[Emerging Infectious Diseases * Volume 3 * Number 4 * October - December 1997]

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Special Issue

Communicating Foodborne Disease Risk

Baruch Fischhoff and Julie S. Downs
Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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Text Version

      The food industry, like many others, has a risk communication
      problem. That problem is manifested in the public's desire to
      know the truth about outbreaks of foodborne diseases; ongoing
      concern about the safety of foods, additives, and
      food-processing procedures; and continued apathy regarding
      aspects of routine food hygiene. If these concerns are
      addressed in a coherent and trustworthy way, the public will
      have better and cheaper food. However, sloppy risk
      communication can itself cause public health damage. Because
      citizens are ill-equipped to discriminate among information
      sources, the food industry as a whole bears responsibility for
      the successes and failures of its individual members. We review
      risk communication research and practice for their application
      to the food industry.

The guardians of the world's food supply face a communication challenge of
extraordinary complexity. They need to be ready at short notice to deal
with various crises, often involving baffling combinations of foods,
pathogens, handling and distribution practices, dietary norms, and
interactions with medical conditions and medications. Their response to
this challenge may have important health, economic, and even political
implications. Conflicting pressures may come from groups that bear the cost
when the public health response is too swift or too slow. Quick, confident
explanations are expected after outbreaks that may never be fully
understood. When consumers (and producers) need information, they cannot
wait for more research. Consumers can read between the lines, especially
when they perceive their lives or livelihoods at risk. If they misread
messages, the communicators may still be held responsible. Moreover,
consumers know that silence is also a form of communication.

At the same time, the guardians of the food supply must wage a continuing
struggle to improve the handling of food. In the United States, campaigns
are under way for cooking beef more thoroughly, separating raw meat from
salad ingredients, and improving the sanitation of food handlers (e.g.,
Operation Clean Hands). To some extent, these campaigns are the
incarnations of old messages that have not been communicated effectively.
At the same time, the campaigns are responses to changes in the food supply
that have increased the risks associated with conventional practices. For
example, as the incidence or severity of foodborne disease pathogens
increases, the effectiveness of customary food-handling practices
decreases.

This article briefly reviews risk perception and communication research as
a possible resource for better understanding (and perhaps meeting) the
public's needs (1-3). Communication research provides a set of general
tools and theories, as well as a body of results, showing a complex picture
of strengths and weaknesses in lay understanding of risk. We explore here
the implications for anticipating public response to emerging foodborne
pathogens and offer a proposal for how an effective communication campaign
might be organized.

Although risk communication research does not directly address emerging
foodborne pathogens, it is compatible with the model of risk assessment
that the food industry seems to be adopting (4). Drawn from the National
Research Council's (5) volume, Improving Risk Communication, the model
involves overlapping processes of assessing the magnitude of risks (through
analytical procedures), managing their level (through practical measures),
and communicating with the public about them.

Like many other risks, emerging foodborne pathogens are of primary concern
to some specialists but one more thing to worry about for ordinary
citizens. The thought processes that people rely on for making decisions
are the focus of much research (Table; 6).

Table. Thought processes involved in decision-making
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People simplify. Many decisions require people to deal with more details
than they can readily handle at any one time. To cope with the overload,
people simplify. People want to know if foods are "safe," rather than
treating safety as a continuous variable; they demand proof from scientists
who can provide only tentative findings; and they divide the participants
in risk disputes into good guys and bad guys. Such simplifications help
people cope, yet also lead to predictable biases (7).

Once people's minds are made up, it's hard to change them. People are adept
at maintaining faith in their beliefs unless confronted with overwhelming
evidence to the contrary. One psychologic process that helps people to
maintain their current beliefs is underestimating the need to seek contrary
evidence. Another process is exploiting the uncertainty surrounding
negative information to interpret it as consistent with existing beliefs
(8).

People remember what they see. People are good at keeping track of events
that come to their attention (9),(10). As a result, if the appropriate
facts reach people in a credible way before their minds are made up, their
first impression is likely to be the correct one. Unfortunately, it is hard
for people to gain firsthand knowledge of many risks, leaving them to
decipher the incomplete reports they get.

People cannot readily detect omissions in the evidence they receive. It is
unusual both to realize that one's observations may be biased and to undo
the effects of such biases. Thus people's risk perceptions can be
manipulated in the short run by selective presentations. People will not
know and may not sense how much has been left out (11). What happens in the
long run depends on whether the missing information is revealed by other
experiences or sources.

People may disagree more about what "risk" is than about how large it is.
One obstacle to determining what people know about specific risks is
disagreement about the definition of "risk" (12-15). For some risk experts,
the natural unit of risk is an increase in probability of death; for
others, it is reduced life expectancy; for still others, it is the
probability of death per unit of exposure. If lay people and risk managers
use the term "risk" differently, they may agree on the facts of a hazard,
but disagree about its riskiness.

How much does the public know and understand? The answer to this question
depends on the risks consumers face and the opportunities they have to
learn about them. The next section discusses strategies for improving those
opportunities.
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Communicating Risk

An overarching theme of risk communication is that people understand risks
that draw their attention and are presented comprehensibly. Whether the
public's attention is aroused spontaneously or as a result of a message,
the opportunity must be seized. The right information must be selected and
communicated appropriately (1,16,17).

The hallmarks of effective communication should be used. Match the
audience's level of technical sophistication. Do not talk down. Clarify
terms (e.g., virus) that are used in everyday speech but not very precisely
(e.g., risk). Organize information. Provide the audience with a quick
logical overview. Make the desired level of detail easy to read. Use
numbers to communicate quantities. Avoid ambiguous verbal quantifiers, such
as "rare" or "likely". Ensure source credibility. Realize that messengers
are a part of the message and essential to its interpretation. Use
knowledgeable sources that will not misrepresent the message. Avoid risk
comparisons with rhetorical implications. Comparing one uncontrollable
accident risk with another, more familiar one (e.g., half as likely as
being injured by lightning) can be useful; however, people dislike
comparisons that imply they should accept one risk because they accept
another, e.g., comparing the risks of nuclear power with those of eating
peanut butter (from aflatoxin).

However useful communication research may be, there is no substitute for
empirical testing of messages. With heterogeneous audiences, any fixed
message will work better for some people than for others. In such cases,
universal understanding may require providing the opportunity for the
public to ask questions through public information sessions, agricultural
extension services, science teachers, or toll-free numbers.

What To Say

The effort to communicate is wasted if the information is not worth
communicating, either because people already know it or because it makes no
difference to them. Indeed, communication can backfire if consumers think
that their time is being wasted with useless messages while they are being
denied pertinent information. An analytical effort to determine what is
worth knowing and a coordinated empirical effort to determine what people
know already are required. These efforts take different forms in situations
where consumers face well-formulated decisions and need only a few
quantitative estimates before making choices, and in situations where
consumers are trying to understand the processes creating and controlling a
risk, in order to follow public discussion, devise decision options, or
understand quantitative estimates.

Identifying Relevant Estimates

The tools of decision analysis provide ways to determine how sensitive
well-structured choices are to uncertainty in different decision parameters
(18,19). The more sensitive parameters should receive more attention,
unless consumers know them already (and need no reminder). If conditions do
not permit sensitivity analyses for individual decision makers, one can
model the information needs of a population similar to the intended
audience. Merz et al. (20) demonstrated this approach for communicating to
carotid endarterectomy candidates. Scraping out the main artery to the
brain reduces the probability of stroke for patients with arteriosclerosis.
However, the procedure can cause many problems, including strokes. Decision
analysis computed the attractiveness of surgery for a hypothetical
population of patients, with a distribution of physical states (e.g.,
stroke risks) and values (e.g., time horizons). The analysis found that
three of the potential complications (stroke, facial paralysis, and
persistent headaches) posed sufficient risk that learning about them should
dissuade about 30% of candidates from surgery. Learning about the other
side effects should affect few additional patients. Therefore, physicians
trying to secure informed consent should (while not hiding other
information) make sure that patients understand the risks of these three
complications.

Identifying Relevant Processes

Risk analysis provides one way to identify the critical processes in
creating and controlling risks. Figure 1 shows a simple model for the risks
of foodborne pathogens. It uses the formalism of the influence diagram
(21,22). Such a model can be used both to assess risks and to characterize
the comprehensiveness of lay understanding. In this model, people incur
food-related risks as a result of decisions, which possibly lead to actions
or exposures. These decisions concern such actions as eating a bite of
suspicious food, choosing a particular diet, or opting for school (or home)
lunch. Those decisions depend, in part, on the perceived risks of those
actions as well as other nonrisk factors (i.e., other costs and benefits).
Exposure may follow, if a pathogen is actually present; it can lead, in
turn, to transmission of the pathogen and to changed health states,
depending on the resistance to disease that the person's health provides.
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                   Figure 1. Diagram of the general model

Figure 2 elaborates on this model. It shows that food pathogenicity depends
on both the prevalence of pathogens in the environment and the quality of
food handling. A person's own health influences risk perceptions through
the intermediate variable of perceptions of health, which in turn is
influenced by the person's history of food consumption (or avoidance).
Actual pathogenicity influences risk perceptions through awareness, a
variable that communicators might affect. Nonrisk factors include visceral
factors (e.g., hunger), external social factors (e.g., social pressure to
eat any food offered by a host), norms (e.g., not eating dog), and the
expected benefits of consumption (e.g., taste, texture, and other
gustatorial pleasures). Computing risks with this model would require
specifying each variable and estimating the contingencies by using
statistical sources or expert judgment. For risk communication purposes,
even a qualitative model can define the universe of discourse and allow
approximate estimates of the most important relationships (23).
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                 Figure 2. Diagram of the foodborne model.

Identifying Current Knowledge

Determining what people already know about quantitative estimates is
relatively straightforward, although there are various pitfalls (24,25).
Eliciting knowledge of processes is more difficult. Respondents should be
given the focus of the problem and maximum freedom to express their ideas
and reveal which of the processes in Figure 2 are on their minds. Studies
using open-ended techniques often find that people speak the language of
risk without understanding its terms. For example, in a study about radon,
we found that respondents often knew that it was a colorless, odorless,
radioactive gas that caused lung cancer. However, when pressed, respondents
often revealed inappropriate notions of radioactivity, believing that
anything radioactive would permanently contaminate their homes. Some told
us that they would not test for radon because there was nothing that they
could do if they found a problem (26). In studies with adolescents, we
found other forms of false fluency; for example, teens used terms such as
"safe sex" and "clean needles" without understanding them (23). Without
open-ended probing, we miss misconceptions that a technical expert never
would have imagined, or we use language that does not communicate
effectively with our audience (27).

Food Industry Communication Strategies

Technical experts (in any industry) generally want to get the facts in
order before saying anything. Although that is an appropriate norm within
the scientific community, refusing to address a concerned public can evoke
mistrust and anger, as can failing to arouse an apathetic public. To steer
an appropriate course, communicators need an explicit policy that balances
the risks of saying too much with the risks of saying too little. The
policy must consider both what to say and when to say it. From a decision
theory perspective, citizens need information critical to identifying
actions that will help them achieve personal goals. As a result, any
recommendations should reflect both scientific knowledge and citizens'
values. That is, consumers need to know what is the best gamble, given the
trade-offs between, for example, the risks of throwing out good food and
the risks of eating food that might make them sick.

At times, there may be a temptation not to tell it like it is. For example,
one might argue that risks should be exaggerated when a frank report would
leave people unduly apathetic, as judged by their own standards. That is,
people should say "Thanks for getting my attention" once the grounds for
the overstatement were made clear. Such gratitude requires a public that
not only recognizes the limits of its own understanding, but also accepts
paternalistic and manipulative authorities. That acceptance seems more
likely for 
misrepresentations intended to get a complacent public moving
than for ones intended to allay a hysterical public's fears. In either
case, once the secret is out, all future communications may be subjected to
second guessing ("How seriously should we take them this time?").

One situation in which paternalistic authority is needed arises when a
single message must be sent to a heterogeneous audiencefor example, when
officials must decide whether to declare a particular food "safe." Safety
is a continuous variable, and any cut-off represents a value judgment. For
any given food, different groups may face different risks, derive different
benefits, and want to make different trade-offs. For example, a few people
are strongly allergic to sulfur dioxide as a dried food preservative.
Marketing such foods signals their safety to all. Labels that declare
preservatives in foods allow consumers to customize their risk levels, but
only if they know their own risks (i.e., whether they are strongly
allergic, which they may learn only through a bad reaction whose source
they identify).

The Food and Drug Administration faces a similar challenge in its effort to
standardize risk labels for over-the-counter drugs. For example, other
things being equal, producing bilingual labels will require either reducing
print size or omitting information about some side effects. These
modifications would, in turn, increase the risks for consumers with limited
vision (e.g., some of the elderly) or those particularly sensitive to the
omitted effects. Whatever labeling, warning, or communication strategy is
chosen will leave some residual risk, with an uneven distribution depending
on the heterogeneous sensitivities of the audience. Thus, the strategy
reflects the authorities' notion of the "acceptable level of
misunderstanding" (28).

What that acceptable level should be is a political and ethical question,
which could be resolved by properly constituted public or private groups,
and a scientific question, partially resolvable by research of the sort
described here. Rigorous empirical testing is needed to determine whether
communications fulfill the hopes placed in them (27). Emerging foodborne
pathogens provide a particular challenge to safety communicationsand a
particular need for evaluation. Their novelty and ability to produce
outbreaks in diverse places in the world and the food chain encourage
treating them as unique. If a communication strategy is improvised only
when a crisis hits, or as it evolves, the chances for a misstep increase.
Those chances are especially large if the outbreak is the first major risk
problem for the health authorities involved (16).

As a result, communications about these unique situations should be
routine. A standard format for reporting risk information should be
adopted. Funtowicz and Ravetz (29) propose a notation that includes a
best-guess risk estimate (expressed in standard units), a measure of
variability, and a "pedigree" (indicating the quality of the research).
Although new, such notation might become familiar, much as degrees
Fahrenheit, miles per gallon, probability of precipitation, and recommended
daily allowance have become familiar.

Another part of communication planning is to adopt standard scripts for
reporting complex procedural information regarding what citizens should do
and what food specialists are doing. The adoption process should include
empirically testing the comprehensibility of concrete messages with an
audience like the intended audience. Influence diagrams offer one template
for organizing procedural information. Risk analyses provide one way to
identify the crises most likely to occur and may allow not only testing the
most likely messages, but also identifying the persons most likely to do
the communicating and preparing them accordingly. The chemical industry's
Community Awareness and Emergency Response program might provide some
useful lessons in how to organize for unlikely events, although the
challenges of dealing with the relatively identifiable community
surrounding a chemical plant are different from those presented by dealing
with the diffuse national (or even international) audience concerned about
a food. The chemical industry's experience may also provide guidance on how
to achieve voluntary industry compliance with a set of communication
principles. Public goodwill is eroded every time an industry spokesperson
violates the public trust by misrepresenting, or just explaining
inadequately, the state of affairs. Reducing misrepresentation requires
institutional discipline; reducing inadequate communication requires a
scientific approach to communication.

Acknowledgments

Our research was supported in part by the National Institute for Allergy
and Infectious Diseases, the National Institute of Alcohol Abuse and
Alcoholism, and the National Science Foundation.

Address for correspondence: Baruch Fischhoff, Department of Social and
Decision Sciences, Department of Engineering and Public Policy, Carnegie
Mellon University, Pittsburgh, PA 15213, USA; fax: 412-268-6938; e-mail:
baruch@andrew.cmu.edu.

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