Predicting intentions to adopt safe home food handling practices. Applying the theory of planned behavior

Abstract

While most home cooks know about safe home food handling procedures, compliance is generally low and has not been much improved by campaigns. Foodborne disease is a common cause of illness, hospitalization and even death, and many of these illnesses are caused by unsafe home food practices. Using the theory of planned behavior as a model, survey data were analyzed. Perceived behavioral control was the strongest predictor of behavioral intentions for both hand washing and food thermometer use. Subjective norm was the next strongest predictor for thermometer use, while attitude towards the behavior was the next strongest predictor for hand washing. This is consistent with earlier focus group results for thermometer use and suggests some possible strategies for designing future home food safety messages.

Introduction

Gaps between knowledge and behavior in health communication campaigns are not unusual. A meta-analysis of 48 health communication campaigns found that, on average, only 7–10% of those who are targeted by a campaign change their behaviors relative to a control group (Snyder, 2001). Campaigns to encourage safe home food preparation are no exception. Most consumers still do not follow recommended safe food handling practices, such as safely defrosting meat and poultry, properly using a food thermometer, safely handling leftovers, and immediately discarding food that may be unsafe (Andress, 1999, Cates, 2002, Godwin et al., 2005, Koeppl, 1998, Kurtzweil, 1999; for a review of studies in Europe, the United States, Canada, Australia and New Zealand, see Redmond & Griffith, 2003).

Media campaigns that are successful at increasing knowledge of and attitudes towards safe food-handling practices have found that actual behavioral compliance often does not follow (Altekruse et al., 1995, McIntosh et al., 1994, Snyder, 2001, Williamson et al., 1992, Woodburn and Raab, 1997). Most people who prepare food at home know the basics of home food safety but do not always practice these behaviors (Wilcock, Pun, Khanona, & Aung, 2004). Clayton, Griffith, and Price (2003) found that, although all 40 participants correctly answered food safety questions regarding hand washing after preparing raw foods and before handling ready-to-eat foods, fewer reported they were very likely to carry out appropriately safe behaviors, and none actually performed the behaviors adequately when they were observed preparing food.

In a national study conducted on young adults, 97% of the sample rated their own food safety knowledge as at least fair, however, 60% did not wash their hands with soap and water, after touching raw poultry (Byrd-Bredbenner et al., 2007). There is a similar knowledge-compliance gap for the use of food thermometers. While most people now own a food thermometer, less than a third use it while cooking large pieces of meat. Even fewer (about 12%) use it while cooking smaller pieces of meat, and only 6% use a thermometer while cooking hamburger (Cates, 2002).

The current study is part of a larger project aimed at designing more effective messages to encourage safe home food handling. A survey explored some of the predictors of two important safe home food handling practices, using a food thermometer and appropriate hand washing. Guiding this study is a general structure based on the theory of planned behavior (see review below), but the goal is also to explore issues that emerged from focus groups conducted by the research team (Porticella et al., 2008; also unpublished data), namely that impression management concerns about presenting oneself as a safe and competent cook could encourage hand washing and discourage food thermometer use. Another factor that emerged was concern about the ease and convenience of performing the behaviors.

Foodborne illness remains a significant health threat with one recent study showing about 82 million annual cases in the U.S. (Scharff, 2010). Others estimate about 325,000 hospitalizations, and 5000 deaths result from foodborne illness in the U.S. each year (Mead et al., 1999). Based on these estimates about one in four Americans suffers from a foodborne illness each year, and 1 in 1000 people is hospitalized for these illnesses. Improper food handling practices in the home are believed to be responsible for approximately one fifth of foodborne illnesses in the U.S. (CDC, 2006). Experts identify keeping food at safe temperatures, using a food thermometer, avoiding cross-contamination, washing hands with soap and water, and avoiding ingestion of foods likely to be contaminated as the most effective practices for reducing various types of foodborne illness (Hillers, Medeiros, Kendall, Chen, & DiMascola, 2003). However, these recommended safe food handling practices are not properly followed by home cooks (Cates, 2002, Cody and Hogue, 2003, Godwin et al., 2005, Redmond and Griffith, 2003).

Studies of home food safety have identified a variety of motivational, behavioral and social barriers to safe food handling practices (Clayton et al., 2003, Shapiro et al., 2006). For one thing home cooks do not think home food handling is a common cause of foodborne illness. While many food safety problems are a result of home food preparation, 85% of home food preparers thought problems were likely to occur outside the home (Kurtzweil, 1999). A number of studies in the U.S. and elsewhere indicate that few respondents think that home food handling is a common cause of illness or perceive home food preparation as a serious threat (Cody and Hogue, 2003, Redmond and Griffith, 2003). Other motivational factors include liking the taste of undercooked meat (Ralston et al., 2002), experience (I have been doing it this way for years and nobody has gotten sick) (Koeppl, 1998), and social concerns (what would my friends think if I kept putting a thermometer in the hamburgers) (Clayton et al., 2003) or other barriers such as time, inconvenience, lack of kitchen equipment, and lack of easy-to-use instructions (Clayton et al., 2003, Koeppl, 1998).

Other studies found that people felt it difficult to incorporate the recommended practices into their cooking procedures. In six USDA-administered focus groups (Koeppl, 1998) targeted at the three most at-risk populations (children, young adults, and senior citizens), respondents provided a variety of reasons for not using a food thermometer, including inconvenience, laziness, and difficulty of use. Clayton et al. (2003) found behavioral and resource barriers to safe cleaning practices, including the belief that appropriate practices took up too much time, effort, and resources (e.g., additional cutting boards/knives and money for “fancy cleaners”), and the perception of safe practices as extra work (e.g., washing extra utensils and cutting boards). Recent focus group participants did not believe that certain recommended behaviors (e.g., using a food thermometer on small pieces of meat) were effective in reducing the health-related risk, and perceived that the recommended behaviors may cost them too much time, money and effort (Porticella et al., 2008).

Compliance or non-compliance may also result from social influences. Recent focus groups (Porticella et al., 2008; also unpublished data) indicate that home cooks were not convinced that foodborne illness was severe or that they were susceptible. Some personal characteristics and normative concerns, such as pride in cooking, may encourage safe home food practices in some situations, but discourage them in others (Porticella et al., 2008). For example, the belief that only inexperienced cooks need to use food thermometers discouraged their use. On the other hand, focus group participants admitted they were more likely to wash their hands if they thought others were looking. A better understanding of the beliefs, values and reasons for compliance or non-compliance with safe home food handling procedures may help in framing messages congruent with those values and that address reasons for non-compliance. Such messages may be more effective in promoting compliance.

Given that knowledge does not appear to be the main barrier to safe food handling practices, the current study aims to explore which of the factors above actually predict compliance with safe home food preparation practices. The theory of planned behavior (Fishbein & Ajzen, 1975) summarizes predictors of behavior as attitudes, social factors, and perceived behavioral control. The theory has frequently been used to identify the attitudinal, social and behavioral facilitators that actually predict the intent to perform a number of behaviors, including health related behaviors. By identifying which factors predict the intent to comply with safe practices we hope to provide guidance for developing home food safety messages.

The study focuses on two specific food handling practices: using food thermometers and washing hands for a full 20 seconds in warm water with soap. The study targets those who at least sometimes prepare meals using raw meat or chicken for a few reasons. Food thermometer use is only relevant for those who cook meat, chicken or fish. Also, while hand hygiene is important for all forms of cooking, the danger of bacterial cross-contamination is much greater for those who start meals with raw meat, poultry or fish than for those who never cook with those materials (for example many vegetarians).

Theory of planned behavior (TPB; Ajzen, 1991; see Fig. 1) was developed from the theory of reasoned action (TRA; Ajzen and Fishbein, 1980, Fishbein and Ajzen, 1975) that proposes specific beliefs that influence behavioral intention and actual behavior. The TPB proposes individuals’ intention to perform a highly specified behavior is a good predictor of actual behavior. Research on TPB finds that attitudes towards the behavior, subjective norms about the behavior and perceived behavioral control are good predictors of a behavior––although specific behaviors may be better predicted by some of those factors and not others. One meta-analysis found that the TPB accounts for “large, highly significant proportions of the variance in prospective measures of both observed (R² = .20) and self-reported (R² = .31) behavior” (Armitage & Conner, 2001). Part of the advantage of the procedures associated with TPB is that they help empirically determine which factors in those general categories best predict the intent to perform a behavior. TPB has shown its predictive validity in various contexts, including a number of food safety issues. It has been successfully applied to predict food consumption and food choice (McCarthy et al., 2004, Shepherd, 1989), hand hygiene practices among Australian college students (Clayton & Griffith, 2008), and food handling behaviors among catering company employees (Mullan & Wong, 2009).

In this study, we aim to apply this framework to investigate the intention to adopt two safe food handling practices: the use of food thermometers and washing hands for a full 20 seconds in warm water with soap. According to the TPB, as a direct determinant of safe food handling behaviors, the behavioral intention (BI) to adopt these handling practices will be influenced by three sets of beliefs: attitudes towards the handling practices (A: defined as an individual's positive or negative evaluation of performing a particular behavior), subjective norms about these practices (SN: defined as an individual's recognition and acceptance of other people's behavioral expectation), and perceived behavioral control over these practices (PBC: defined as an individual's perception of the extent to which performance of the behavior is easy or difficult).

We also expect that the attitude and subjective norm have underlying belief constructs. According to TPB, the attitude towards a given behavior $\left(A={\sum }_{i=1}^p{b}_{i}e\right)$ is assumed as a function of a person's behavioral beliefs (b: defined as an individual's belief about consequences of particular behavior) and outcome evaluations of those beliefs (e: defined as subjective evaluations of the outcome produced by the particular behavior). An estimated value of attitude can be obtained by weighting each salient belief that outcome will occur (b_i, i = 1,…,p) by the evaluative implication of that outcome (e_i, i = 1,…,p). In this study, we focus on individuals’ attitudes towards appropriate hand hygiene and cooking procedures. We reason that one is more likely to have a positive attitude towards using food thermometers or hand washing if one believes that the behavior leads to certain outcomes (e.g., “using food thermometers/washing hands properly can reduce the chance of foodborne illness”) and hence prevent negative outcomes (e.g., “Foodborne illness is a significant risk to my health or my family's health”). Thus, we predict that the attitude towards safe food handling practices (A) is determined by behavioral beliefs about these practices (b) and outcome evaluations (e), regarding to avoidance of foodborne illness.

The subjective norm $\left(\text{SN}\approx {\sum }_{i=1}^{q}n{b}_j{m}_j\right)$ refers to recognition and acceptance by individuals that other people expect them to act in certain ways. It is also determined by a set of salient beliefs about the norms associated with the behavior (nb_j), weighted by the motivation to comply with each of those norms (m_j). Our preliminary investigation in the focus groups revealed a few normative beliefs shared by home cooks (Porticella et al., 2008) with regard to the two food handling procedures. The participants reported perceiving social pressure associated with using food thermometers and hand washing behaviors if their significant others value these behavior as a norm (nb₁). They also reported that adopting these practices was related to their self-presentation as good cooks (nb₂). In this study, we expect that the subjective norms about these food handling practices (SN) will be influenced by these two normative beliefs (nb₁ and nb₂), weighted by different motivations to comply (m₁and m₂).