E. coli and Irradiation
Would irradiation have prevented the recent outbreaks?

18 Dec 2006 in Regulatory Science, Regulatory Policy

Last fall's E. coli O157:H7 outbreak in spinach has now been followed by an outbreak in lettuce used by certain fast food enterprises. Today's Wall Street Journal includes an editorial criticizing "E. Coli's Enablers," by which they mean activists who oppose irradiation.

Would irradiation of produce intended to be consumed raw have prevented these outbreaks?

The Journal editorial board quotes scientists who say the answer is "yes."

Says Michael Osterholm, director of the Center for Infectious Disease Research at the University of Minnesota: "If even 50% of meat and poultry consumed in the United States were irradiated, the potential impact on foodborne disease would be a reduction in 900,000 cases, and 350 deaths." A 2005 CDC assessment agrees: "Food irradiation is a logical next step to reducing the burden of food borne diseases in the United States."

We asked several leading health scientists whether food irradiation could have prevented the E. coli outbreak at Taco Bell restaurants. "Almost certainly, yes," says Dennis Olson, who runs a research programs on food irradiation at Iowa State University. A recent study by the USDA's Agriculture Research Service confirms that "most of the fresh-cut (minimally processed) fruits and vegetables can tolerate a radiation of 1.0 kGy, a dose that potentially inactivates 99.999% of E. coli."

Iowa State's Olson has published extensively on irradiation. The Food Safety Consortium includes dozen of researchers at ISU and lists affiliations with Kansas State University, the University of Arkansas, and Western Washington University. ISU has a food safety web page devoted to irradiation.

Osterholm wears other hats as well. Until October 2006 he was associate director of the Department of Homeland Security's National Center for Food Protection and Defense, a university-based research consortium. He is a member of the National Academies' Institute of Medicine.

In 2004 Osterholm published an editorial commentary in Clinical Infectious Diseases on the subject of E coli O157:H7 and irradiation. Among other things, Osterholm says multiple previous regulatory efforts have failed — including the Hazard Analysis and Critical Control Points (HACCP) system that now dominates food safety regulation:

Recent analysis of the FoodNet data of 1996–2002 found that the incidence of E. coli O157:H7 infection did not significantly change at the FoodNet sites, despite implementation of several major control measures, including initiation of the pathogen reduction/hazard analysis critical point systems regulations for meat and poultry slaughterhouses and processing plants sponsored by the US Department of Agriculture (USDA) Food Safety Inspection Service. (p. 8)

Federal regulatory agencies, most notably USDA's Food Safety Inspection Service, promised that HACCP would work. We have previously shown that these claims were unsupported when they were made and that regulatory failure was easily predicted.

One of the lessons Osterholm draws from this experience is that "there will be only limited gains in reducing the incidence of meat- and poultry-related foodborne illnesses until the implementation of food irradiation becomes standard." He also says that outbreak investigations such as those initiated by CDC after the spinach (and now lettuce) outbreaks "have little real-time public health impact" (p. 8). He proceeds to cite statistics similar to those in the Journal editorial for the public health benefits of irradiation, which are readily accessible on the CDC web site.

With risks of this magnitude, and extensive support from government agencies, scientific organizations and food industry trade associations, why is irradiation so rarely employed? The Journal attributes this to opposition by Public Citizen, Consumers Union (publisher of Consumer Reports), and other activist groups. Public Citizen has challenged the credibility of academic scientists who support irradiation, including both Iowa State's Olson and Minnesota's Osterholm (here and here).

Public Citizen has a longstanding track record opposing irradiation, including:

• Opposition to changes to international standards that would expand the use of irradiation
• Opposition to the irradiation of tropical fruits
• Opposition to rules permitting the irradiation of imported fruits and vegetables
• Opposition to rules permitting the irradiation of oysters susceptible to Vibrio parahaemolyticus
• Opposition to Texas' decision to irradiate beef products served in schools and USDA's plan to encourage irradiation of ground beef served through its school lunch program

Public Citizen has denounced Giant Foods and Wal-Mart for selling irradiated meat, and endorsed some of Consumers Union's conclusions from a Consumer Reports' study whose purpose was to show that claims about the pathogen loads in irradiated meat were false. But the Consumers Union non-peer reviewed study implicitly supported these claims. Quoting from CU's press release:

There is no reason to buy irradiated meat if you cook meat thoroughly because irradiation actually destroys fewer bacteria than proper cooking does (emphasis added).

Later CU qualified this statement by acknowledging the problem of cross-contamination, but in CU's view this problem is best addressed in other ways. CU acknowledges (without attribution) Osterholm's benefit estimates, then attributes to CDC (without citation) the claim that "20 percent of such outbreaks are caused simply by commercial food preparers' poor hygiene." We've not been able to identify the source for this claim, and if true it is not obvious how CU would prefer that it be addressed.

CU's argument against irradiation appears to be based on the fact that it isn't perfect:

An advantage of irradiated meat is that it generally has lower bacteria levels than regular meat. Therefore, it may reduce--but not eliminate--the risk of foodborne illness if your meat is undercooked (emphasis added).

Similarly:

Bacteria levels in the irradiated, uncooked ground beef and skinless chicken tenders were generally much lower than levels in the non-irradiated meat. But the irradiated meat still contained some bacteria.

We have not reviewed the CU study itself. Minnesota's Osterholm published a letter to the editor of Consumer Reports challenging its research methods, results, and ethical practices..

CU's solution to the problem of pathogens appears to be a combination of perfection in kitchen hygiene (irradiation has "no real benefit for the careful cook") and intensified government regulation ("Consumers Union ... believes that the best way to improve meat quality is to clean up the food supply chain and strengthen USDA authority over meat safety").

Like Public Citizen, Consumers Union opposes irradiation even though it knows that it is effective and that its use will save lives. CU insists that irradiated food be labeled so that its allied consumers can protest its use.

Economist Randall Lutter wrote in 2000 that "Congress is partly responsible for delays in bringing food irradiation to the market. "

The Federal Food, Drug and Cosmetic Act defines sources of irradiation used to treat food as "food additives" and prohibits the use of food additives without an explicit determination of their safety. That definition delays the marketing of irradiated foods. In effect the Act directs FDA to assess the wrong question--whether irradiation is safe--rather than whether irradiated foods would reduce risks to public health, taking into account both the reduced incidence of food-borne illness and any loss of safety from increased irradiation.

He also blamed federal regulatory agencies for delays:

The regulatory agencies have also delayed the benefits of food irradiation by creating a redundant and complicated two-step approval process. The first step is a determination by the FDA that food irradiation, at particular doses, is safe for particular uses. The second step is a determination by the USDA that the use of irradiation

• is in compliance with applicable FDA requirements,
• does not render the product adulterated or misbranded or otherwise out of compliance with the requirements of the Federal Meat Inspection Act,
• is functional and suitable for the product, and
• is permitted only at the lowest level necessary to accomplish the stated technical effect as determined in specific cases.

That two-step process, while arguably sensible for additives that do not improve public health, substantially delays delivery of the benefits of food irradiation to consumers. The FDA approved irradiation of meat three years after receiving a petition; however, the USDA, which must also approve, took two more years to issue its own rule. In their recent rulemakings about meat irradiation, the agencies do not cite any recent scientific discoveries confirming the safety of irradiation. Instead, they cite safety evidence from twenty years ago.

Lutter, who is now FDA's Associate Commissioner for Policy and Planning, said that activist opposition has played a significant role in delaying these public health benefits:

The slow pace of government approval of irradiation has causes more complex than bureaucratic inertia and lack of interagency leadership. Cautionary or critical positions taken by several public interest groups play a role. Food and Water, a stridently anti-irradiation group, has paid for ads and organized phone and letter-writing campaigns against food irradiation. Consumers Union, the publisher of Consumer Reports, is neutral on the subject. Other influential groups, including Center for Science in the Public Interest, National Consumers League, and Consumer Federation of America, take a slightly more supportive stand, but still manage to impede improvements in public health by advocating conspicuous labeling and even increased testing of irradiated foods. Such views, because they are presented by "public interest" groups, can deter agencies that seek to regulate by consensus from implementing regulatory changes that would promote public health, unless there is strong political leadership.

It would be ironic if irradiation conflicted with the agendas of activist organizations and federal regulatory agencies precisely because it works. For activists, a successful technological solution renders future activism on the subject superfluous. For regulatory agencies, success would undermine the vast regulatory apparatus that Osterholm and CDC say has failed but which provides FDA and USDA significant employment and continued regulatory authority.

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Would irradiation have prevented the recent outbreaks?

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