Food safety knowledge, attitudes and self-reported practices among Ontario high school students.

Majowicz, Shannon E. ; Diplock, Kenneth J. ; Leatherdale, Scott T. 等

Foodborne illness strikes an estimated one in eight Canadians annually. (1) Since such illnesses can be caused by mistakes in final food preparation and handling, (2,3) understanding the food safety-related knowledge, attitudes and practices of food handlers--both commercial and private--is key to identifying ways to minimize the risk of foodborne illness at the food handler step of the farm-to-fork continuum.

Youth and young adults represent a unique audience for interventions aimed at improving safe food handling and preparation. They are more likely to consume foods that pose a higher risk of foodborne illness than other ages; (4-7) they lack food preparation experience and food safety skills; (4,6,8,9) they are one of the groups most likely to mishandle food; (2) and they are less likely to read handling instructions for raw meat and poultry, (6) check refrigerator temperatures and know that processed meats should be refrigerated. (7) These risks are seriously compounded by this age group's high level of confidence in their ability to engage in safe food handling practices. (10)

High school youth are a group of particular interest. They are the age cohort (i.e., 14-18 years) immediately prior to the "second weaning" phenomenon, a hypothesized increase in foodborne illness that occurs when those in their early 20s are cooking for themselves for the first time. (11,12) They are also at an age when food preparation practices may not be fully established, such that appropriate teaching of safe food handling at this age may help instill lifetime safe food handling habits. (13,14)

There are few Canadian studies of knowledge, attitudes and practices related to food safety among individuals (4,15) and none that has assessed these aspects in high school individuals specifically. Therefore, our objective was to measure the food safety knowledge, attitudes and self-reported practices in a sample of high school students in the province of Ontario.

METHODS

We administered a school-wide, paper questionnaire to the student body of four Ontario high schools. We selected the four high schools from those (n = 79;2014-2015 school year) participating in an existing longitudinal study on youth health behaviours (the COMPASS study), which invites all schools from all passive consent school boards across Ontario to participate. (16) Using this established research platform enabled us to administer our survey school-wide to all students in grades 9 to 12 inclusive with consent to participate in the COMPASS study. COMPASS "consent to participate" rates for the four selected high schools ranged from 97% to 100% (Table 1). An insert was included in the COMPASS questionnaire and completed by students during class time on a date selected by the school, between mid-November and mid-December 2014. Schools were eligible to be selected for our questionnaire if they had in-school kitchen facilities, an enrolment circa 750 students and were within roughly two hours' driving distance of the University of Waterloo. Given average COMPASS survey completion rates of 80%, (17) we anticipated 2,400 survey participants. This study was reviewed and received ethics clearance through a University of Waterloo Research Ethics Committee.

We developed the survey by selecting questions from existing, validated questionnaires. (15,18-21) Because the survey was administered as an insert in a larger questionnaire, we prioritized key knowledge, attitude and self-reported practice questions that aligned with the Canadian Partnership for Consumer Food Safety Education's educational messages (i.e., cook, clean, chill, separate), as well as expectations of food and nutrition courses under the Ontario High School Curriculum. (22) In addition to demographic questions, the questionnaire (available on request) contained questions about food safety knowledge (four questions), attitudes (four questions) and frequency of self-reported practices (seven questions; Table 2).

The survey insert was Scantron-formatted and machine-scanned into an electronic database. We cleaned the data by cross-checking the consistency of answers within individuals, deleting any discrepant data. For some analyses, we grouped Likert-scale responses on agreement: "strongly agree" and "agree" responses were categorized as "agree", and "strongly disagree" and "disagree" responses were categorized as "disagree". Missing data for a given question were omitted from the analysis of that question.

Differences between means were tested using t-tests, with Duncan's pairwise comparison used to test differences between multiple means. Differences between proportions were tested using Pearson's chi-square test and Fisher's exact test if necessary. Factors associated with the number of correct knowledge items and correct answers for individual knowledge items were identified using multivariable Poisson and logistic regression respectively; for these models, school was included as a fixed effect, and clustering of students within schools was accounted for using the clustered sandwich estimator of variance, (23) to adjust for non-independence of students within schools. Analyses were conducted in Stata/SE 14.0 for Mac (StatCorp LP, College Station, Texas).

RESULTS

In total, 2,860 students completed the survey. Questionnaire completion rates per school were high and are shown, along with school-specific and overall respondent demographics, in Table 1. Respondents ranged from 13 to 18 years old, and all grades were represented. As expected, grade and age were highly correlated (R = 0.96);age was used instead of grade in all further analyses. Approximately 16.8% (480/2,860) of respondents worked or volunteered in a restaurant, deli or other food service location; 11.7% (336/2,860) in a daycare or other place where they interact with children; 4.9% (141/2,860) in a retirement home, nursing home or long-term care facility; and 2.6% (74/2,860) in a hospital.

Handling food for the public was not limited to respondents working or volunteering in a restaurant, deli or other food service location. Overall, 18% (514/2,860) of respondents reported currently handling food in commercial or public-serving venues (shown by school in Table 1); the proportion of students currently handling food was greatest for those in a food service location like a restaurant or deli (75.6%; 363/480), followed by a day care or other location for children (39.9%; 134/336), and a hospital (32.4%; 24/74). Of these students, less than half (45.1%; 232/514) had ever taken a course that taught them how to prepare food, such as a high-school food and nutrition class, or food handler certification. Previous food preparation courses were significantly less frequent among those not currently handling food in commercial or public-serving venues (32.5%;707/2,176) than those currently doing so (45.1%;232/514;p < 0.0001). Overall, 34.9% (939/2,690) of respondents had ever taken a course that taught them how to prepare food. As expected, respondents who had taken such a course or who currently handled food in commercial or public-serving venues reported more advanced abilities to cook from basic ingredients (Table 3).

Food safety knowledge among respondents was low. Half of the respondents (50.3%;1,439/2,860) correctly selected "keep foods refrigerated until it's time to cook or serve them" as the most important way to prevent food poisoning, but a third (34.1%; 975/2,860) selected "clean kitchen counters with sanitizing solutions weekly". Less than half (45.5%; 1,301/2,860) knew that the most hygienic way to wash hands required moistening them with water and using soap, but a quarter believed the most hygienic methods to be those using sanitizer only, no soap (24.3%;695/2,860). Of the 2,860 respondents, 17.3% (n = 496) knew that the best way to determine whether hamburgers were cooked enough was to measure the temperature with a food thermometer; over half (56.7%; 1,623/2,860) incorrectly believed that it was to cut the hamburger open and check the colour of the meat inside. The only knowledge item correct for the majority of respondents was knowing the definition of "microorganism" (72.8%;2,083/2,860).

Of the 2,860 respondents, 4.6% (n = 132) answered all four knowledge questions correctly, whereas 11.0% (n = 315) answered none correctly. The average number of correct responses was 1.86 (SD 1.05); when the average number was compared among schools in the bivariate analysis, the only significant difference was between School 2 and School 4 (p = 0.004;Table 1). Factors associated with the number of correct responses from the multivariable model are shown in Table 4. Specifically, adjusting for the other variables in the model, females had 1.08 (95% confidence interval [CI] 1.02, 1.13) times as many correct answers as males; those currently working or volunteering in a food service location (e.g., restaurant, deli) had 1.06 (95% CI 1.02, 1.12) times as many correct answers as those who did not work or volunteer in such locations; and for each additional year of age, respondents had 1.06 (95% CI 1.03, 1.09) times more correct answers. Respondents' school was also significantly associated with the number of correct answers. Factors associated with specific correct answers are shown in Table 5.

Over half the respondents agreed that they like learning about how to keep their foods safe to eat (57.4%; 1,562/2,721) and that they are concerned about getting food poisoning (52.7%; 1,425/ 2,706). A large majority (86.5%; 2,345/2,712) agreed that being able to cook safe, healthy meals is an important life skill, and 3.3% (89/2,712) disagreed. Most respondents were also confident that they could cook safe, healthy meals for themselves and their families, 72.7% (1,976/2,717) agreeing and 10.4% (283/2,717) disagreeing. Respondents' level of confidence was associated with the number of correct answers to the knowledge questions: those strongly disagreeing with the confidence statement averaged significantly fewer correct responses (1.43) than those who disagreed (2.01; p < 0.001), were neutral (1.82; p < 0.001), agreed (1.97; p < 0.001) or strongly agreed (1.84; p < 0.001) with the confidence statement. All other pairwise differences in the average number of correct responses by confidence level were not significant.

Respondents reported involvement in planning or helping to plan the meals in their household, with 10.6% (280/2,652) always, 25.5% (676/2,652) often, 34.2% (907/2,652) sometimes and 29.8% (789/2,652) rarely or never involved. Those who reported rarely or never being involved in meal planning were more likely to be male (odds ratio [OR]: 1.21; p = 0.037), older (OR: 1.09; p = 0.019), had a greater number of correct responses on the knowledge questions (OR: 1.13; p = 0.008), were less likely to be a current food handler (OR: 0.56; p = 0.001) and reported less advanced cooking abilities (OR: 0.53; p < 0.001), adjusting for school (p = 0.389) and whether the respondent worked or volunteered in a restaurant or other food service location (p = 0.798).

A majority of respondents reported always (56.1%; 1,480/2,638) or often (27.3%; 719/2,638) washing hands with soap and warm running water before preparing or handling food; 5.3% (141/2,638) reported rarely or never doing so. A majority of respondents also reported always (76.7%;1,898/2,476) or often (14.4%;356/2,476) washing hands with soap and warm running water after working with raw meat or chicken; 3.6% (89/2,476) reported rarely or never doing so. Providing a correct response to the hand washing knowledge question was not associated with reported hand washing frequency, adjusting for age and sex (data not shown). A majority of respondents reported always (65.8%;1,552/2,359) or often (19.5%;460/2,359) keeping raw meat or chicken away from ready-to-eat foods like raw vegetables; 5.7% (134/2,359) reported rarely or never doing so.

Respondents' use of ice packs in lunches was uncommon, with a majority rarely (14.0%; 333/2,375) or never (44.0%; 1,046/2,375) using ice packs when taking lunches to school and less than a third always (18.1%; 429/2,375) or often (10.4%; 246/2,375) doing so. Use of ice packs when taking lunch on day trips (e.g., track and field days) was more frequently reported, more than a third of respondents always (22.4%; 532/2,380) or often (15.4%; 367/2,380) doing so, but still 48.6% (1,157/2,380) reporting rarely or never doing so. Respondents' use of microwave ovens to cook or reheat meals was common, with a majority always (29.4%; 772/2,630) or often (37.3%; 981/2,630) doing so, and less than 10% rarely (6.1%; 161/2,630) or never (3.3%; 87/2,630) doing so.

DISCUSSION

We investigated key food safety knowledge, attitudes and self-reported practices in a sample of Ontario high school students. Here, one in five students reported currently handling food in a public-serving venue, but only half of these students had ever taken a course in which they were taught how to prepare food. This, together with low safe food handling knowledge and high self-reported confidence in the ability to prepare safe, healthy meals, suggests that high school students should be a key target population for safe food handling and hygiene education. The involvement in food service, low knowledge and high confidence observed here are consistent with other similar studies,4,6,8-10 supporting the need for additional targeted prevention support in this age group. One subgroup it may be particularly important to target is older, male high school students. Here, males had lower food safety knowledge than females (after adjustment for other factors), and older males were less likely to be involved in household meal planning than other students. Thus, this demographic may be a key subgroup to target for food safety education, and perhaps for food skills training in general.

With respect to both proper hand washing and ways to prevent foodborne disease, many students incorrectly selected options that involved sanitizers. Although this study did not explore the topic fully, choosing hand sanitizers as the best option within the hand hygiene continuum (i.e., as better than washing hands thoroughly with soap and running water) deserves further attention. This incorrect knowledge may be due to lack of exposure to proper hand and kitchen hygiene, either at home or through more structured education such as home economics courses or food handler certification, or it may be due to pervasive marketing of sanitizers in hand rubs, household cleaners and other products.

Knowing that use of a thermometer was the best way to check whether food was properly cooked was uncommon, although it was the only knowledge item positively associated with both currently handling food in a public-serving venue and with having previous training around food preparation and handling. Interestingly, food safety knowledge was most strongly associated with school and with age, the older students providing more correct answers, even after adjustment for sex, previous training and other factors. The reason for this is unknown, but it is possible that age is a proxy for food handling experience or acquisition of knowledge from sources not measured in this study.

Student use of ice packs in lunches and when taking food on day trips was infrequent. However, the circumstances surrounding ice pack use were not assessed, and it is unknown whether students were taking lunches containing foods that did not require ice packs, using other methods for keeping hot foods hot and cold foods cold, or were not using ice packs when they should have. Future research examining whether unsafe practices are occurring specific to bagged lunches may be warranted.

We found half the students surveyed always or often used a microwave oven to cook or reheat meals. Inadequate reheating poses a foodborne disease risk and may be an area of particular concern related to microwave use. (24) Additionally, processed foods, such as chicken nuggets and strips, can falsely appear precooked or ready to eat. (24,25) This, combined with our observation that the majority of students selected cutting food (in our survey, hamburgers) open as the best way to determine whether it is cooked enough to eat, may mean that particular attention should be paid to educating students about safe cooking with microwaves (e.g., food safety, burns), how to read labels to determine the raw or cooked state of processed food and how to use thermometers to determine doneness.

This study is subject to several limitations. First, because of limited page space and class time available for the survey, we prioritized the most important knowledge, attitude and practice questions. Future studies should more fully capture the range of important food safety knowledge and practices to better characterize the particular risks for this demographic. Additionally, we had limited information on school-level variables that might affect our results; here, school had a significant impact on knowledge, independently of other relevant factors, warranting further investigation into school-level influences. Another limitation is the use of self-reported practices. Most students reported always or often doing the correct behaviour. However, respondents typically overestimate or provide favourably biased reports of desired behaviours, (26-28) such that future studies measuring actual behaviours are needed to generate accurate estimates. A final limitation was the presence of missing data, which, although not extensive in our dataset, does have the potential to affect our results. We chose to omit missing data from the analysis, as is typical, but future efforts to characterize the nature and impacts of missing data are warranted.

In addition to the above limitations, we recognize that our results, drawn from four high schools, may have limited generalizability to other Ontario high school students, both within and outside of our study area. Study logistics limited data collection to schools within the Greater Golden Horseshoe and southwestern regions of Ontario, meaning that our findings may not be generalizable to other regions (e.g., northern Ontario), particularly if students' involvement in, and knowledge about, food preparation and food safety vary geographically. Given geographic variation in the types of food available and retail food environments, students in other geographic areas than ours may interact with food in substantially different ways, leading to different levels of knowledge, attitudes and behaviours. Our participating schools were in small towns (population < 40,000) surrounded by rural and agricultural areas, larger suburban areas (population > 120,000) and larger cities (population > 350,000), capturing a good range of urban and rural school environments. However, as stated, whether our results are representative of students outside our study schools is unclear.

In conclusion, these results show that high school students are an important group to target for safe food handling education, since work and volunteer opportunities put them in contact with both the public and food, and since food safety knowledge is low yet confidence is high. Older male students may be a subgroup who could particularly benefit. Additionally, instilling food safety behaviours at this age may be key to achieving proper food handling as youth transition into adulthood. Food safety is now explicit in food and nutrition courses in the Ontario 2013 Revised High School Curriculum; (22) however, these classes are electives that only reach some students. Given that youth employment in the accommodation and food service industry is increasing (29) and that the Government of Ontario encourages high school students to undertake food preparation activities as part of their mandatory 40 hours of volunteer work, for example "offer to cook dinner for an elderly, sick or just really-busy neighbor" or "[prepare] food at a shelter, crisis centre, seniors or community centre", (30) it is prudent to ensure that students engaging in such activities employ safe food handling, particularly when food is being prepared for vulnerable individuals. Interventions such as the food handler certification offered by local public health units and certified third-party private enterprises and the use of municipal bylaws requiring all food handlers be food safety certified may be additional ways to ensure that high school students practise safe food handling. However, evidence of the effectiveness of such educational activities, including the effectiveness in youth, is limited. Future studies should evaluate whether such education is an effective way to improve students' food safety knowledge and practice.

REFERENCES

(1.) Thomas MK, Murray R, Flockhart L, Pintar K, Pollari F, Fazil A, et al. Estimates of the burden of foodborne illness in Canada for 30 specified pathogens and unspecified agents circa 2006. Foodborne Pathog Dis 2013; 10(7):639-48. PMID: 23659355. doi: 10.1089/fpd.2012.1389.

(2.) Byrd-Bredbenner C, Berning J, Martin-Biggers J, Quick V. Food safety in home kitchens: A synthesis of the literature. Int J Environ Res Public Health 2013;10(9):4060-85. PMID: 24002725. doi: 10.3390/ijerph10094060.

(3.) Lee MB, Middleton D. Enteric illness in Ontario Canada, from 1997 to 2001. J Food Prot 2003;66(6):953-61. PMID: 12800994.

(4.) Nesbitt A, Majowicz SE, Finley R, Marshall B, Pollari F, Sargeant J, et al. High-risk food consumption and food safety practices in a Canadian community. J Food Prot 2009;7(12):2575-86. PMID: 20003742.

(5.) Byrd-Bredbenner C, Maurer J, Wheatley V, Schaffner D, Bruhn C, Blalock L. Food safety self-reported behaviors and cognitions of young adults: Results of a national study. J Food Prot 2007;70(8):1917-26. PMiD: 17803150.

(6.) Morrone M, Rathbun A. Health education and food safety behavior in the university setting. J Environ Health 2003;65(7):9-15. PMID: 12645419.

(7.) Unklesbay N, Sneed J, Toma R. College students' attitudes, practices, and knowledge of food safety. J Food Prot 1998;61(9):1175-80. PMID: 9766071.

(8.) Abbot JM, Policastro P, Bruhn C, Schaffner DW, Byrd-Bredbenner C. Development and evaluation of a university campus-based food safety media campaign for young adults. J Food Prot 2012;75(6):1117-24. PMID: 22691481. doi: 10.4315/0362-028X.JFP-11-506.

(9.) Haapala I, Probart C. Food safety knowledge perceptions, and behaviors among middle school students. J Nutr Educ Behav 2004;36(2):71-76. PMID: 15068755. doi: 10.1016/S1499-4046(06)60136-X.

(10.) Stein SE, Dirks BP, Quinlan JJ. Assessing and addressing safe food handling knowledge attitudes, and behaviors of college undergraduates. J Food Sci Educ 2010;9:47-52. doi: 10.1111/j.1541-4329.2010.00092.x.

(11.) Majowicz SE, Dore K, Flint JA, Edge V, Read S, Buffett C, et al. Magnitude and distribution of acute self-reported gastrointestinal illness in a Canadian community. Epidemiol Infect 2004;132(4):607-17. PMID: 15310162. doi: 10.1017/S0950268804002353.

(12.) Waltner-Toews D. Food, Sex, and Salmonella: Why our Food is Making Us Sick. Vancouver, BC: First Greystone Books 2008 edition.

(13.) Eves A, Bielby G, Egan B, Lumbers ML, Raats MM, Adams MR. Food hygiene knowledge and self-reported behaviours of UK school children (4-14 years). Br Food J 2006;108(9):706-20. doi: 10.1108/00070700610688359.

(14.) Fischer ARH, Frewer LJ, Nauta MJ. Toward improving food safety in the domestic environment: A multi-item Rasch scale for the measurement of the safety efficacy of domestic food handling practices. Risk Anal 2006; 26(5):1323-38. PMID: 17054534.

(15.) Rebellato S, Cholewa S, Chow J, Poon D. Impact of PROTON a food handler certification course on food handlers' knowledge, attitudes and behaviours. J Food Safety 2011;32(1):129-33. doi: 10.1111/j.1745-4565.2011.00359.x.

(16.) Leatherdale ST, Brown KS, Carson V, Childs RA, Dubin JA, Elliott SJ, et al. The COMPASS study: A longitudinal hierarchical research platform for evaluating natural experiments related to changes in school- level programs policies and built environment resources. BMC Public Health 2014;14:331. PMID: 24712314. doi: 10.1186/1471-2458-14-331.

(17.) Leatherdale ST, Cole A. Examining the impact of changes in school tobacco control policies and programs on current smoking and susceptibility to future smoking among youth in the first two years of the COMPASS study: looking back to move forward. Tob Induc Dis 2015;13(1):8. PMID: 25834482. doi: 10.1186/s12971-015-0031-1.

(18.) Yarrow L, Remig VM, Higgins MM. Food safety educational intervention positively influences college students' food safety attitudes beliefs, knowledge, and self-reported practices. J Environ Health 2009;71(6):30-35. PMID: 19192742.

(19.) Lynch RA, Steen MD, Pritchard TJ, Buzzell PR, Pintauro SJ. Delivering food safety education to middle school students using a web-based, interactive, multimedia, computer program. J Food Sci Educ 2008;7(2):35-42. doi: 10.1111/j.1541-4329.2007.00046.x.

(20.) Byrd-Bredbenner C, Wheately V, Schaffner D, Bruhn C, Blalock L, Maurer J. Development and implementation of a food safety knowledge instrument. J Food Sci Educ 2007;6(3):46-55. doi: 10.1111/j.1541-4329.2007.00029.x.

(21.) Byrd-Bredbenner C, Wheatley V, Schaffner D, Bruhn C, Blalock L, Maurer J. Development of food safety psychosocial questionnaires for young adults. J Food Sci Educ 2007;6(2):30-37. doi: 10.1111/j.1541-4329.2007.00021.x.

(22.) Government of Ontario. The Ontario Curriculum Grades 9 to 12: Social Sciences and Humanities. 2013 (revised).

(23.) Rogers WH. Regression standard errors in clustered samples. In: Stata Technical Bulletin 13:19-23. Reprinted in Stata Technical Bulletin Reprints. College Station TX: Stata Press 1993, vol. 3, pp. 88-94.

(24.) Mody RK, Meyer S, Trees E, White PL, Nguyen T, Sowadsky R, et al. Outbreak of Salmonella enterica serotype I 4,5,12:i:- infections: The challenges of hypothesis generation and microwave cooking. Epidemiol Infect 2014;142(5):1050-60. PMID: 23916064. doi: 10.1017/S0950268813001787.

(25.) Currie A, MacDougall L, Aramini J, Gaulin C, Ahmed R, Isaacs S. Frozen chicken nuggets and strips and eggs are leading risk factors for Salmonella Heidelberg infections in Canada. Epidemiol Infect 2005;133(5):809-16. PMID: 16181499.

(26.) Abbot JM, Byrd-Bredbenner C, Schaffner D, Bruhn CM, Blalock L. Comparison of food safety cognitions and self-reported food-handling behaviors with observed food safety behaviors of young adults. Eur J Clin Nutr 2009;63(4):572-79. PMID: 18000516.

(27.) Kendall PA, Elsbernd A, Sinclair K, Schroeder M, Chen G, Bergmann V, et al. Observation versus self-report: validation of a consumer food behavior questionnaire. J Food Prot 2004; 67(11):2578-86. PMID: 15553645.

(28.) Redmond EC, Griffith CJ. A comparison and evaluation of research methods used in consumer food safety studies. Int Journal Consumer Studies 2003;27(1):17-33. doi: 10.1046/j.1470-6431.2003.00283.x.

(29.) Service Canada. Client Segment Profile Youth Aged 15 to 29, Ontario. April 2014.

(30.) Government of Ontario. YOUTHCONNECT.CA. Available at: http://youthconnect.ca/htdocs/english/getinvolved/what.asp#food (Accessed June 25, 2015).

Received: July 6, 2015

Accepted: November 5, 2015

Shannon E. Majowicz, PhD, [1] Kenneth J. Diplock, MHS CIPHI(C), [1,2] Scott T. Leatherdale, PhD, [1] Chad T. Bredin, BA, [3] Steven Rebellato, PhD, [1] David Hammond, PhD, [1] Andria Jones-Bitton, DVM PhD, [4] Joel A. Dubin, PhD [1,5]

[1.] School of Public Health and Health Systems, University of Waterloo, Waterloo, ON

[2.] School of Health and Life Sciences and Community Services, Conestoga College Institute of Technology and Advanced Learning, Kitchener, ON

[3.] Propel Centre for Population Health Impact, University of Waterloo, Waterloo, ON

[4.] Department of Population Medicine, University of Guelph, Guelph, ON

[5.] Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, ON

Correspondence: Shannon Majowicz, PhD, School of Public Health and Health Systems, University of Waterloo, 200 University Ave. West, Waterloo, ON N2L 3G1, Tel: 519-888-4567, ext. 31790, E-mail: smajowicz@uwaterloo.ca

Acknowledgements: The authors thank the students and staff of the participating schools for their support of this study. Andrew Papadopoulos (University of Guelph) contributed to early ideas for this work. The research was funded by the Ontario Ministry of Agriculture, Food and Rural Affairs' Food Safety Research Program (FS2013-1843; grant awarded to S. Majowicz). The research built off an existing research platform (COMPASS) supported by a bridge grant from the Canadian Institutes of Health Research (CIHR) Institute of Nutrition, Metabolism and Diabetes (INMD) through the "Obesity--Interventions to Prevent or Treat" priority funding awards (OOP-110788; grant awarded to S. Leatherdale) and an operating grant from the CIHR Institute of Population and Public Health (IPPH) (MOP-114875; grant awarded to S. Leatherdale). Drs. Leatherdale and Hammond are Chairs in Applied Public Health, funded by the Public Health Agency of Canada (PHAC) in partnership with CIHR Institute of Neurosciences, Mental Health and Addiction (InMhA) and IPPH.

Conflict of Interest: None to declare.

Table 1. Survey completion rates and demographic
characteristics of survey respondents

                                School 1          School 2

Proportion of whole school        100%              100%
  participating in the
  COMPASS
Study
Survey completion rate       78.5% (766/976)   80.6% (701/870)
  (no. of survey
  respondents/total school
  enrolment)
Mean age in years (SD)         15.2 (1.13)       15.8 (1.34)
% female                          54.0              51.2
% grade
    9                             29.8              19.2
    10                            31.5              22.6
    11                            20.5              24.2
    12                            18.2              34.0
% currently handling food,        14.9              20.7
  as an employee or
  volunteer, in commercial
  or public-serving venues
% who had ever taken a            30.9              49.8
  course that taught them
  how to prepare food
Mean no. correct food          1.84 (1.00)       1.77 (1.14)
  safety answers out of
  four (SD)

                                School 3           School 4

Proportion of whole school        98.7%             97.4%
  participating in the
  COMPASS
Study
Survey completion rate       75.3% (488/648)   80.6% (905/1123)
  (no. of survey
  respondents/total school
  enrolment)
Mean age in years (SD)         15.5 (1.20)       15.6 (1.18)
% female                          51.7               53.2
% grade
    9                             21.8               21.3
    10                            28.6               23.7
    11                            25.3               26.0
    12                            24.3               29.0
% currently handling food,        24.2               15.1
  as an employee or
  volunteer, in commercial
  or public-serving venues
% who had ever taken a            30.5               29.2
  course that taught them
  how to prepare food
Mean no. correct food          1.88 (1.08)       1.93 (1.00)
  safety answers out of
  four (SD)

                                   Total

Proportion of whole school          --
  participating in the
  COMPASS
Study
Survey completion rate       79.1% (2860/3617)
  (no. of survey
  respondents/total school
  enrolment)
Mean age in years (SD)          15.5 (1.23)
% female                           52.7
% grade
    9                              23.1
    10                             26.4
    11                             24.0
    12                             26.5
% currently handling food,         18.0
  as an employee or
  volunteer, in commercial
  or public-serving venues
% who had ever taken a             34.9
  course that taught them
  how to prepare food
Mean no. correct food           1.86 (1.05)
  safety answers out of
  four (SD)

Table 2. Food safety knowledge, attitude and self-reported
practice questions included in the survey

Question                               Format

"Which is the most hygienic way to     Multiple choice
wash your hands?"

1 = Apply sanitizer, run water, rub
hands together for 20 seconds,
rinse hands, dry hands, rub on an
antiseptic hand lotion

2 = Apply soap, rub hands together
for 20 seconds, rinse hands under
water, dry hands, apply sanitizer

3 = Run water, moisten hands, apply
soap, rub hands together for 20
seconds, rinse hands, dry hands *

4 = Run water, moisten hands, apply
sanitizer, rub hands together for
20 seconds, rinse hands, dry hands,
rub on antiseptic hand lotion

"Which of the following is
considered the most important way
to prevent food poisoning?"

1 = Spray for pests in the kitchen
area at least every week

2 = Rarely or never serve leftovers

3 = Keep foods refrigerated until
it's time to cook or serve them*

4 = Clean kitchen counters with
sanitizing solutions weekly

"Which method is the best way to
determine whether hamburgers are
cooked enough to eat?"

1 = Cut one to check the colour of
the meat inside

2 = Check the colour of the juice
to be sure it is not pink

3 = Measure the temperature with a
food thermometer *

4 = Check the texture or firmness
of the meat

5 = Measure the length of time the
hamburgers cook

"What are microorganisms?"

1 = Poisons that can contaminate
our food and water

2 = Small living things that are
too small to be seen with our eyes *

3 = Small insects that we can see

4 = Large bugs that can land on our
food and surfaces

"I like learning about how to keep     5-point Likert
my foods safe to eat."                 scale ("strongly
                                       agree" to
"I am concerned about getting food     strongly
poisoning."                            disagree)

"I am confident that I can cook
safe, healthy meals for myself and
my family."

"Being able to cook safe, healthy
meals is an important life skill."

"I plan, or help plan, the meals in    5-point Likert
my household."                         scale ("always"
                                       to "never")
"Before preparing or handling food,
I wash my hands with soap and warm
running water."

"I wash my hands with soap and warm
running water after working with
raw meat or chicken."

"I keep raw meat and chicken away
from ready-to-eat foods like raw
vegetables."

"I use an ice pack when I take my
lunch to school."

"I use an ice pack when I take my
lunch with me for day trips (like a
track and field day)."

"When I cook or reheat meals, I use
a microwave."

* Correct responses to multiple choice knowledge questions.

Table 3. Self-described ability to cook
from basic ingredients among Ontario
high school students, by whether they a)
currently handle food in commercial or
public-serving venues * or b) had ever
taken a course ([dagger]) that taught them to
prepare food

                                      Percentage of students

                         Neither        Currently        Previous
                         previous     handling food    training only
                       training nor   only (n = 276)     (n = 692)
                       current food
                         handling
                        (n = 1437)

"I don't know how to        7.4             4.7             2.6
cook."

"I can only cook           14.0             5.8             7.1
food when the
instructions are on
the box (like Kraft
Dinner[R])."

"I can do the basics       21.9            14.1            13.5
from scratch (like
boil an egg or make
a grilled cheese
sandwich) but
nothing more
complicated."

"I can prepare             41.7            48.9            48.8
simple meals if I
have a recipe to
follow."

"I can cook almost         15.0            26.5            28.0
anything."

                          Percentage of students

                         Both previous        All
                          training and      students
                       currently handling
                         food (n = 226)

"I don't know how to           5.3             5.7
cook."

"I can only cook               5.3            10.4
food when the
instructions are on
the box (like Kraft
Dinner[R])."

"I can do the basics          11.1            17.9
from scratch (like
boil an egg or make
a grilled cheese
sandwich) but
nothing more
complicated."

"I can prepare                41.1            44.4
simple meals if I
have a recipe to
follow."

"I can cook almost            37.2            21.6
anything."

* Including working or volunteering in a
food service location, hospital,
retirement home, long-term care
facility, day care or other location for
children.

([dagger]) Including high school food
and nutrition classes and food handler
certification.

Table 4. Factors associated with the number of correct
answers to the food safety knowledge multiple
choice questions, with significant factors shown
in bold

                              Poisson     95% confidence
                            regression       interval
                            coefficient

Age                            0.061#      0.033#, 0.089#
Sex                            0.073#     -0.122#, -0.024#
School 1 *                     0.054#      0.032#, 0.076#
School 3 *                     0.048#      0.035#, 0.061#
School 4 *                     0.098#      0.083#, 0.113#
Currently handle               0.030      -0.003, 0.064
  food in a commercial
  or public-serving
  venue ([dagger])
Had ever taken a course       -0.009      -0.066, 0.048
  ([double dagger])
  that taught them to
  prepare food
Currently work or              0.062#      0.018#, 0.106#
  volunteer in a
  restaurant, deli or
  other food service
  location
Currently work or             -0.182      -0.365, 0.006
  volunteer in a hospital

* School 2 is the referent group.

([dagger]) Including working or volunteering in a food-service
location, hospital, retirement home, long-term care facility,
day care or other location for children.

([double dagger]) Including high school food and nutrition classes
and food handler certification.

Note: Significant factors indicated with #.

Table 5. Odds ratios (with 95% confidence intervals) for factors
associated with correctly answering the individual food safety
knowledge multiple choice questions, with significant factors
shown in bold

                         Selecting the most      Selecting the most
                           hygienic way to        important way to
                             wash hands             prevent food
                                                      poisoning

Age                     1.075 (1.030, 1.122)#   1.100 (1.075, 1.127)#
Sex                     0.691 (0.630, 0.757)#   0.970 (0.740, 1.273)
School 1 *              1.104 (1.049, 1.164)#   1.229 (1.199, 1.259)#
School 3 *              0.972 (0.939, 1.007)    1.215 (1.175, 1.256)#
School 4 *              1.216 (1.157, 1.278)#   1.399 (1.353, 1.448)#
Currently handle food   0.999 (0.738, 1.351)    1.035 (0.812, 1.319)
  in a commercial or
  public-serving
  venue ([dagger])
Had ever taken a        0.926 (0.762, 1.126)    0.882 (0.752, 1.034)
  course ([double
  dagger]) that
  taught them to
  prepare food
Currently work or       1.102 (0.935, 1.300)    1.213 (0.989, 1.488)
  volunteer in a
  restaurant, deli
  or other food
  service location
Currently work or       0.801 (0.468, 1.372)    0.645 (0.357, 1.163)
  volunteer in a
  hospital

                         Selecting the best         Selecting the
                        way to determine that    correct definition
                        hamburgers are cooked    of "microorganisms"
                            enough to eat

Age                     1.235 (1.027, 1.485)#   1.260 (1.202, 1.320)#
Sex                     0.806 (0.537, 1.210)    0.952 (0.749, 1.208)
School 1 *              0.645 (0.609, 0.772)#   1.488 (1.453, 1.523)#
School 3 *              1.058 (0.939, 1.193)    1.223 (1.167, 1.282)#
School 4 *              0.689 (0.624, 0.761)#   1.777 (1.746, 1.809)#
Currently handle food   1.486 (1.205, 1.833)#   0.931 (0.641, 1.351)
  in a commercial or
  public-serving
  venue ([dagger])
Had ever taken a        1.755 (1.057, 2.914)#   0.761 (0.619, 0.936)#
  course ([double
  dagger]) that
  taught them to
  prepare food
Currently work or       1.382 (0.955, 1.999)    0.981 (0.882, 1.092)
  volunteer in a
  restaurant, deli
  or other food
  service location
Currently work or       1.189 (0.634, 2.070)    0.411 (0.310, 0.545)#
  volunteer in a
  hospital

* School 2 is the referent group.

([dagger]) Including working or volunteering in a food service
location, hospital, retirement home, long-term care facility,
day care or other location for children.

([double dagger]) Including high school food and nutrition
classes and food handler certification.

Note: Significant factors are indicated with #.