PARTIAL VALIDATION OF THE EFFECTS OF RE-ASHING DURATION AND COOLING TIME ON FOOD’S ASH DETERMINATION UNDER ISO/IEC 17025 GUIDELINES

Abstract

Validation of food analysis method is important to ensure results’ quality and it is a must in ISO/IEC 17025. A study was performed to evaluate effects of re-ashing duration and cooling time on food’s ash content. Proximate Food analysis (macro & micro nutrients) is very important. Methods were validated according to international guidelines (including ISO 17025) and through participation within international recognized proficiency schemes with adequate Z scores (− 2 ≥ x ≤ 2) and recoveries (90–110%). Many reported methods on ash analysis by dry ashing vary greatly in ashing conditions, making results incomparable. In the present study we validate re-ashing duration (1 & 2 hr) and cooling time (90 min/ RT) on ash measurement of 23 biscuits samples, 15 flour and 23 milk (infant formula) samples under ISO/IEC 17025 guidelines. For comparable results, a standardized method of re-ashing samples at specific °C is proposed for all types of foods (eg: biscuit, flour, infant formula, etc-----). Our results reveal that ashing and re-ashing at previous mentioned condition give comparable results with no significant change. This method was shown to have acceptable precision by the present study. This method was shown to have acceptable precision by the present study.