EAL

MHFS: Food Safety (2012-2013)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

The purpose of this study is to develop an instrument that measures the general food safety performance associated with particular consumers. In order to do this, it is necessary to estimate the likelihood of specific food-handling practices being performed by different groups of consumers, identify which consumers are likely to engage in which safe or unsafe food-handling practices and understand how these different consumers differ from each other.

Inclusion Criteria:

Participants were asked to fill out the survey only if they prepared meals regularly (at least twice a week)
If they prepared meals less frequently, the addressee was asked to give the survey to the person who was most often responsible for meal preparation in the household
The survey was conducted by a professional market research agency and the sample was drawn from its existing panels.

Exclusion Criteria:

Not described.

Description of Study Protocol:

Recruitment

A postal questionnaire was sent to a representative sample of the Dutch population
The survey was conducted by a professional market research agency and the sample was drawn from its existing panels.

Design

Cross-sectional study.

Statistical Analysis

A principal component analysis (SPSS) was applied in order to investigate how many dimensions fitted the 55 resulting items
A confirmatory factor analysis (LISREL) confirmed that all 55 items could be mapped onto a single variable without causing unacceptable stress in the model [X² (1,430)=5,696, RMSEA=0.05]
To facilitate identification of factors that might determine cluster membership, significant differences in demographics (age, gender, education level, being employed, weekly duration of working hours, urbanization and psychological constructs) were applied as descriptive factors differentiating between the clusters using analysis of variance (ANOVA) for scale variables and X² statistics for dichotomous variables.

Data Collection Summary:

Timing of Measurements

Survey was mailed out to respondents one time.

Dependent Variables

Consumer food safety practices: The Rasch modeling technique was used to analyze the outcomes of several self-reported food safety practices
- The scoring of the Rasch model will have differential influences on the overall score
- The relevant parameters are estimated from the data. This results in a probabilistic outcome of the difficulty associated with each item and thresholds between the different categories of an item.
- Rasch scores were also used to determine participant clusters which may be linked to different risk groups
- To investigate food safety behavior, a list of 55 different food-handling practices was constructed
- Participants were asked to scale the items on a four-point scale labeled as never, sometimes, often and always
- Habit was measured by a 12-item self-reported index of habit strength with a seven-point Likert scale.

Independent Variables

Demographics

Age
Gender
Education level
Being employed
Weekly duration of working hours
Urbanization
Psychological constructs.

Description of Actual Data Sample:

Initial N: The original number mailed was not reported, but it was approximately 1,500: 1,044 valid responses were returned, with a reported response rate of 70%
Attrition (final N): 1,044 valid responses returned (65% female and 35% male)
Age: Range, 18 to 90 years
Ethnicity: Not described
Other relevant demographics: Not reported
Anthropometrics: Not reported
Location: Netherlands.

Summary of Results:

Key Findings

After cluster analysis, five segments of consumers were identified
A significant negative effect of age on the averaged scores of these two items was identified (R=0.19, P<0.001)
Different behaviors may have different effects on microbial growth in food and thus have different consequences for human health
Some potentially safe practices (e.g., use of meat thermometers) were reported as very difficult, while other safe practices were conducted by respondents more frequently (e.g., washing of fruit and vegetables)
People with open plan kitchens may find it difficult to prevent their pets (especially cats) from walking around the kitchen or even on top of the food preparation counter
From inspection of the cluster analysis, it can be seen that 59% of the participants always allow their pet into the kitchen, but never on the counter
The clusters all have significantly different means of the Rasch score (F(4,1039)2,751, P<0.001)
Cluster means as predictor for the Rasch score account for about 91% of the total variance.

Author Conclusion:

Modeling consumer behavior using Rasch modeling techniques provides a valuable contribution to the development of effective health and risk related interventions. In particular, the technique has potential to combine insights from the social and natural sciences in a multi-disciplinary effort to develop predictions of the health burden of different behaviors.
Once the microbial relevance of the different consumer behaviors has been confirmed by experiments and modeling, the scale developed in the research reported here can be used to develop risk communication targeted to the needs of different consumer groups, as well as to measure the efficacy of different interventions.

Funding Source:

Other:

Grant 014-12-033 from the Nutrition Health, Safety and Sustainability program of ZonMW the Netherlands

Reviewer Comments:

One limitation to this study is that the interpretation of the results is that data used to derive the Rasch scale are based on self-reported rather than observed behavior.

Quality Criteria Checklist: Primary Research
Relevance Questions
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	N/A
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	N/A

Validity Questions
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.3.	Were the target population and setting specified?	Yes
2.	Was the selection of study subjects/patients free from bias?		Yes
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	Yes
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	Yes
3.	Were study groups comparable?		Yes
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	Yes
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	Yes
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	Yes
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	Yes
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	Yes
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
4.	Was method of handling withdrawals described?		Yes
	4.1.	Were follow-up methods described and the same for all groups?	Yes
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	Yes
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	Yes
	4.4.	Were reasons for withdrawals similar across groups?	Yes
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
5.	Was blinding used to prevent introduction of bias?		N/A
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	N/A
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	N/A
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	N/A
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		Yes
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	N/A
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	Yes
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	N/A
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	Yes
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments described?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	Yes
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
7.	Were outcomes clearly defined and the measurements valid and reliable?		Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	Yes
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	Yes
	7.7.	Were the measurements conducted consistently across groups?	Yes
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	Yes
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	N/A
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	N/A
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes