An Application of the Theory of Planned Behavior—A Randomized
Controlled Food Safety Pilot Intervention for Young Adults
Alyssa C. Milton and Barbara A. Mullan
University of Sydney
Objective: Approximately 48 million Americans are affected by foodborne illness each year. Evidence
suggests that the application of health psychology theory to food safety interventions can increase
behaviors that reduce the incidence of illness such as adequately keeping hands, surfaces and equipment
clean. This aim of this pilot study was to be the first to explore the effectiveness of a food safety
intervention based on the Theory of Planned Behavior (TPB). Methods: Young adult participants (N =
45) were randomly allocated to intervention, general control or mere measurement control conditions.
Food safety observations and TPB measures were taken at baseline and at 4-week follow-up. Within and
between group differences on target variables were considered and regression analyses were conducted
to determine the relationship between condition, behavior and the TPB intention constructs; attitude,
subjective norm, perceived behavioral control (PBC). Results: TPB variables at baseline predicted
observed food safety behaviors. At follow-up, the intervention led to significant increases in PBC ( p =
.024) and observed behaviors ( p = .001) compared to both control conditions. Furthermore, correlations
were found between observed and self-reported behaviors ( p = .008). Conclusions: The pilot interven-
tion supports the utility of the TPB as a method of improving food safety behavior. Changes in TPB
cognitions appear to be best translated to behavior via behavioral intentions and PBC. Further research
should be conducted to increase effectiveness of translating TPB variables to food safety behaviors. The
additional finding of a correlation between self-reported and observed behavior also has implications for
future research as it provides evidence toward the construct validity of self-reported behavioral measures.
Keywords: social cognition models, theory of planned behavior, behavior change, food safety
Food borne illness continues to be an international public health
concern generating both clinical problems for the individual
(Helms, Vastrup, Gerner-Smidt, & Molbak, 2003) and an eco-
nomic burden for society (Scharff, 2010). Data reports from the
United States of America estimate that the mean economic cost of
food borne illness is approximately $152 billion annually (Scharff,
2010); with 48 million consumers affected by this preventable
disease, resulting in 128,000 hospitalizations and 3,000 deaths
(Centers for Disease Control & Prevention, 2011). The Centers for
Disease Control and Prevention suggest that an effort to lower the
occurrence of foodborne illness by 10% would equate to a de-
crease of approximately five million cases of illness annually
(2011). A cohort that is of particular risk is the young adult
population (18 –29 years) and individuals with education beyond
high school (Byrd-Bredbenner et al., 2007).
Several studies have concluded that consumer education, target-
ing prevention of food borne illness in the domestic environment,
is necessary (Barrett, Penner, & Shanklin, 1996; Gorman, Bloom-
field, & Adley, 2002; Li-Cohen & Bruhn, 2002; Medeiros, Ken-
dall, Hillers, Chen, & DiMascola, 2001; Ropkins & Beck, 2000) as
research has found many consumers do not practice adequate food
safety in the home (Daniels, 1998; Medeiros et al., 2004; Medei-
ros, Hillers, Kendall, & Mason, 2001; Medeiros, Kendall et al.,
2001; Ryan, Wall, Gilbert, Griffin, & Rowe, 1996). These key
educational steps include washing and drying hands correctly for
at least 20 seconds, keeping surfaces and equipment clean, sepa-
rating raw and cooked food, cooking food thoroughly, keeping
food at safe temperatures, and using safe water and raw materials
(World Health Organization, 2006).
In spite of these recommendations, very few studies have fo-
cused on implementing and measuring effectiveness of interven-
tions that have the objective of changing consumer’s food safety
behavior in the domestic environment. Calls have been made in the
literature for food safety interventions to have a greater theoretical
foundation through the use of social cognition models (SCM;
Griffith, Mullan, & Price, 1995; Milton & Mullan, 2010). A recent
systematic review found that only 10 published studies examining
psychosocial food safety interventions had occurred in the devel-
oped world (Milton & Mullan, 2010). The review’s overarching
recommendations included the need for better defined outcome
measures, more rigorous reporting of results and intervention
design, the use of randomized controlled trial protocols, and uti-
lizing SCM to provide a greater theoretical foundation and gain
further insight into the constructs that improve food safety behav-
iors.
Previous use of SCM in the food safety literature focusing on
behavior change has been parsimonious and somewhat conflicting.
Research utilizing the Health Belief Model (HBM) to predict food
This article was published Online First November 7, 2011.
Alyssa C. Milton and Barbara A. Mullan, School of Psychology, Uni-
versity of Sydney, Australia.
Correspondence concerning this article should be addressed to Barbara
A. Mullan, School of Psychology, The University of Sydney, NSW, 2006,
Australia. E-mail: barbara.mullan@sydney.edu.au
Health Psychology © 2011 American Psychological Association
2012, Vol. 31, No. 2, 250 –259 0278-6133/11/$12.00 DOI: 10.1037/a0025852
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