Consumer Research on Foodborne Illness
Below are research abstracts of consumer research studies conducted or supported by the Center for Food Safety and Applied Nutrition.
The FDA Food Safety Survey: A Data Resource
The U.S. Food and Drug Administration (FDA) Food Safety Survey is a single-stage, random-digit-dialing tracking survey of a nationally representative sample of American consumers. Data were collected in 1988, 1993, 1998, 2001, 2006, and 2010 with sample sizes of 3,202, 1,620, 2,001, 4,482, 4,539, and 4,568, respectively. The purpose of the survey is to track American consumers’ knowledge, behavior, and perceptions on a number of food-safety related topics. These topics include 1) perception of individual and societal risk related to food consumption, 2) food handling, 3) food product safety label understanding and usage, 4) consumption of potentially risky foods, 5) attitude toward new food technologies, 6) perception, knowledge, and experience with foodborne illness, 7) food safety knowledge sources, and 8) consumers’ experience with food allergies. In addition, each wave queries consumers on recent FDA food safety advisories and other topics of current interest to the FDA. The available demographic information includes gender, age, education, race/ethnicity, household size, health status, region, and household income. [Contact: Amy Lando]
Smartphones, tablets, and other personal electronic devices have become ubiquitous in Americans’ daily lives. These devices are used by people throughout the day, including while preparing food. For example, a device may be used to look at recipes and therefore be touched multiple times during food preparation. Previous research has indicated that cell phones can harbor bacteria, including opportunistic human pathogens such as Staphylococcus and Klebsiella spp. This investigation was conducted with data from the 2016 Food Safety Survey (FSS) and from subsequent focus groups to determine the frequency with which consumers use personal electronic devices in the kitchen while preparing food, the types of devices used, and hand washing behaviors after handling these devices. The 2016 FSS is the seventh wave of a repeated cross-sectional survey conducted by the U.S. Food and Drug Administration in collaboration with the U.S. Department of Agriculture. The goal of the FSS is to evaluate U.S. adult consumer attitudes, behaviors, and knowledge about food safety. The FSS included 4,169 adults that were contacted using a dual-frame (land line and cell phone interviews) random-digit-dial sampling process. The personal electronics module was the first of three food safety topics discussed by each of eight consumer focus groups, which were convened in four U.S. cities in fall 2016. Results from the 2016 FSS revealed that of those individuals who use personal electronic devices while cooking, only about one third reported washing hands after touching the device and before continuing cooking. This proportion is significantly lower than that for self-reported hand washing behaviors after touching risky food products such as raw eggs, meat, chicken, or fish. Results from the focus groups highlight the varied usage of these devices during food preparation and the related strategies consumers are using to incorporate personal electric devices into their cooking routines. [Contact: Amy Lando]
This research examines the sources from which U.S. consumers obtain their food safety information. It seeks to determine differences in the types of information sources used by U.S. consumers of different sociodemographic background, as well as the relationships between the types of information sources used and food safety risk perceptions. Analyzing the 2010 Food Safety Survey (N = 4,568) conducted by the U.S. Food and Drug Administration, we found that age, gender, education, and race predicted the use of different sources for food safety information. Additionally, use of several information sources predicted perceived susceptibility to foodborne illnesses and severity of food contamination. Implications of the findings for food safety risk communication are discussed. [Contact: Linda Verrill]
Safe in-home food preparation is the last line of defense for preventing foodborne illness. The Food Safety Survey assessing consumers' food handling behavior has been conducted every 3-5 years (1993, 1998, 2001, 2006, 2010) using a random digit telephone sample of United States adult consumers. Sample sizes ranged from 1620 to 4547. A previous analysis of this data has examined trends in safe food handling (as measured by washing hands and/or cutting boards after touching/cutting raw meat or chicken and by washing hands after cracking eggs). We continue and expand this analysis by modeling the unique effects of age, survey period (year) and birth cohort on safe food handling. We find that age, period, and cohort effects are relevant in measuring changes in food handling behavior; however, the effects are not similar in size or apparent mediating process. The strongest effect is period, followed by age and cohort. Thus it appears contemporaneous changes in information activity can make relatively large short-run improvements, whereas changes in one's maturation and accumulated experience have quadratic effects, and the unique shared experience of cohort leaves its own definite long-lasting imprint. We propose that the birth cohort effects can be explained by the food safety environment during young adulthood. Those who were young adults in two critical time periods – before 1940 when there were widespread foodborne infections and immediately after the 1993 outbreak of Escherichia coli O157:H7 – have better food handling behaviors. [Contact: Amy Lando]
Hand washing is a simple and effective but easily overlooked way to reduce cross-contamination and the transmission of foodborne pathogens. In this study, we used the propensity score matching methodology to account for potential selection bias to explore our hypothesis that always washing hands before food preparation tasks is associated with a reduction in the probability of reported foodborne illness. Propensity score matching can simulate random assignment to a condition so that pretreatment observable differences between a treatment group and a control group are homogenous on all the covariates except the treatment variable. Using the U.S. Food and Drug Administration's 2010 Food Safety Survey, we estimated the effect of self-reported hand washing behavior on the probability of self-reported foodborne illness. Our results indicate that reported washing of hands with soap always before food preparation leads to a reduction in the probability of reported foodborne illness. [Contact: Linda Verrill]
Vegetables and fruits may become contaminated with pathogens anywhere along the farm-to-plate continuum. There-fore, the FDA recommends that vegetables and fruits that have not already been washed be washed by the consumer before slicing or consuming them. The FDA included in its 2006 and 2010 Food Safety Survey a series of questions about purchasing and washing of strawberries, tomatoes, cantaloupes, and bagged, pre-cut lettuce. The Food Safety Survey is a telephone survey tracking consumers' knowledge, attitudes and behaviors related to food safety. In 2006, of those who buy these products, 98% wash strawberries, 97% wash tomatoes, 57% wash cantaloupes and 54% wash bagged pre-cut lettuce. Overall, for both years, more women than men wash cantaloupes, and more men than women wash bagged pre-cut lettuce. Cantaloupe washing declined from 2006 to 2010 for men, while lettuce washing increased for women in the same period. Targeted education campaigns should emphasize the importance of washing produce, especially fruits with hard rinds. [Contact: Linda Verrill]
Food safety research has shown that the use of a food thermometer is the best way to ensure that meat, poultry, and other foods reach an internal temperature sufficient to destroy foodborne pathogens. The 1998, 2001, 2006, and 2010 Food Safety Surveys were used to analyze changes in food thermometer ownership and usage for roasts, chicken parts, and hamburgers in the United States. A probit regression model was used to evaluate differing trends in ownership across demographic subgroups, and probit models with sample selection were used to evaluate differing trends in food thermometer usage for roasts, chicken parts, and hamburgers. The Food Safety Surveys are nationally representative telephone surveys tracking consumers' food safety attitudes and behaviors. Findings from these surveys indicate that the percentage of consumers who own food thermometers has increased from 49% in 1998 to 70% in 2010 (P < 0.05). The use of food thermometers has also increased over this time period but varies by food type. Of those who own food thermometers, a higher percentage reported using thermometers for roasts (76% in 1998 and 82% in 2010, P < 0.05) than for chicken parts (33% in 1998 and 53% in 2010, P < 0.05) and hamburgers (14% in 1998 and 23% in 2010, P < 0.05). The results also show that men, non-Hispanic whites, those with some college education or higher, those with higher incomes, and those 65 years and older were more likely to own food thermometers. After controlling for food thermometer ownership, those aged 18 to 29 years were more likely to use a food thermometer for roasts and chicken parts than those aged 65 to 101 years. The results suggest that educational programs encouraging food thermometer usage should focus first on food thermometer ownership. [Contact: Amy Lando]
Although survey results measuring the safety of consumers’ food handling and risky food consumption practices have been published for over 20 years, evaluation of trends is impossible because the designs of published studies are not comparable. The Food Safety Surveys used comparable methods to interview U.S. adults by telephone in 1988, 1993, 2001, 2006, and 2010 about food handling (i.e., cross-contamination prevention) and risky consumption practices (eating raw or undercooked foods from animals) and perceived risk from foodborne illness. Sample sizes ranged from 1,620 to 4,547. Responses were analyzed descriptively, and four indices measuring meat, chicken, and egg cross-contamination, fish cross-contamination, risky consumption, and risk perceptions were analyzed using generalized linear models. The extent of media coverage of food safety issues was also examined. We found a substantial improvement in food handling and consumption practices and an increase in perceived risk from foodborne illness between 1993 and 1998. All indices were stable or declined between 1998 and 2006. Between 2006 and 2010, the two safe food handling practice indices increased significantly, but risk perceptions did not change, and safe consumption declined. Women had safer food handling and consumption practices than men. The oldest and youngest respondents and those with the highest education had the least safe food handling behaviors. Changes in safety of practices over the survey years are consistent with the change in the number of media stories about food safety in the periods between surveys. This finding suggests that increased media attention to food safety issues may raise awareness of food safety hazards and increase vigilance in food handling by consumers. [Contact: Amy Lando]
Risk communication strategies related to food terrorism (FT) threats should reflect an in-depth understanding of consumers’ perceptions, priorities, and information needs related to those threats. To support development of communication strategies, we used a mental models approach to risk communication method to design, conduct and analyse 50 semi-structured telephone interviews with US adults. Interviewees generally lacked well-defined mental models specific to FT, and, instead, drew on their perceptions of terrorism in general, accidental contamination, product recalls, and emergency preparedness. Assessments of their personal threat of FT were influenced by their beliefs about the nature of terrorism, their confidence in government and the food system to prevent and respond to terrorism threats, and their personal control over food choices. These qualitative research results support guidance for developing and implementing consumer-focused FT risk communications strategies. [Contact: Linda Verrill]
In the 1970s several states in the Great Lakes region became concerned about mercury contamination in lakes and rivers and were the first to issue local fish consumption advisories. In 2001, the Food and Drug Administration (FDA) advised pregnant women, nursing mothers, young children, and women who may become pregnant not to consume shark, swordfish, king mackerel, and tilefish and recommended that these women not exceed 12 ounces of other fish per week. In 2004, FDA reissued this advice jointly with the U.S. Environmental Protection Agency (EPA) and modified it slightly to provide information about consumption of canned tuna and more details about consumption of recreationally caught fish. Though several studies have examined consumers’ awareness of the joint FDA and EPA advisory as well as different state advisories, few used representative data. We examined the changes in awareness and knowledge of mercury as a problem in fish using the pooled nationally representative 2001 and 2006 Food Safety Surveys (FSS) with sample sizes of 4482 in 2001 and 2275 in 2006. Our results indicated an increase in consumers’ awareness of mercury as a problem in fish (69% in 2001 to 80% in 2006, p<.001). In our regression models, we found that in both years, parents having children less than 5 years of age were more aware of mercury in fish and knowledgeable about the information contained in the national advisories about mercury in fish (p<.01) than other adults. In both 2001 and 2006, women of childbearing age (aged 18–45) were less aware and knowledgeable about this information than other women. However, women of all age groups had larger gains in awareness and knowledge than their male counterparts during this time. Participants’ race, education, income, region, fish preparation experiences, having a foodborne illness in the past year, and risk perceptions about the safety of food were significant predictors of their awareness and knowledge. [Contact: Amy Lando]
Older adults are considered more vulnerable to foodborne illness due to lowered immune function. We compared the food safety perceptions and practices of older and younger adults and determined associations with demographic characteristics. We focused on 1,317 participants ≥60 years of age from the U.S. Food and Drug Administration’s 2006 Food Safety Survey, a telephone survey of a nationally representative sample of American consumers. We used data on participants ≥60 years of age to compare younger and older adults, and used Pearson’s Chi-square tests to determine whether perceptions and practices differed by age, gender, level of education, living arrangement, and race/ethnicity. We conducted multiple logistic regression analysis to assess relationships of demographic characteristics and food safety perceptions with food safety practices of older adults. We found that adults ≥60 years of age were more likely to follow recommended food safety practices than those <60 years of age. Sixty-six percent of adults ≥60 years of age reported eating potentially hazardous foods in the past year compared with 81% of adults <60 years of age. Among people ≥60 years of age, women, those with less education, and nonwhite individuals generally had better food safety practices and a greater awareness of food safety risk. These findings suggest that certain subsets of the older adult population are less likely to follow recommended food safety practices and, thus, are at greater risk of foodborne illness. Food safety education for older adults should target men and those with more education and higher incomes. [Contact: Linda Verrill]
The relationship between risk perception and risk avoidance is typically analyzed using self-reported measures. However, in domains such as driving or food handling, the validity of responses about usual behavior is threatened because people think about the situations in which they are self-aware, such as when they encounter a hazard. Indeed, researchers have often noted a divergence between what people say about their behavior and how they actually behave. Thus, in order to draw conclusions about risk perceptions and risk avoidance from survey data, it is important to identify particular cognitive elements, such as those measured by questions about risk and safety knowledge, risk perceptions, or information search behavior, which may be effective antecedents of self-reported safety behavior. It is also important to identify and correct for potential sources of bias that may exist in the data. The authors analyze the Food and Drug Administration's 1998 Food Safety Survey to determine whether there are consistent cognitive antecedents for three types of safe food practices: preparation, eating, and cooling of foods. An assessment of measurement biases shows that endogeneity of food choices affects reports of food preparation. In addition, response bias affects reports of cooling practices as evidenced by its relation to knowledge and information search, a pattern of cognitive effects unique to cooling practices. After correcting for these biases, results show that practice-specific risk perceptions are the primary cognitive antecedents of safe food behavior, which has implications for the design of effective education messages about food safety. [Contact: Amy Lando]
We investigate the causes of consumer uncertainty regarding storage of packaged foods by examining the characteristics of the consumers, the type of food products and packaging, and the where the product was stored at purchase. Consumers’ self-reported refrigeration practices from the 1998 Food Safety Survey are analyzed descriptively and by logistic regression. Eleven percent of the 2,001 respondents reported difficulty during the past three months in deciding whether to refrigerate a packaged food. When consumers do have difficulty, it is likely that the products either are new to them or need to be stored in an unexpected way. The most likely to report uncertainty about whether to refrigerate were people of middle age and people likely to be more attuned to food safety issues – those who have some college or higher education, who look at many sources of food information, and who thought that a household member had a recent foodborne illness. The results suggest that additional education may be needed to inform consumers about proper refrigeration and that storage information on packages is particularly important for foods that are stored at room temperature until opened but that then need refrigeration. [Contact: Amy Lando]
We investigate American consumers’ awareness and perceived risk of pesticide and antibiotic residues in food, and how socioeconomic characteristics affect the awareness and risk perception. Based on a 2001 national telephone survey, we employ a statistical approach that accommodates correlations between the two issues and the fact that perceived risk was collected in the survey only from those who were aware of a given issue. Most individuals have heard of pesticide residues but only some have heard of antibiotic residues, though the latter were perceived as a more serious food safety problem than the former. Awareness of one residue problem is associated with a lower perceived risk of the other problem. Income, age, college-or-more education, and being the main meal preparers are related to more awareness of the two issues. Awareness of pesticide residues is lower among Hispanics and blacks, while awareness of antibiotic residues is lower among blacks. Among those who had heard of pesticide residues, the perceived risk of the residues was higher with higher income and being a Midwest resident and lower with a larger number of adults in the household, being a female, older, Hispanic or black, and being a main meal preparer in the household. Among those who had heard of antibiotic residues, the perceived risk of the residues was higher with higher income and being a Hispanic and lower being a female or black. Results also suggest that our statistical approach is worth considering in future research of similar topics. [Contact: Chung-Tung Lin]
Each year in the United States, microbial pathogens cause millions of cases of foodborne disease and result in many hospitalizations and deaths. Effective consumer education programs to promote safer food handling practices and other averting behaviors may benefit from consumer awareness of microbial pathogens. This paper investigates US consumers’ awareness of four major microbial pathogens (Salmonella, Campylobacter, Listeria and Escherichia coli) as food safety problems, using a multivariate probit model. The awareness varies among pathogens and the variations appear to be related to differences in the number and severity of illnesses associated with these pathogens. Our findings suggest that awareness of microbial pathogens is associated with food safety perceptions, awareness of potentially risky foods and substances associated with potential food safety hazards, food safety related behaviors, and demographics. There are differentiated effects of variables on awareness of the four pathogens. [Contact: Chung-Tung Lin]
Consumers' Assessment of the Food Safety Problem for Meals Prepared at Home and Reactions to Food Safety Labeling. 2001. Brian Roe, Mario F. Teisl, Alan S. Levy, Kevin Boyle, Mark L Messonnier, T. Lynn Riggs, Melissa J. Herrmann, and Felicia M. Newman. Journal of Food Products Marketing 6(4):9-26.
To identify if differences in food safety risk can be effectively and credibly communicated, we conducted eight focus groups. This article summarizes these focus groups and reports how consumers frame the issues surrounding the food safety problem and how consumers react to label-based communications of food safety characteristics. We find consumers have broad, moderate food safety concerns, a wide but spotty understanding of food borne illness prevention and consequences, and a healthy skepticism concerning food safety claims. We identity two forms of labeling that show promise with regard to consumer acceptance and credibility in communicating brand-level and package-level differences in the risk of food borne illness and discuss implications for consumer valuation of such differences. [Contact: Amy Lando]
Data from national telephone surveys conducted in 1988 and 1993 were used to describe consumer perceptions of foodborne illness. The 1993 data were also used to assess the relationship between the perception that a foodborne illness had recently been experienced and awareness, concern, knowledge, and behavior related to food safety. Respondents described foodborne disease primarily as a minor illness without fever that occurs within a day of eating contaminated food prepared in a restaurant. However, several common pathogens have latency period longer than a day, and experts on foodborne disease estimate that most cases of foodborne illness originate from foods prepared at home. In both surveys, people 18 to 39 years of age were more likely than those in other age groups to believe they had experienced a foodborne illness. In 1993, people with at least some college education were more likely to believe they had experienced foodborne illness than were people with less education. People who believed they had experienced foodborne illness had greater awareness of foodborne microbes and concern about food safety issues, were more likely to eat raw protein foods from animals, and were less likely to practice safe food handling than were those who did not perceive that they had experienced such an illness. [Contact: Chung-Tung Lin]
Although not well quantified, a portion of food-borne illness results from voluntary behaviors that are entirely avoidable, such as eating raw foods of animal origin or engaging in unsafe food preparation practices. A telephone survey of 1,620 respondents was conducted to assess the prevalence of selected self-reported food consumption and preparation behaviors associated with increased risks of food-borne illness and the demographic characteristics related to such behaviors. The percentages of survey respondents who reported consuming raw foods of animal origin were 53%, raw eggs; 23%, undercooked hamburgers; 17%, raw clams or oysters; and 8%, raw sushi or ceviche. A fourth of the respondents said that after cutting raw meat or chicken, they use the cutting board again without cleaning it. Safer food consumption and preparation behaviors were consistently reported by persons who were female, were at least 40 years old, and had a high school education or less. These findings suggest that risky food consumption and preparation behaviors are common in the United States and that educational campaigns aimed at changing these behaviors may need to be targeted to specific groups of persons. [Contact: Amy Lando]
A national telephone survey was conducted of 1,620 randomly selected U.S. residents who spoke English, were at least 18 years old, and resided in households with kitchen facilities. Respondents were interviewed about their recognition of foodborne pathogens, foods at risk for transmitting infection, knowledge of safe food handling, and food handling practices. One-third of the respondents who prepared meals reported unsafe food hygiene practices: e.g., they did not wash hands or take precautions to prevent cross-contamination from raw meat. Unsafe practices were reported more often by men, persons 18 to 29 years of age and occasional food preparers than by women, persons 30 years old or older, and frequent food preparers. Respondents who identified a food vehicle for Salmonella spp. were more likely to report washing their hands and cleaning cutting boards after preparing raw meat and poultry. The results raise concerns about consumer food-handling practices. The influence of food safety training, food-handling experience, and age on food-handling practices should be studied further. Awareness of a food vehicle for Salmonella spp., for example, may indicate knowledge of the etiology of foodborne disease that promotes safe food handling. Understanding the factors associated with safe food handling will assist in development of effective safe-food instruction programs. [Contact: Amy Lando]