THE DEVELOPMENT AND EVALUATION OF SECONDARY FOOD REFERENCE MATERIALS FOR THE DETERMINATION OF CHOLESTEROL, FATTY-ACIDS AND SELECTED WATER-SOLUBLE VITAMINS IN FOODS

The suitability of a number of 'off-the-shelf' food items for use as s econdary reference materials for incorporation into routine work batch es to enhance quality assurance has been evaluated over a 5 month peri od. The commodities were canned ham (tested for cholesterol and fatty acids), wheat germ (tested for fatty acids, thiamine, riboflavin and n iacin), two fish oils (tested for fatty acids) and powdered orange dri nk vitamin C supplement (tested for ascorbic acid). Foods were purchas ed locally and analysed using recognized methods. Seven replicate anal yses were performed initially on each food to establish homogeneity, w ith subsequent analyses in triplicate. Overall mean results (+/-2 s.d. ) for the 5 month study were as follows: cholesterol in canned ham, 65 +/- 7.2 mg/100 g; thiamine in wheatgerm, 1.97 +/- 0.26 mg/100 g; ribo flavin in wheatgerm, 0.27 +/- 0.17 mg/100 g; niacin in wheatgerm, 7.1 +/- 0.9 mg/100 g; ascorbic acid in vitamin C supplement, 718 +/- 70 mg /100 g; C18:0, C18:1 and C18:2 in wheatgerm, 0.72 +/- 0.11, 15.2 +/- 0 .5 and 57.7 +/- 1.4% total fatty acids respectively; C18:0, C18:1 and C18:3 in canned ham, 12.5 +/- 0.6, 44.7 +/- 1.4 and 0.57 +/- 0.12% tot al fatty acids respectively; C18:0, C20:5 and C22:6 in cod liver oil, 2.4 +/- 0.1, 12.6 +/- 1.2, and 5.6 +/- 0.8% total fatty acids respecti vely; C18:0, C20:5 and C22:6 in omega 3 fish oil, 3.7 +/- 0.2, 19.2 +/ - 0.5, and 12.8 +/- 1.4% total fatty acids, respectively. Statistical data were obtained from the multiple analyses, and based on the data g enerated, the foods tested were shown to have satisfactory homogeneity and stability for use as secondary reference materials over an extend ed period. Copyright (C) 1996 Elsevier Science Ltd.