Results of the eurofoods trial on between-laboratory variation in the analysis of macronutrients in foods

In order to determine the influence of laboratory procedures on nutrient values in different food tables and data banks, an interlaboratory study was set up. Nineteen laboratories participated, and received well-homogenized samples of egg powder, full-fat milk powder, whole rye and wheat meal, biscuits and french beans to perform analyses of macronutrients by their own routine methods. For dry weight the results agreed very well; the results for ash agreed rather well. For protein the coefficient of variation between laboratories (CVbetween) ranged from 2.8% to 6.4%. The CVbetween for total fat ranged from 5.4% to 54%. For available carbohydrates the CVbetween ranged from 9% to 27%. The CVbetween for total dietary fiber ranged from 23% to 84%. It is concluded that leading laboratories produce widely different values for macronutrients in common foods. Reference materials of certified nutrient concentration are needed.