Parts I, II, and III of this series provided a literature review and commentary on the history, technology, food safety, and food quality aspects relating to the use of ionizing radiation in fresh iceberg lettuce and spinach processing. To finish the analysis, a review of the literature on potential consumer and industry acceptance of food irradiation relative to its costs and benefits is presented. Two major and intertwined challenges might limit or delay the application of this processing method in the market place for fresh iceberg lettuce and spinach despite FDA’s approval: 1) consumer acceptance of the technology and 2) costs to the leafy green industry to implement the process. Given the gravity of the situation with outbreaks from fresh iceberg lettuce and spinach in recent years, it is imperative to examine carefully these challenges, and potential solutions including food irradiation.

Consumer Confidence and Acceptance

Consumer confidence in the lettuce and spinach industry

Fresh-cut (minimally processed) produce has grown to a $15 billion dollar per year industry in North America, and salad greens comprise a significant portion of that market, including iceberg lettuce and spinach (Palumbo et al, 2006). Likewise, a disproportionate number of the produce-related foodborne disease outbreaks have been linked to contaminated fresh-cut lettuce and spinach (Table, Part II). As a result, consumer confidence in this market has been shaken, which severely hurts the US economy, as well as the consumers who enjoy these products as fresh, healthy, and nutritious food sources.

For example, a survey conducted by the Food Marketing Institute of the US Grocery Shopper trends (2007) found that “safety concerns prompted 38 percent of consumers to stop purchasing certain foods in the past 12 months — up from 9 percent in 2006. Among those who stopped buying products, the items most often mentioned were spinach (71 percent), lettuce (16 percent), bagged salad (9 percent) and beef (8 percent). The survey was conducted in January 2007, when the outbreak linked to spinach was still in the news and illnesses associated with other foods were starting to make headlines.”

Based on these finding, one may ask: does food irradiation represent an opportunity to improve consumer confidence in the safety of fresh iceberg lettuce and spinach?

The answer would appear to be a resounding, “yes,” given the strong scientific evidence that irradiation is an effective and safe approach to reduce the levels of the most important foodborne pathogens in combination with other approaches such as GAPs and HACCP, as discussed in the earlier parts of this series. NASA has been irradiating astronauts’ food successfully since the 1970s, but acceptance and availability of the technology for approved foods such as ground beef and poultry in the civilian market place has been limited despite the benefits recognized by the scientific and medical communities. A review of consumer surveys provides insight into some of the complex reasons that this technology has not been widely adapted in the US and other parts of the world.

Historical perspective on consumer acceptance of food irradiation

Prior to FDA’s new rule for fresh iceberg lettuce and spinach, food irradiation at similar medium-level doses was approved in the US for numerous applications including control of foodborne pathogens in other fresh and processed foods. A large body of literature exists on the issue of consumer acceptance of food irradiation, especially for beef and poultry products. Notably, many of these consumer surveys took place 10-20 years ago, and similar studies on perceptions relating to the use of ionizing irradiation in fresh lettuce and spinach processing have not appeared in the literature as of the time of writing this review.

Dr. Christine Bruhn at the University of California, Davis published many of the pioneering studies on consumer acceptance, and recently made this comment about consumer acceptance of food irradiation in a series on the new FDA rule published by Jim Prevor’s Perishable Pundit (2008):

“My work and that of other researchers over the last 20 years has found some people are ready to buy irradiated product right now….This group of consumers represents maybe 10 percent of the population. At the other side of the spectrum, 10 percent of consumers are appalled by irradiation. They believe it makes the product less safe and less nutritious and wouldn’t touch it with a 10-foot pole. The majority of the population is in the middle. They don’t know very much about irradiation, or how it would benefit them.”

Clearly, the target audience for education (pros and cons) about food irradiation and FDA’s new rule concerning fresh iceberg lettuce and spinach, should be the 80 percent “in the middle.”

DeRuiter and Dwyer (2002) published a review article on consumer acceptance of irradiated food. Although slightly older, Sapp (1995) also provides an excellent review of the literature on consumer acceptance in the book, “Food Irradiation: A Sourcebook.” Some research highlights and selected original papers from these reviews and other sources are summarized below.

• Most consumers know little about food irradiation (American Meat Institute, 1993; Bruhn, 2001)
• A survey conducted at FoodNet sites in 1998-1999, indicated that the primary reason consumers would not buy irradiated foods (meat, poultry) was due to insufficient information about the risks and benefits; the survey also showed 50% of those asked were willing to buy irradiated meat and poultry and among those, 25% were willing to pay a premium price (Frenzen et al, 2000)
• Numerous studies have shown that consumer acceptance increases after they are given educational information about food irradiation, and many consumers have reported that they would prefer irradiated over non-irradiated meats after given science-based information (Bord and O’Connor 1989; Bruhn and Schutz, 1989; Fox et al, 1998; Resurreccion et al, 1995 )
• The use of audio and/or visual materials on food irradiation such pamphlets, slide shows and videos shifts consumers toward a positive attitude on food irradiation (Bruhn et al, 1986b; Hashim et al, 1995; Pohlman et al, 1994)
• Labeling is important to consumers, and strongly influences their acceptance of food irradiation; in one survey, 80% of US consumers indicated they would buy products with the approved Radura label and a statement: “irradiated to destroy harmful bacteria (Bruhn 2001)
• Consumers have expressed more concern about foodborne illness than irradiation “safety” (Bruhn et al, 1986)
• In a survey of 250 dieticians employed in health care facilities, the responses were surprisingly receptive to irradiation (Giamalva et al, 1998)
• Surveys indicate that military consumers, in particular, may be amendable to irradiated food (DeRuiter and Dwyer, 2002; Pohlman et al, 1994)
• Consumer confidence depends on making food clean first, and then using irradiation to make it even safer (DeRuiter and Dwyer, 2002)
• Consumers indicate they trust information most from health professionals (Bruhn 2001; American Meat Institute 1998); but, also trust in government and industry are the important factors affecting acceptance of irradiation (Bord and O’Connor, 1990)
• An interesting and innovative educational campaign was launched in Florida to promote food irradiation (Bruhn 2001; Hunter 2001), that engaged the state and local county health department and multiple media outlets. They used billboards with pictures of mothers and children to draw a comparison between pasteurized milk and irradiation. The billboard read:

Pasteurization, Safer Milk.
Irradiation, Safer Meat.

Additionally, the state health officer (a physician) made a statement directed at consumers and retailers (restaurants, grocery stores): “I hope you will purchase irradiated chicken and ground beef as they become available. This combination will afford your family maximum protection against foodborne illness.”

The role of the Internet in acceptance of food irradiation

It is worth noting, that since many of these studies were conducted more than a decade ago, the potential influence of the Internet, including anti-irradiation activist websites, has not been factored into the consumer acceptance equation. An informal survey on the web during this review showed a preponderance of mostly non-science groups against food irradiation, and a relative paucity of recent web-based information from scientists, industry, and government about the potential benefits. It is also difficult to predict how increased consumer demand for “organic” and “natural” foods will affect acceptance of food irradiation of fresh produce such as lettuce and spinach. Irradiation of organic food is currently prohibited. There is an urgent need to conduct new studies in today’s marketplace including assessments of consumer attitudes toward irradiation of leafy greens and other produce. Additionally, it would be useful to examine consumer demand in different types of markets (e.g., chain restaurants, institutional settings such hospitals, long-term care facilities, and prisons).

Economic Costs and Commercial Viability

Similar to the literature review on consumer acceptance, most of the papers that address economic costs and potential benefits (from reduced outbreaks and recalls) relating to food irradiation are outdated, and not specific for fresh lettuce, spinach or other leafy greens. Nevertheless, there are common themes that can be applied today when weighing the costs and benefits of radiation to control foodborne pathogens and spoilage organisms in fresh iceberg lettuce and spinach.

The human costs

The type of costs that accrue for individuals and society due to foodborne diseases and recalls include but are not limited to:

• Physician and emergency department visits
• Hospitalization
• Outpatient medication
• Productivity loss
• Long-term complications (e.g., HUS)
• Premature death
• Loss to industry from recalls and highly publicized outbreaks
• Loss of consumer confidence and market share
• Liability (lawsuits) and increased insurance premiums

As previously discussed in Part II, Tauxe (2001) analyzed the potential benefit of irradiated meat and poultry and estimated that 900,000 cases of infection, 8,500 hospitalizations, over 6,000 catastrophic illnesses, and 350 deaths could have been prevented each year. Similarly, Morrison et al (1992) conducted a cost:benefit analysis for irradiation of poultry products, and concluded that the savings from decreased foodborne illness would be greater than the small increase in cost passed on to consumers. Although similar studies have not been conducted for lettuce and spinach-related illnesses, it is reasonable to assume that irradiation would also result in reduced human illnesses and associated costs.

The facility costs

There is no debate concerning whether or not irradiation is technically feasible for fresh iceberg lettuce and spinach. The technology has been shown to be safe and effective (see Parts I, II, and III). The major disincentive for implementing food irradiation processing in the leafy greens industry relates to economic feasibility.

The fresh iceberg lettuce and spinach industry faces unique challenges with this technology. First, there is a geographic challenge. The majority of fresh iceberg lettuce and spinach is grown and shipped from the west coast (mostly the Salinas Valley, California). This region does not currently have a facility to accommodate radiation of fresh produce at the dose approved by the FDA for foodborne pathogen control; therefore, it is necessary to either 1) build stand-alone or in-line unit(s) in the major lettuce/spinach production region or 2) ship the packaged products to irradiation facilities in other distant parts of the country. There is potentially less financial risk in utilizing an offsite location given the uncertainty of consumer demand (see below); however, shipping to an out-of-state irradiation facility increases costs, and adds another layer in the distribution system where contamination could be introduced, especially if there is an accidental failure in temperature (refrigeration) control.

Second, it may be necessary still to optimize the conditions for ionizing radiation processing for specific facilities and product types/sizes (including packaging) to maximize the food safety benefits and minimize the potential negative effects on food quality such as off odors; this is a relatively simple problem to address once a facility is in place.

Several excellent reviews of the costs associated with irradiation facilities are available, but they are outdated (Cleland et al, 2001; Frenzen et al, 2001; Hayes, 1995; Kunstadt, 2001a; Kunstad, 2001b; Morrison et al, 1992; Morrison, 1989).

There are three major components that factor into costs for industry (and that may be passed on to consumers):

• Capitol costs (hardware and land/property)
• Annual operating costs (type of product and radiation source/dose, personnel maintenance, tax/insurance, regulatory requirements)
• Annual throughputs

Cleland et al (2001) summarize the critical importance of annual throughput: “total cost per unit of product decreases as the throughput rate increases because the fixed costs (e.g., capitol amortization, utilities, maintenance) are then spread over a larger market of units.” In other words, the financial success (economic feasibility) of building an irradiation facility is closely associated with the demand for the product.

Thus, the uncertainty of the market place with regard to the number of consumers (including retailers) that will purchase fresh iceberg lettuce and spinach treated with radiation for food safety and quality is perhaps the greatest challenge in implementing FDA’s new rule.

Consumer Willingness to Pay

Although the actual number of potential customers remains unclear for irradiated fresh iceberg lettuce and spinach, numerous surveys have indicated that once consumers are educated about the food safety benefits of the process, most are willing to pay an increased price (Bruhn 2001; Frenzen et al, 2001; Hayes, 1995; Sapp 1995). Furthermore, published studies indicate that the increased cost per pound for meat and poultry products amounts to only a few cents. Although current numbers are not available in the literature for lettuce/spinach, Sadex Corporation estimated the increased cost for food irradiation at the medium dose level would be approximately 10 to 20 cents per pound using e-beam technology (personal communication). This seems like a small price to pay for increasing food safety, but as reviewed exhaustively in this series, many complex scientific, social, economic, and policy factors influence the decisions surrounding acceptance and use of food irradiation.

In the final part of this series (Part V), the pros and cons of FDA’s new rule will be summarized, and the potential “next steps for action” presented.


1. Altekruse, S. F., S. Yang, B. B. Timbo, and F. J. Angulo. 1999. A multi-state survey of consumer food-handling and food-consumption practices. Am J Prevent Med. 16:216-21.
2. American Meat Institute. 1993. Consumer awareness, knowledge and acceptance of food irradiation. Gallop Organization: Arlington, VA, USA.
3. Anonymous. 2008. Irradiation in the production, processing and handling of food. Final rule. Fed Regist. 73:49593-603.
4. Anonymous. Irradiation and consumer acceptance. Published by Jim Prevor’s Perishable Pundit. Available at:
5. Bord, R. J. 1991. Consumer acceptance of irradiation food in the United States. In: Food Irradiation, S. Thorne (ed). London: Elsevier Applied Science. p. 61-86.
6. Bord, R. J. and R. E. O’Connor. 1989. Who wants irradiated food? Untangling complex public opinion. Food Technol. 43:87-90.
7. Bord, R. J. and R. E. O’Conner. 1990. Risk communication, knowledge, and attitudes: explaining reactions to a technology perceived as risky. Risk Anal. 10:499-506.
8. Bruhn, C. M., H. G. Schutz, and R. Sommer. 1986a. Attitude change toward food irradiation among conventional and alternative consumers. Food Technol. 40:86-91.
9. Bruhn, C. M., R. Sommer, and H. G. Schutz. 1986b. Effect of an educational pamphlet and posters on attitude toward food irradiation. J Ind Irrad and Technol. 4:1.
10. Bruhn, C. M., H. G. Schutz, and R. Sommer. 1987. Food irradiation and consumer values. Ecol Food Nutr. 21:219-35.
11. Bruhn, C. M. and H. G. Schutz. 1989. Consumer awareness and outlook for acceptance of food irradiation. Food Technol. 43:93-7.
12. Bruhn, C. M. 1995. Consumer attitudes and market response to irradiated food. J Food Protect. 58:157-81.
13. Bruhn, C. M. 2001. United States consumer choice of irradiated food. In: Irradiation for Food Safety and Quality. Loaharanu P. and P. Thomas (eds). Technolmic Publishing Company, Inc., Lancaster, PA. p. 169-73.
14. Cleland, M. R., A. S. Herer, and A. Cokragan. 2001. Economics of machine sources for irradiation of food. In: Irradiation for Food Safety and Quality. Loaharanu P. and P. Thomas (eds). Technolmic Publishing Company, Inc., Lancaster, PA. p. 158-68.
15. DeRuiter, F. E. and J. Dwyer. 2002. Consumer acceptance of irradiated foods: dawn of a new era? Food Serv Technol. 2:47-58.
16. Food Marketing Institute. 2007. FMI Consumer Trends 2007: Confidence in Food Safety Down, Energy Costs Changing How People Shop. Available at:
17. Fox, J. A. and D. G. Olson. 1998. Market trials of irradiated chicken. Radiat Phys Chem. 52:63-6.
18. Frenzen, P.D., A. Majchrowicz, J. C. Buzby, B. Imhoff, and FoodNet Working Group. 2001. Consumer acceptance of irradiated meat and poultry products in the United States. J Food Protect. 64:2020-6.
19. Giamalva, J. N., M. Redfern, and W. C. Bailey. 1998. Dietitians employed by health care facilities preferred a HACCP system over irradiation or chemical rinses for reducing risk of foodborne disease. J Am Diet Assoc. 98:885-8.
20. Hashim, I. B., A. V. A. Resurreccion, and K. H. McWatters. 1995. Consumer acceptance of irradiated poultry. Poultry Sci. 74:1287-94.
21. Hayes, D. J. 1995. The economics of marketing irradiated foods. Microbiology of irradiated foods. In: Food Irradiation: A sourcebook. E. A. Murano (ed). Iowa State University Press, Ames, Iowa. p. 111-26.
22. Hunter, C. 2001. Florida: a case study in marketing irradiated poultry. Microbiology of irradiated foods. In: Irradiation for Food Safety and Quality. Loaharanu P. and P. Thomas (eds). Technolmic Publishing Company, Inc., Lancaster, PA. p. 174- 7.
23. Kunstadt, P. 2001a. Economic and technical considerations in food irradiation. In: Food Irradiation: Principles and Applications. Molins, R. (ed). John Wiley & Sons, New York, NY. p. 415-42.
24. Kunstadt, P. 2001b. Economics of food irradiation. In: Irradiation for Food Safety and Quality. Loaharanu P. and P. Thomas (eds). Technolmic Publishing Company, Inc., Lancaster, PA. p. 129-57.
25. Morrison, R. M., T. Roberts, and L. Witucki. 1992. Irradiation of US poultry – benefits, costs, and export potential. Food Rev. 15:16-21.
26. Morrison, R. M. 1989. An economic analysis of electron accelerators and Cobalt-60 for irradiating food. USDA ERS Technical Bulletin #1762, Washington, DC.
27. Osterholm, M. T., and A. P. Norgan. 2004. The role of irradiation in food safety. N Engl J Med. 350:1898-901.
28. Palumbo, M.S., J. R. Gorny, D. E. Gombas, L. R. Beuchat, C. M. Bruhn, B. Cassens, P. Delaquis, J. M. Farber, L. J. Harris, K. Ito, M. T. Osterholm, M. Smith, and K. Ml J. Swanson. 2007. Recommendations for handling fresh-cut leafy green salads by consumers and retail foodservice operators. Food Protect Trends. 27:892-8.
29. Pohlman, A., O. Wood, and A. Mason. 1994. Influence of audiovisuals and food samples on consumer acceptance of food irradiation. Food Tech. 48:46.
30. Resurreccion, A. V. A., F. C. F. Galvez, S. M. Fletcher, and S. K. Misra. 1995. Consumer attitudes toward irradiated food, results of a new study. J Food Protect. 85:193-6.
31. Sapp, S. G. 1995. Consumer acceptance of irradiated foods. Microbiology of irradiated foods. In: Food Irradiation: A sourcebook. E. A. Murano (ed). Iowa State University Press, Ames, Iowa. p. 89-110.
32. Tauxe, R. V. 2001. Food safety and irradiation: protecting the public from foodborne infections. Emerg Infect Dis. 7:516-21.