Tuesday, December 12, 2006

How a fear appeals-based strategy used in the E. Coli outbreak in fresh spinach may contribute to negative effects on public health–Christine Lee

According to the Centers for Disease Control and Prevention (CDC), approximately 76 million cases of foodborne illnesses occur each year in the United States, accounting for substantial rates of morbidity and between 4000 to 5000 annual deaths (1). The monetary burden of foodborne illnesses has been estimated to be as high as $23 billion annually in addition to the costs associated with decreased productivity, product recalls, increased plant inspections, and enduring distrust of foods that have been implicated in an outbreak (2,3). According to data collected from 1996 to 2002 through the CDC’s FoodNet surveillance system, a decrease in the incidence of certain bacterial foodborne illnesses is occurring (4). However, this decline does not include enterohemorrhagic Escherichia coli (EHEC), serotype O157:H7, which has been the subject of the recent, much-publicized outbreak in fresh spinach. This suggests that increased efforts should be placed on determining why current strategies for reducing incidence have not been effective.

Background Information
As of early October 2006, 199 cases were reported to the CDC from 26 states in the recent outbreak of E. coli 0157:H7 in fresh spinach. 31% of the cases reported that onset of illness occurred between August 30th and September 1st. Certain serotypes of EHEC (including O157:H7) produce a Shiga-like toxin. Within one to ten days after ingestion of these bacteria, abdominal cramping and acute, bloody diarrhea often result. In healthy adults, symptoms typically resolve themselves within five to ten days. However, infection can become complicated by a type of kidney failure called hemolytic uremic syndrome (HUS), to which children are especially vulnerable (4). Approximately half of the reported cases were hospitalized and 13% (31 cases) developed HUS. In addition, three deaths have been confirmed, two in elderly women and the third in a two-year old child (5). The Food and Drug Administration (FDA) recently announced that all of the reported cases have been traced back to spinach processed by Natural Selection Foods, Inc. (commonly known by their flagship brand of bagged, organic salads, Earthbound Farm), headquartered in California’s Central Valley. Although the exact source of contamination is still undetermined, Natural Selection and four other companies issued recalls of all spinach products in mid-September (6).
In the United States, regulation of food safety involves a complicated division of responsibilities between many different agencies. Certain foodborne illnesses, including those caused by EHEC, require reporting to the CDC from the local level. Investigation of this outbreak has been primarily conducted through the joint efforts of the FDA, the CDC, the United States Department of Agriculture (USDA), and the State of California. In addition, many non-profit organizations and private businesses such as law firms specializing in food poisoning have also been actively involved (7).

Use of a communications strategy based on fear appeals
The communications strategy employed by the public health establishment in the aftermath of this outbreak is based on fear appeals (sometimes referred to as health threat communications). The Fear Appeals Theory is often employed in health education and uses fear as a motivator for individuals to make a positive behavior change (8,9). In this case, the behavior change is the discontinuation of spinach consumption. Consumer advice offered by CDC in its “outbreak updates” commands an official, foreboding tone that has sufficiently convinced many people that spinach consumption is unsafe. “Consumers should not eat, retailers should not sell, and restaurants should not serve spinach implicated in the E. coli O157:H7 outbreak” (5). The theory rests on the presumption that the individual will make the behavior change in order to control the “danger” or “health threat.” Furthermore, the level of effectiveness is at least partially dependent on the perceived significance of the danger and severity of emotional arousal (10). Virtually all media coverage of the outbreak has been highly emotional. Detailed, hear-wrenching accounts of parents grieving over dead or hospitalized children have been the norm, as well as a steadily increasing update on the number of reported cases nationwide (11,12).
The use of this strategy has most likely contributed to the curtailment of additional cases occurring in this outbreak due to its effectiveness in discontinuing the consumption of spinach. Maslow’s Hierarchy of Needs Model can be applied to help understand the reaction to this outbreak. Amongst the five levels of needs presented by the model, lower-level needs must be satisfied before attending to higher-level needs. Lower-level needs consist of biological and physical necessities including food, water, and shelter, as well as safety needs, such as protection and security (13). Therefore, food safety concerns may be considered both a lower and higher-level need. However, both needs (food and safety) would be satisfied by substituting the consumption of spinach with another food that is considered “safe.”
The positive effects resulting from application of this theory may only be short-term. The use of fear as a motivating force does not engender trust and confidence in the population. In the case of E. coli and spinach, confusion and paranoia have emerged and may result in long-term negative effects on public health (11,12,14). These may include a decrease in vegetable consumption and a sustained level of consumer distrust, potentially creating a scenario that may be difficult to remedy.

Resulting confusion and paranoia
The fear appeals-based communications strategy effectively influenced many people into avoiding the consumption of spinach. However, appropriate behavior for consumers was unclear throughout the outbreak, resulting in confusion and paranoia. CDC updates did not provide suggestions for spinach substitutes with similar nutritional content. Nor did they emphasize the facts that other vegetables were safe to consume and the importance of a healthy diet including continued consumption of vegetables. The fact that the route of contamination has yet to be identified adds to the existing confusion (6). The point at which spinach should be considered “safe” was unclear. In addition, instructions on safe spinach preparation were not practical. For example, the CDC advised consumers that E. coli bacteria could be killed by cooking it at 160° Fahrenheit for 15 seconds. They also mentioned that “if spinach is cooked in a frying pan, and all parts do not reach 160° Fahrenheit, all bacteria may not be killed” (4). Assuming the average home cook owns an accurate thermometer, what is the proper way to take the temperature of spinach cooked in a frying pan? Communication should have been made clearer to avoid confusion and paranoia. For example, the CDC could have recommended cooking spinach submerged in boiling water (water boils at 212° Fahrenheit) for a minimum of 15 seconds in order to eradicate E. coli.
According to the Health Belief Model (HBM), the intention of taking a behavior is influenced by four things: perceived level of susceptibility, perceived level of severity, belief that the behavior change will incur beneficial results, and the absence of barriers to adopting the behavior change (15). Therefore, the consumer is left to weigh the level of perceived risk against the perceived benefits. In this case, it is quite easy to see how all of the factors have been satisfied. The fear appeals-based communications strategy as well as media coverage of the outbreak was enough to convince an individual to believe him/herself to be susceptible to illness from continued consumption of spinach. Additional considerations, such as having children or knowing someone who has been personally affected by the outbreak, may have prompted a heightened sense of susceptibility and severity. The individual must also believe that the discontinuing spinach consumption would be beneficial, resulting in the avoidance of disease.
Observing others (or vicarious experience) is thought to influence behavior, as put forth by the Social Learning Theory (15,16). This model must be slightly modified in the case of young children, for whom the responsibility of decision-making lies with the parents. In light of young children’s higher likelihood of serious illness from infection, parents may be one segment of the population that has placed much weight on risk elimination in order to protect their families. “Some families still wait by bedsides, wondering what foods they could ever again feel safe giving their children, what the government or the spinach industry could have done to protect them…” (11).

Possible long-term negative health effects on public health
If confusion and paranoia persist in consumers, long-term negative effects on public health may include a decrease in vegetable consumption and a sustained level of consumer distrust. The Krauses, whose 9-year old son fell seriously ill with HUS after consuming a spinach salad, these negative effects are all too apparent. In the hospital cafeteria, the family could only bring themselves to eat peanut butter and jelly sandwiches because all of the other food options scared them. Mr. Krause sadly stated, “…you think you’re feeding your child a great, healthy meal. But… I was poisoning him” (11). Mrs. Krause also expressed “anger and paranoia and fear for others- for the safety of food we get that’s supposed to be monitored. I don’t know what to trust. Should we grow it all ourselves?” (11). Similarly, Gwyn Wellborn, an adult victim of serious illness from spinach consumption, expressed that she would not consider eating spinach again “in a million years” (11).
It is clear that Wellborn and the Krauses have developed a deep-seeded mistrust regarding the safety of their food and are not likely to resume consumption of spinach anytime soon. This is in spite of existing evidence extolling the benefits of a diet high in vegetables (18,19). According to the Theory of Self-Efficacy, a behavior can be adopted only if the individual believes that he/she has the ability to accomplish it (20). To apply this model, the behavior in question is continued consumption of spinach. To clarify, if someone does not believe he/she can consume spinach without becoming ill, that behavior is not likely to be adopted. In contrast, the maintenance of health by discontinuing spinach consumption is arguably an easier or more feasible alternative which would result in the same outcome: avoidance of disease.
Depending on an individual’s level of knowledge, this reasoning may be extrapolated to other vegetables. “It does not take a great leap of the imagination to conclude that whatever has caused the spinach contamination could equally affect other grown-in-the-ground vegetables” (14). In fact, the FDA has admitted to a long history of E.coli 0157:H7 outbreaks in leafy greens produced in the central California region (6). There may be some individuals who believe in an inherent risk of becoming ill from consumption of any vegetable, especially uncooked. For such an individual, the perceived risk outweighs the perceived health benefits associated with continued consumption. This reasoning may be heightened if a healthy diet is not a high-level priority for that individual. For those individuals, this outbreak may serve as a convenient excuse to avoid their recommended daily intake of vegetables (14).

Emergence of a Heath Disparity
Discontinuation of spinach consumption was indeed the overriding reaction in the general population. Largely due to the recall instituted by Natural Selection, who normally distribute their products to three quarters of American supermarkets, spinach was conspicuously absent from supermarket displays and many restaurant menus across the country by late September (21). Individuals who were well-educated about the outbreak and understand the importance of vegetable consumption were more likely to seek other alternatives to discontinuation of spinach consumption. This may be partly explained by circumstances in which a personal level of risk was able to be differentiated from a generalized risk to the population. To elaborate, if an individual knows the source of contamination for this outbreak originated from lettuce grown in California, he/she would also understand that consuming spinach grown locally in Massachusetts poses little risk of being contaminated by the implicated strain of pathogen. Similarly, if this segment of the population was unsuccessful in sourcing locally-grown, low-risk spinach at farmers markets or gourmet food stores such as Whole Foods, they may be more likely to replace the consumption of spinach with other comparable vegetables, such as Swiss chard or kale.
With this reasoning, it is possible that a health disparity may emerge as a result of this outbreak: namely, a decrease in vegetable consumption in certain segments of the population. The same alternatives may not be available for the entire population for various reasons. Lower socioeconomic status (SES), lack of time, cost, access, or convenience, or even sustained mistrust of the government could serve as barriers to adoption of a positive behavior (22). In vulnerable segments of the population, we are more likely to see a long-term decrease in overall vegetable consumption. Ironically, the risk factors associated with the likelihood of decreased vegetable consumption may be the same as those associated with the increased likelihood of obesity and other diet-related diseases (23,24,25). This implies that the same population most often targeted for diet-related health interventions may also be at highest risk of decreased vegetable consumption as a result of this outbreak. This is also an argument for more targeted food safety education campaigns. Otherwise, important food safety information may run the risk of “preaching to the choir,” the segment of the population that already possesses a high level of knowledge about the subject.

Some critics have denounced the modern, “agro-industrial” food production system as the real culprit behind the E. coli outbreak (26). A long history of E. coli outbreaks in leafy greens grown in California’s Central Valley implies that centralized production of large quantities of an identical product has contributed to the creation of a favorable environment for certain pathogens (6). Nationwide distribution has exacerbated the presence of this outbreak across state lines, thereby increasing the difficulty of tracing back to the source of contamination (26).
If this criticism taken to be true, the next question must ask what changes are being made to prevent a similar incident from occurring? Perhaps a more active voice on food policy issues may have prevented this. As a public health community, it is imperative that economic decisions do not take precedence over public health. In this case, irrigation water used on the spinach fields was suspected to be contaminated with manure from nearby beef cattle operations. Logically, it follows that farm animals should be kept separate from food crops that are typically eaten raw. However, one must consider whether proposed “solutions” are actually short-term technological fixes that could result in additional problems in the future (26).
The creation of one unified, national food-safety agency has been proposed to streamline the coordination and communication that is currently required between multiple governmental agencies (primarily CDC, FDA, and USDA). This may aid in the prevention of future outbreaks because it would also allow the respective agencies to concentrate on a narrowed scope of responsibilities. It goes without saying that the ability of any agency to perform its duties effectively is highly dependent on the level of funding allocated to them. Although the creation of one food-safety agency does not appear to be imminent for the time being, efforts are being made to improve the level of surveillance with the goal of reduced incidence of foodborne illnesses. From 1996 to 2002, the size of the population included in the FoodNet surveillance system increased significantly from 14.2 million individuals in five sites to 37.4 million in nine sites. In 1996, FoodNet began active surveillance for laboratory-diagnosed cases of infection from Shiga-toxin-producing E. coli O157:H7. Additional surveillance for cases of hemolytic uremic syndrome (HUS) was added the following year. Most recently, FoodNet also began to collect data on cases of non-Shiga-toxin-producing E. coli in 2000.

According to the Theory of Reasoned Action, the prevailing belief prior to the outbreak was that individuals chose to eat spinach and other vegetables due to their beneficial health properties (18,19). This statement should not disregard the segment of the population that may consume spinach primarily for its gastronomical properties. Subsequent to the outbreak, however, social norms regarding spinach consumption have changed considerably. Wariness of fresh spinach consumption has become the norm and at the height of the outbreak, public sentiment appeared to equate continued consumption of spinach to intentional endangerment of oneself and one’s family. Time will tell how long this sentiment will endure. Although spinach is already beginning to reappear in grocers’ displays and on restaurant menus, the changes necessary to rebuild the trust and confidence of consumers is less certain. Certainly, increasing levels of education on basic food safety, the causes of foodborne illness, and the mechanics of the modern food production system should be included in the strategy to be adopted. Furthermore, targeting increased efforts in certain segments of the population more vulnerable to a long-term decrease in vegetable consumption is recommended. This implies the need for more research to identify these vulnerable populations, as well as quantitative measures of the decrease in consumption over time.


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(7) Examples include: Center for Science in the Public Interest, Union of Concerned Scientists, Organic Trade Association, and Marler Clark, Attorneys at Law.
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(21) Earthbound Farm website. Press Kit, Fact Sheet, updated Oct. 3, 2006. Accessed at: www.ebfarm.com/Press/FactSheet.aspx
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(25) Adler, N.E., and Ostrove J.M., 1999. Socioeconomic Status and Health: What We Know and What We Don’t. Annals of the New York Academy of Sciences, 896: 3-15.
(26) Pollan, Michael, Oct. 15, 2006. “The Way We Live Now: The Vegetable-Industrial Complex,” The New York Times.


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