Development and psychometric evaluation of the halal food and nutrition literacy scale (HFNLS) in Turkish adults

Religious beliefs, particularly Islamic halal principles, influence food preferences and consumer behavior. This study highlights the global significance of halal certification and the halal industry. Furthermore, it aimed to clarify the definitions of halal food and nutrition literacy-terms that are not well-defined in the current literature, and to develop the Halal Food and Nutrition Literacy Scale (HFNLS) to assess this concept among Muslim adults. This methodological study was conducted in three stages: (1) literature review and item pool generation, (2) expert evaluation and optimization of items, and (3) psycometric evaluation. Data were collected through a web-based, interviewer-administered method. The study sample size consisted of 552 adults aged 20 years or older. An exploratory factor analysis (EFA) was conducted in 285 participants, and a confirmatory factor analysis (CFA) was performed using data from an independent sample of 267 Muslim adults. EFA yielded a 28-item scale with three dimensions that together explained 52.764% of the total variance. As a result of CFA, the fit indices showed an acceptable and near-good fit of the data to the hypothesized model (χ 2 /df = 2.657, p < 0.001, root mean square error of approximation (RMSEA) = 0.053, standardized root mean residual (SRMR) = 0.047, goodness-of-fit index (GFI) = 0.913, comparative fit index (CFI) = 0.927, incremental fit index (IFI) = 0.925, Tucker Lewis index (TLI) = 0.906, and normed fit index (NFI) = 0.880). The Cronbach’s alpha (α) coefficient was 0.917 for the total scale, indicating excellent internal consistency. The Cronbach’s α coefficients for each dimension exceeded 0.80. The developed HFNLS demonstrated satisfactory construct validity and high internal consistency as a multidimensional instrument for assessing halal food and nutrition literacy among Muslim adults. The three-factor structure identified by EFA was supported by CFA, indicating that functional, interactive, and critical literacy represent related but distinct dimensions of the construct. These findings support the use of the HFNLS in research and practice; however, further validation in culturally, geographically, and religiously diverse Muslim populations is warranted.