MATRIX UNCERTAINTY IN SUPPLEMENTED FOOD FOR ENUMERATION COLIFORMS ACCORDING TO ISO 19036:2019

Abstract

The analysis of 385 dietary supplement samples in liquid and powder forms, revealed a low contamination
rate of 2.34% (9 samples tested positive for coliforms). To enhance the accuracy and reliability of coliforms
quantification methods outlined in ISO 4832:2006, the study also established a measurement uncertainty
dataset for various sample matrices based on ISO 19036:2019. The study identified measurement
uncertainty data for four different matrices at three contamination levels (low, medium, and high), as
follows: umatrix for vitamin-fortified beverages (0.12 log10; 0.17 log10; 0.16 log10), umatrix for beverages
fortified with B vitamins and minerals (0.11 log10; 0.06 log10; 0.23 log10), umatrix for calcium-fortified oatmeal
(0.29 log10; 0.16 log10; 0.08 log10), and umatrix for probiotic-fortified milk powder (0.13 log10; 0.13 log10; 0.13
log10). These results offered critical insights for laboratories and enterprises to improve the precision and
efficiency of coliforms testing, supporting enhanced food quality and safety standards.