am.
Oil Chem. Soc., 70(2): 187-191. 70(2): 187-191.
Acceptance and utilization of irradiation in food preservation varies greatly worldwide. Thus, fast and efficient analytical methods are needed to determine whether food has been irradiated. Because phospholipids play an important structural and functional role in all cellular membranes, a thorough examination of phospholipid radiolysis could yield an effective means for the detection of irradiated food. A series of individual phospholipids (phosphatidylcholines, phosphatidylethanolamines, phosphatidylserines, and phosphatidylglycerols) containing either saturated or unsaturated fatty acid chains was irradiated at 9.66 kGy and 0-4°C in aqueous suspension. The phospholipids were analyzed on a silica column with an evaporative light scattering detector. Phospholipid disappearance and production of two radiolytic products, phosphatidic acid and the lysophosphospholipid, after irradiation were quantitated from calibration curves of synthetic standards. Dipalmitoylphosphatidic acid and monopalmitoylphophatidylcholine from irradiated dipalmitoylphosphatidylcholine were identified by liquid secondary-ion mass spectrometry. However, it was concluded that since both of these compounds are endogenous in foods, analyzing for there presence cannot be used as an indication of irradiation processing.
Urbain, W. M. 1989. Food Irradiation: The past fifty years
as prologue to tomorrow. Food Technol. 43(7): 76-92.
Ionizing radiation was found to be lethal to living organisms very soon after its discovery prior to 1900. It was not until the 1940's that proper kinds of ionizing radiation became available. Cobalt 60 and Cesium 137, which in their radioactive decay emit gamma rays, became available. The research starting in 1943, soon became a large activity with both private and government programs in the U.S. Work on the process has since spread to other countries throughout the world. Irradiation can provide considerable advantages. These include: 1) Preserves food to varying extent as determined by the treatment. Food irradiation is particularly effective in controlling foodborne spoilage microorganisms. All organisms present in the food can be inactivated to secure long-term preservation or a fraction of them can be inactivated to secure limited extension of product life. Meats, seafood, fruits, vegetables, cereal grains, and legumes are some of the foods than can be preserved. 2) Decontaminates food of pathogenic bacterial, yeast, molds, and insects. This decontamination can improve the hygienic quality of the foods and prevent the potential health hazards. Meats and seafood can be decontaminated of bacteria and parasites; cereal grains, legumes, fruits, and dried fish of insect; spices and vegetable seasonings of bacteria and insects. 3) Controls maturation, senescence, and sprouting of fresh fruits and vegetables. 4) Alters chemical composition for quality improvement. The chemical composition of cereal grains and legumes can be altered so as to improve their quality. This is regulated by the dose, i.e., amount of radiation absorbed by the food. 5) Produces no toxic residues in foods. This is accomplished by limiting the energy level of the radiation employed and also be selecting the type of radiation. The lethal action of ionizing radiation on living organisms was traced to alteration of the DNA molecule. Products formed in foods by irradiation were identified and determined to be of no toxicological significance to the consumer of irradiated foods. 6) Maintains full nutritive value of foods. Studies have shown no changes in macronutrients and only insignificant ones in the micronutrients (vitamins). Irradiated foods were shown to be wholesome. 7) Maintains sensory quality. Knowledge of radiation chemistry has guided the development of means to prevent undesired sensory changes. An example of this W.H.O. 1987. Food irradiation No. 40). Irradiation is a physical method of processing foods which is comparable to methods such as heat treatment or freezing. It consists of exposing foods to gamma rays, e-rays or electrons over a limited period of time. X-rays and electrons are generated by appropriate machines, while gamma rays are generated by the radionuclided Cobalt-60 and Cesium-137. Cobalt-60 is not a waste product from the nuclear industry but is specifically manufactured for use in radiotherapy, sterilization of medical products and the irradiation of food. Caesium-137 is one of the fission products contained in used fuel rods. It must be extracted in reprocessing plants before it can be used as a radiation source. At present, almost all radiation facilities in the world use Cobalt-60 rather than Caesium-137. Advantages or the irradiation technique over conventional food processing methods are: 1) foods can be treated after packaging; 2) it permits the conservation of foods in the fresh state; 3) perishable foods can be kept longer without noticeable quality loss; 4) the cost of irradiation and the low energy requirements compare favorably with conventional food processing methods. Irradiation treatment up to the prescribed dose leave no residue; changes in nutritional value (i.e. loss of some vitamins) are comparable with those produced by other processes and during storage. Foods processed under prescribed conditions for irradiation do not in any way become radioactive - a fact which many people do not understand. Food irradiation is not a miracle process which can convert spoiled food into high quality food. It is equally true that not all foods are suitable for radiation treatment, just as not all foods are suitable for canning, freezing, drying, etc. Food irradiation has two main benefits to the health and well-being of man: 1) the destruction of certain foodborne pathogens, thus making the food safer, and 2) prolongation of the shelf-life of food by killing pests and delaying the deterioration process, thus increasing food supply. Before introducing this new technology, positive evidence and assurance had to be obtained that it would not have any hazardous side effects. The task of proving this was coordinated by the International Project in the Field of food Irradiation. Data generated by this Project were periodically reviewed by Joint FAO (Food and Agriculture Organization) /IAEA (International Atomic Energy Agency)/WHO (World Health Organization) Expert Committees which represent the collective views of a group of international top-level experts and not just the views of individuals or organizations. In 1980, the conclusion was reached that irradiation of any commodity up to an over all average dose of 10 KGy presented no toxicological hazard. This Committee also considered that irradiation of food up to this level introduced no special nutritional or microbiological problems, thus establishing the wholesomeness of irradiated food up to an overall average absorbed dose of 10 kGy. No new evidence suggests otherwise. In order to respond to questions still existing in 1980 concerning the microbiological safety of irradiated food, the Board of the International Committee of Food Microbiology and Hygiene (ICFMH) of the International Union of Microbiological Societies analyzed the scientific knowledge to date and concluded there was no cause for concern; there was no qualitative difference between the kind of mutation induced by ionizing radiation and that induced by other preservation processes, such as heat treatment or vacuum drying. Food irradiation was seen by the Board as an important addition to existing methods of controlling foodborne pathogens and did not, in their view, present any additional hazard to health.
WHO. 1994. Safety and Nutritional Adequacy of Irradiated
Food. World Health Organization. Geneva, Switzerland. (161 pages)
Abstract not prepared.
Wilkinson, V. M. and G. W. Gould. 1996. Food Irradiation.
A Reference Guide. Butterworth/Heinemann. Oxford. (177 pages)
Abstract not prepared.
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