AOAC OMA# 2011.14 (Final Action Review)-OMB

2011.14 (Oct. 2018) – MTE-03 Final Action Review FOR ERP USE ONLY DO NOT DISTRIBUTE

and mix carefully. If the fat is not evenly dispersed, warm the test sample slowly in a water bath at 40°C, mix gently by inversion only, and cool quickly in the water bath at 20°C. ( 4 ) For dried milk, dried whey, and infant formula, transfer the test sample to a container with an airtight lid of twice the sample volume, close the container immediately, and mix by repeatedly shaking and inverting the container. ( 5 ) For cheese, remove the rind or surface layer so as to provide a test sample representative of the cheese as it is normally consumed. Grind the test sample with an appropriate device, mix the whole mass, and grind again quickly. If the test sample cannot be ground (e.g., soft cheese), mix the test sample thoroughly. ( 6 ) Transfer the homogenized sample to an airtight container immediately. Analyze test sample as soon as possible after homogenization. Do not analyze ground cheese that shows unwanted mold growth or deterioration. ( b ) Test portion preparation with MDC vessel .—( 1 ) Infant cereals or fortified milk powders .–Accurately weigh 0.50 ± 0.01 g test portion or sample mass on a dry weight basis in the prepared slurry to MDC vessel. ( 2 ) Milk and whey .–Weigh 4.0 g to the nearest 1 mg into the MDC vessel. ( 3 ) Dried milk, dried whey, and infant formula .–Weigh 0.5 g powdered product to the nearest 1 mg ) into the MDC vessel. [ Note : For infant formula, the test portion size is net 0.50 g of a powder sample, which should be taken from a reconstitution of 25 g powder in 200 g warm (50°C) water (e.g., 4.0 g of the reconstitution). ( 4 ) Cheese.– Weigh 0.5 – 0.8 g to the nearest 1 mg into the MDC vessel. ( 5 ) Butter .–Weigh 0.5 g to the nearest 1 mg into the MDC vessel. ( 6 ) Blank.– In parallel with test portion digestions and analyses, carryout a blank test using the same procedures and reagents. ( 7 ) Carefully add 5.0 ± 0.1 mL HNO 3 into MDC vessel. Loosely cap MDC vessel