Decision flowchart for food classification by the extension and purpose of industrial processing: update and practical application

Abstract

Objective To describe the development and update of an instrument for food categorisation according to the extension and purpose of industrial processing, and to test its practical application. Methods After updating the instrument based on a recent publication on the NOVA classification, it was applied by five researchers to a database of 108 food items. These items are part of a database of foods announced in the health-related sections of supermarket promotional circulars. The Cohen’s weighted kappa coefficient was calculated to determine intra-rater agreement; Fleiss’ kappa and Kendall’s coefficient were applied to determine inter-rater agreement. Results In the updated version, two classes of additives and eight substances considered by the most recent publication as specific to ultra-processed foods were added. The intra-rater agreement was 100% (p<0.001), indicating an “almost perfect” agreement; Fleiss’ agreement among all raters ranged from 74% to 97% (p<0.001), which represents an agreement that ranged from “strong” to “almost perfect”; Kendall’s W was higher than 0.93 (p<0.001) among all raters. Conclusion The updated instrument showed high agreement and proved to be a methodologically sound and applicable tool for the purpose of classifying foods by the extension and purpose of industrial processing.