The Relationship between Attitudes, Knowledge, and Demographic Variables of High School Teachers Regarding Food Irradiation

Authors

  • B.M. Thompson,

    1. Author Thompson is with Baylor College of Medicine, Houston, TX. Previous address: Texas A&M Univ., College Station, TX 77030. Authors Ribera, Wingenbach, and Vestal are with Texas A&M Univ., College Station, TX 77030. Direct inquiries to author Thompson (E-mail: brittat@bcm.tmc.edu).
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  • K.P. Ribera,

    1. Author Thompson is with Baylor College of Medicine, Houston, TX. Previous address: Texas A&M Univ., College Station, TX 77030. Authors Ribera, Wingenbach, and Vestal are with Texas A&M Univ., College Station, TX 77030. Direct inquiries to author Thompson (E-mail: brittat@bcm.tmc.edu).
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  • G.J. Wingenbach,

    1. Author Thompson is with Baylor College of Medicine, Houston, TX. Previous address: Texas A&M Univ., College Station, TX 77030. Authors Ribera, Wingenbach, and Vestal are with Texas A&M Univ., College Station, TX 77030. Direct inquiries to author Thompson (E-mail: brittat@bcm.tmc.edu).
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  • T.A. Vestal

    1. Author Thompson is with Baylor College of Medicine, Houston, TX. Previous address: Texas A&M Univ., College Station, TX 77030. Authors Ribera, Wingenbach, and Vestal are with Texas A&M Univ., College Station, TX 77030. Direct inquiries to author Thompson (E-mail: brittat@bcm.tmc.edu).
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Abstract

ABSTRACT: The purpose of this study was to use a validated instrument to determine the attitudes and knowledge of high school teachers regarding food irradiation, and to determine the correlations among their knowledge and attitudes and certain demographic variables. Knowledge and attitudes about food irradiation were measured in selected high school family and consumer sciences teachers (n= 121) who taught Food and Nutrition, Food Science and Technology, and/or Food Production Management and Services, via a 24-item instrument with 6 factors. Results revealed these teachers held neutral to positive attitudes about the safety of irradiated foods, their perception of the risk of foodborne illness, and learning about food irradiation, and neutral to negative perceptions of their understanding of food irradiation and their competence to teach about it. These teachers had a moderate knowledge base regarding food irradiation. Teachers' attitudes regarding the safety of food irradiation were positively correlated with their perceived understanding of food irradiation, actual knowledge of it, and competence to teach about it. Their perceived understanding of food irradiation was positively correlated with competence to teach about it, knowledge, and attitudes toward the safety of food irradiation. The only demographic variable correlated with knowledge or attitudes was teachers' previous food irradiation educational experiences. These data suggest the importance of education for family and consumer sciences teachers concerning food irradiation.

Introduction

Food irradiation is a food safety technology that, when used with existing food safety measures, reduces harmful pathogens in food (CAST 1994; Smith and Pillai 2004). This technology has been shown to be safe through hundreds of studies conducted over the last 5 decades (Tauxe 2001; Smith and Pillai 2004). Consumers, however, have been slow to embrace it (Bruhn 1998; Ten Eyck 2002), even though annually an estimated 76 million Americans become ill, 325000 are hospitalized, 5000 die, and billions are spent on health care costs associated with foodborne illnesses (Buzby and others 1996; Mead 1999).

Many factors have been associated with consumer acceptance of food irradiation. In simulated market studies, Aiew and others (2003) provided evidence that lack of knowledge about food irradiation significantly influenced consumers' unwillingness to purchase irradiated food. Troxel (2000) also supported this finding by revealing that persons who reported to be somewhat familiar with food irradiation were more willing to purchase irradiated food than those who were unfamiliar with food irradiation. Studies have also indicated that demographic variables such as ethnicity, level of education, household status, and gender have an impact on consumer acceptance of food irradiation. Specifically, individuals with children under 18 y old as well as those who are concerned about the safety of irradiated foods are less likely to pay more for irradiated food products (Fox 2002; Nayga and others 2004). However, consumers who have a higher level of education, are concerned about the risk of foodborne illness, or have prior knowledge of food irradiation are likely to endorse it (Fox 2002; Nayga and others 2004). While many studies suggest that females and non-Caucasians are less accepting of irradiated foods, other research indicates they may be more likely to pay a premium for these products (Bruhn 1995; Fox 2002; Nayga and others 2004).

Although research has been conducted regarding factors associated with consumers' attitudes toward irradiated foods, less is known about persons who potentially provide education in this area. Research in education indicates that educators' knowledge, attitudes or beliefs, and values influence how and what they teach (Pajares 1992; Munby and others 2002). Limited knowledge in a subject matter has been shown to reduce the amount of time a teacher spends on that subject (Czerniak and Chiarelott 1990). Not only is subject matter knowledge important, so too are attitudes or beliefs and values. Expectancy-value theory proposes that an individual's behavior is influenced by beliefs in his/her ability, or self-efficacy (Bandura 1997), as well as his/her value of a specific activity (Wigfield and Eccles 2000).

Recent research with community-based nutrition and health educators, specifically family and consumer sciences county extension educators, indicates their perceived understanding about food irradiation and its safety influenced the amount of education they provided to clients on this topic (Thompson and Knight 2006a, 2006b). In addition, the amount of teaching experience of these educators influenced their beliefs toward the safety of food irradiation (Thompson and Knight 2006a).

The primary purpose of this study was to explore and describe family and consumer sciences high school teachers' attitudes and knowledge of food irradiation. The objectives of this study included the following: to identify the attitudes and knowledge of family and consumer sciences high school teachers' regarding food irradiation and to explore relationships among selected demographic variables with attitudes and knowledge.

Materials and Methods

Participants and instrument administration

Data were collected from 121 family and consumer sciences high school teachers in Texas. Family and consumer sciences high school teachers were of interest because they provide knowledge and guidance about “things of everyday life,” including food for basic nutrition and health and future scientific developments in the creation of foods, so that individuals can make informed decisions contributing to a healthy, productive, and more fulfilling life (Baugher and others 2005). We were specifically interested in those teachers who taught Food and Nutrition, Food Science and Technology, and/or Food Production Management and Services because of the direct link of food safety and food irradiation education to the state-required family and consumer sciences essential knowledge and skills in these areas (Texas Education Code 1998). The researchers first obtained a list of available e-mail addresses of family and consumer sciences high school teachers in Texas who taught at least one of the above mentioned subjects. At the time of the study, the number of family and consumer sciences teachers who taught the above selected subjects was unknown because of teachers' differing family and consumer sciences course offerings throughout the school year. Of the 495 identified, we randomly selected a sample of 216 for our study based on a 0.95 confidence level and an error rate of 0.05 (Krejcie and Morgan 1970; Isaac and Michael 1995). Four e-mail addresses were unusable, resulting in 212 possible respondents. The total responses received were 121, for a response rate of 57.1%.

The questionnaire was administered via the Web. An introductory e-mail providing information about the project with a direct link to the questionnaire was sent to all randomly selected participants. The questionnaire was administered over a 6-wk period in which 3 separate follow-up e-mails were sent to nonresponders every 2 wk to reduce the nonresponse rate. The Texas A&M Univ. Institutional Review Board approved this study.

Demographics revealed that approximately two-thirds of the participants had taught family and consumer sciences for 11 y or more, with 37% having taught 21 y or more (Table 1). Most felt that they had a good to excellent understanding of food safety. Participant demographics revealed that most were 40 y old and above, Caucasian, and educated with at least a bachelor's degree. Over one-third had earned a graduate degree. Most (79%) indicated they had never attended a workshop or other educational training on food irradiation. More detailed demographic frequencies are provided in Table 1.

Table 1—.  Frequency analysis of selected demographic variables of participating family and consumer sciences high school teachers (n= 121)
Demographic variablesNumber of participants (%)
  1. aDenotes missing data. Percentages reported are calculated based on number of completed responses for the item.

Teaching experience (years)a
  0–519 (16.0)
  6–1019 (16.0)
 11–2037 (31.0)
 21+44 (37.0)
Highest level of education
 Bachelors75 (62.0)
 Masters42 (34.7)
 Other4 (3.3)
Ethnicity
 Caucasian109 (90.1) 
 African American6 (5.0)
 Hispanic5 (4.1)
 Other1 (0.8)
Age (years)
 <305 (4.1)
 30–3918 (14.9)
 40–4932 (26.5)
 50–5957 (47.1)
 60+9 (7.4)

Instrument

To document the food irradiation attitudes and knowledge of family and consumer sciences high school teachers, we modified a validated instrument used to collect data with family and consumer sciences county extension agents, referred to as the Food Irradiation Educator Survey (FIES) (Thompson and Knight 2006a). The FIES had 14 attitudinal items and 2 scales, Safety and Understanding, with a reliability of 0.89 and 0.75, respectively. Our modified instrument, the Food Irradiation Teacher Assessment (FITA), solicited teachers' responses to 19 attitudinal items on a 5-point scale from “strongly agree” to “strongly disagree” and 2 self-rating items about their understanding of food irradiation on a 4-point scale from “excellent” to “poor.” Six multiple-choice items were adapted for use based on item statistics of previously validated items (Thompson 2004) that specifically addressed common food irradiation misconceptions. An example of a multiple-choice item was: “Compared to cooked or frozen food, food that is irradiated at approved doses has:” (Answer: “similar nutritional value”).

Validity and reliability Both validity and reliability were determined for the instrument. Construct validity was determined through exploratory factor analysis to assess the underlying structure of the attitudinal items. In addition, construct validity was also established through theoretical fit (Kim and Mueller 1978) to identify factors or scales of the items. Three experts associated with the field of food irradiation and food safety reviewed all items of the FITA for content validity and 3 educators reviewed it for face validity. Reliability for the attitudinal and self-assessment items was analyzed using Cronbach's α; Kuder-Richardson 20 was used for the multiple-choice knowledge items. All data were analyzed using SPSS 12.0 (SPSS Inc., Chicago, Ill., U.S.A.); the α for our study was set at 0.05.

To determine validity of the attitudinal items (19 items), we conducted principal components factor analysis with varimax (orthogonal) rotation. Five factors were identified using the Kaiser criterion of eigenvalues greater than or equal to 1.0 as well as a scree plot (Kim and Mueller 1978; Nunnally and Bernstein 1994). These 5 factors accounted for 68.34% of the total variance. Table 2 provides the total variance for which each factor accounted. Items that loaded 0.40 or above on a factor were considered to be part of that factor. Nine items loaded on the 1st factor, 3 on the 2nd and 3rd, and 2 on both the 4th and 5th factors (Table 2). Items in the 1st factor were conceptually related to the safety of food irradiation and therefore referred to as Safety, similar to previous results (Thompson and Knight 2006a). Most items loading on the 2nd factor related to teachers' self-efficacy beliefs about teaching food irradiation (Competence), while items in the 3rd factor related to attitudes toward the value of learning about food irradiation (Learning). Items in the 4th factor were related to participants' views of the risks of foodborne illness in the United States (Foodborne Illness Risk), and items in the 5th factor addressed contamination of food (Contamination). To provide further evidence of the structure of our instrument, the reliability of each factor was analyzed.

Table 2—.  Exploratory factor analysis of the FITA using principal components factoring with varimax rotation
ItemsFactor loadingsa
1b2c3d4e5f
  1. aLoadings < 0.40 are omitted.

  2. bSafety.

  3. cCompetence.

  4. dLearning.

  5. eFoodborne illness risk.

  6. fContamination.

 1. I believe foodborne illness caused from bacteria in meats is a problem in the U.S.0.84 
 2. I believe that foodborne illness caused from bacteria in fruits and vegetables is a problem in the U.S.0.81 
 3. I am interested in learning more about food safety technologies. 0.74 
 4. Not enough research has been conducted to prove that food irradiation is safe. 0.66 
 5. Irradiation can be used to make spoiled food marketable.0.76
 6. Irradiation will make food radioactive. 0.76 
 7. Food irradiation destroys the nutritional content of food more than other processing techniques. 0.63 
 8. Irradiation can effectively eliminate pathogens in food.  0.56 
 9. Consuming irradiated food could be harmful to me in the future. 0.72 
10. I would buy irradiated food if it was available. 0.82 
11. Irradiation facilities give off radiation to the surrounding community. 0.61 
12. I feel competent teaching about food irradiation.  0.87 
13. Food that has been irradiated is safe to eat. 0.79 
14. Food that has been irradiated can become re-contaminated.0.73
15. Irradiated food causes cancer. 0.69 
16. I would serve irradiated food to my family. 0.89 
17. Students will benefit from knowing about food irradiation. 0.76 
18. I am interested in learning more about food irradiation. 0.90 
19. I feel confident teaching about food irradiation.  0.92 
Eigenvalues 6.10 2.33 1.831.571.15
Variance accounted for (%)27.1111.9511.549.678.07

The reliability of the scales, or factors, was determined using Cronbach's α coefficient. The coefficient α of the 1st (Safety), 3rd (Learning), and 4th (Foodborne Illness Risk) factors was 0.89, 0.75, and 0.82, respectively, with each item correlating highly to its respective scale (r= 0.40 or above). The reliability of the Safety scale was the same compared to a previous study with family and consumer sciences county extension agents. The coefficient α of the 2nd factor (Competence) was 0.74; correlation of item 8 (“Irradiation can effectively eliminate pathogens in food”) was weakly correlated with the remaining items on the scale (below r= 0.40), and elimination of this item resulted in a substantial increase in both reliability (coefficient α= 0.87) and theoretical fit of the remaining items on the factor. Analysis of the 5th factor (Contamination) indicated poor reliability (coefficient α= 0.48). With such low reliability, this scale was eliminated from the analysis.

In addition, 2 self-assessment rating items (Understanding), “How would you rate your knowledge of food irradiation?” and “How would you rate your understanding of the technology behind food irradiation?” were also analyzed for reliability using Cronbach's α coefficient, and the 6 multiple-choice knowledge items (referred to as Knowledge) were analyzed using Kuder-Richardson 20. Internal consistency reliability for Understanding was 0.84. A previous study with family and consumer sciences county extension agents revealed an internal consistency reliability of 0.75 for the Understanding scale (Thompson and Knight 2006a). Reliability of the Knowledge items yielded a coefficient α of 0.57. Although this coefficient was low, due to issues such as the limited number of multiple-choice knowledge items, it was within acceptable range (Switzer and others 1999). Therefore, based on factor analysis, reliability analysis, and theoretical fit, our instrument consisted of the following factors: Safety (9 items), Competence (2 items), Learning (3 items), Foodborne Illness Risk (2 items), Understanding (2 items), and 6 multiple-choice knowledge items (Knowledge).

Descriptive and correlation analysis To determine the score for each of the scales, each attitudinal and rating item was coded so that higher scores reflected more favorable attitudes to food irradiation. Items within each scale were then summed. For understandability, summed results are presented as a mean average (sum divided by the number of items in the scale). To determine the correlation between food irradiation factors, analyses were conducted using Pearson product moment correlation or Spearman Rho, depending on the type of data.

Results

Attitudes and knowledge

Analysis revealed that participants held neutral to positive attitudes toward the safety of food irradiation (Safety), the risk of foodborne illness (Foodborne Illness Risk), and learning about food irradiation (Learning). Table 3 provides the mean, standard deviation, and 95% confidence intervals for each scale. However, they held neutral to negative self-efficacy attitudes regarding their competence to teach about food irradiation (Competence). In addition, analysis indicated that participants perceived their understanding of food irradiation to be limited. Results from the multiple-choice items (Knowledge) indicated that they answered an average of 4 out of 6 items correctly.

Table 3—.  Statistics of FITA scales with family and consumer sciences high school teachers (n= 121)
ScaleMeanSD95% CI
  1. aScale mean of items on a 5-point scale.

  2. bScale mean of items on a 4-point scale.

  3. cMean number of 6 multiple-choice items answered correctly.

Safetya3.400.633.28–3.52
Foodborne illness riska3.590.863.44–3.75
Learninga4.630.414.56–4.80
Competencea2.350.992.17–2.53
Understandingb1.480.611.37–1.59
Knowledgec4.261.374.00–4.52

Correlations

Previous studies have indicated that, in general, gender, ethnicity, level of education, prior knowledge regarding food irradiation, perceptions about the safety of food irradiation, and amount of teaching experience (for educators) are associated with attitudes toward food irradiation (Troxel 2000; Fox 2002; Fox and others 2002; Nayga and others 2004; Thompson and Knight 2006). Since our sample of family and consumer sciences high school teachers included almost all females who were mostly Caucasian, we were unable to explore the relationship of gender and ethnicity with attitudes.

Safety We hypothesized that teachers' attitudes toward the safety of food irradiation would be positively associated with their perceived understanding of it, their knowledge about it, any previous training on the topic, their attitudes toward the value of food irradiation education, and their attitudes toward the risk of foodborne illness. We also posited that teachers' level of education and amount of teaching experience would be significantly positively correlated with Safety. Analysis indicated that only teachers' Understanding, Knowledge, and previous training were significantly positively correlated with their attitudes toward the safety of food irradiation (Table 4). The effect size for these correlations, or the degree of practical significance of the associations, was a medium effect size, or of moderate practical importance (Hojat and Xu 2004). We also found that Competence to teach about food irradiation was statistically significantly correlated with Safety (a medium effect size). However, participants' level of education, teaching experience, perception of the risk of foodborne illness, or education about the topic were not correlated with Safety.

Table 4—.  Correlations between FITA scales and demographic variables
 SafetyCompetenceLearningFoodborne illness riskUnderstandingKnowledgePrevious FI learningTeaching experienceEducational level
  1. aCorrelation is significant at the 0.01 level.

  2. bCorrelation is significant at the 0.05 level.

Safety 
Competence 0.31a 
Learning 0.19  0.01  
Foodborne illness risk−0.02 −0.03   0.27a 
Understanding 0.46a 0.69a 0.15 0.09 
Knowledge 0.34a 0.06  0.08  0.26a  0.24b 
Previous FI learning 0.34a 0.19b 0.08 0.03  0.38a 0.13 
Teaching experience 0.03 −0.07 −0.14−0.13−0.06−0.06−0.14 
Educational level 0.03  0.02 −0.05−0.05−0.03−0.01−0.080.13

Understanding We anticipated that teachers' Understanding of food irradiation would be positively related to not only their attitudes toward the Safety of it but also to their actual knowledge and previous training on the topic. Analysis indicated that Knowledge and previous training were statistically significantly positively correlated with Understanding; these correlations were a small to medium effect size (Table 4).

Competence Based on research within the field of education, specifically self-efficacy beliefs, we hypothesized that Knowledge, Understanding, previous food irradiation education, and the value of learning about food irradiation would be statistically significantly positively associated with Competence. Interestingly, analysis indicated that Understanding as well as Safety was statistically significantly positively related. This correlation was large in terms of effect size. No statistically significant correlations were noted between Competence and Learning, Knowledge, or previous food irradiation educational experiences.

Previous food irradiation training We hypothesized that teachers who had participated in opportunities to learn more about food irradiation would not only have positive attitudes toward the safety of irradiated foods, understanding of the technology, and competence to teach about it, they would also have a better knowledge base and increased interest in learning about the topic. Results showed no statistically significant correlations between teachers' previous training on the topic and their knowledge about it or their attitudes regarding learning about it.

Conclusion

The purpose of our study was to investigate the attitudes and knowledge of family and consumer sciences high school teachers concerning food irradiation and to determine the correlation among selected demographics, attitudes, and knowledge. We modified an instrument specifically for teachers who taught food-related areas at the high school level. Analysis of the FITA indicated a reliable instrument with 6 factors related to the following: the safety of food irradiation, learning about food irradiation, competence in teaching about it, perceived risk of foodborne illness from meat and fruits and vegetables, understanding of food irradiation, and knowledge about the topic.

Using this instrument, we found that these teachers held neutral to positive attitudes about the safety of irradiated foods, the perceived risk of foodborne illness, and learning about food irradiation. However, they held neutral to negative perceptions of their understanding of food irradiation as well as their competence to teach about it. Although some teachers may have had some understanding of food irradiation, as a whole, their knowledge about this technology seemed to be moderate. These results are supported by research conducted more than a decade ago indicating that family and consumer sciences professionals hold limited knowledge of food irradiation (Johnson 1990).

Our analyses suggested that educators' attitudes regarding the safety of food irradiation were positively correlated with their perceived understanding of food irradiation, knowledge of it, participation in previous food irradiation learning experiences, and their perceived competence to teach about it. This suggests the importance of providing opportunities for teachers to learn about the safety of food irradiation. These results are similar to previous research that indicated that educators' beliefs about the safety of food irradiation were influenced by their perceived understanding of it (Thompson and Knight 2006a).

Teachers' self-assessment regarding their Competence to teach food irradiation was strongly positively correlated with their understanding about it. Interestingly, teachers' perception of their knowledge and the safety of food irradiation seemed to be more important to Competence than other factors, including their actual knowledge about it. While we did not measure the amount of food irradiation education participants provided, due to their differing course offerings throughout the year, previous research has indicated that the attitudes of other family and consumer sciences professionals' regarding the safety of food irradiation, as well as their perceived understanding of it, can influence the amount of education they provide about it (Thompson and Knight 2006a). Therefore, based on these findings, professional development or education for teachers should provide opportunities for them to feel that they have an understanding not only of the technology but also of the related safety of food irradiation.

Correlation analysis also revealed important findings in terms of demographic and background factors. Unlike previous research (Fox 2002; Fox and others 2002; Nayga and others 2004; Thompson and Knight 2006), we found no correlation between teaching experience or educational level and attitudes toward food irradiation. However, unlike participants in consumer studies, most of the participants in our sample had earned at least a bachelor's degree. We were encouraged to find, however, that previous food irradiation training was positively correlated with teachers' attitudes toward the safety of food irradiation as well as their perceived understanding of it, indicating the potential impact of providing training to teachers in this area. Interestingly, teachers' knowledge was not correlated with previous training; however, our knowledge assessment consisted of only 6 items with low reliability and therefore may not have been a sensitive measure. Our results also indicated that previous training and interest in learning more about food safety technologies or food irradiation were not significantly correlated. Perhaps teachers who participated in previous educational opportunities felt they had an adequate understanding of food irradiation, therefore suggesting that education opportunities should be targeted to those who have had no training on the subject.

Limitations

Even though our study used randomly selected high school family and consumer sciences teachers, our results should be viewed with limited generalizability since our participants were from only 1 state and included only those teachers who taught Food and Nutrition Food Science and Technology, and/or Food Production Management and Services. Our sample did not include teachers with inaccessible e-mail addresses or nonrespondents; therefore, the generalizability of our results is limited. Although our response rate was near 60% (Moser and Kalton 1971; Bowling 1997), it is unknown if these results are representative of our entire population of teachers. Additional studies with teachers from other parts of the nation should be conducted to confirm the generalizability of our results. In addition, to increase the reliability of our instrument, additional items to assess Knowledge and other variables such as Understanding should be added in order to increase the reliability and validity of these factors.

Acknowledgment

This study was supported primarily through a grant from the U.S. Dept. of Agriculture (USDA-CSREES no. 2002-03935). The authors wish to thank the Family and Consumer Sciences Education Program Area of the Texas Educational Agency for its cooperation, and those Family and Consumer Sciences high school teachers who participated in the survey.

Ancillary