Provision of chemical proficiency testing round on corn-based snack food for laboratories in the Asia-Pacific

As the only ISO/IEC 17043:2010-accredited food PT provider in the Philippines since 2013, the Department of Science and Technology-Food and Nutrition Research Institute successfully organized a PT Round on corn-based snack food for nutrition labeling parameters. The PT Round aimed at evaluating the performance of chemical laboratories in the Asia-Pacific area on the analysis of proximates (moisture, fat, protein and ash), total dietary fiber (TDF), saturated fatty acids and minerals (iron, calcium, sodium, potassium and zinc) in corn-based snack food through an interlaboratory comparison. A sufficiently homogeneous corn-based snack food test item was distributed to 67 registered laboratories. Results were evaluated using appropriate statistical procedures based on ISO 13528:2015. The mass fractions such as moisture, fat, protein, saturated fatty acids, calcium, sodium, potassium and zinc in corn-based snack food, which have x_pt with negligible uncertainties, i.e., u(x_pt) ≤ 0.3σ_pt, were issued with z scores, while other measurands with wide variability in the results, i.e., u(x_pt) > 0.3σ_pt, were issued with z′ scores. The x_pt (in % for proximates, TDF and saturated fatty acids, and 10^–5 g/g for minerals) and the percentage of laboratories that obtained “Satisfactory” performance (│z or z′ score│ ≤ 2) were: moisture (2.95, 88 %), fat (15.75, 91 %), protein (9.75, 69 %), ash (1.61, 64 %), TDF (5.04, 54 %), saturated fatty acid (5.90, 78 %), iron (2.93, 69 %), calcium (161, 74 %), sodium (139, 82 %), potassium (170, 77 %) and zinc (2.68, 85 %). This PT Round allowed to assess laboratories’ performances on the analysis of nutrition labeling parameters in corn-based snack food and improvement on performance by conducting investigative and corrective actions for those participants with “Warning” and “Action” signals.