Recommended procedures for preparation of analytical samples

Milk and cream. Immediately before withdrawing portions for analysis, bring the sample to ca. 20°C and mix thoroughly by agitation, taking care not to cause frothing, until a uniform emulsion forms. If the cream does not disperse, warm the sample slowly in a water bath to 30—40°C and mix until homogeneous. 

Unsweetened evaporated milk. Heat the unopened can in a 40—60°C water bath for 2h, shaking vigorously every 15min. Remove from bath, allow to cool to room temperature, open, and thoroughly stir the contents. 

Sweetened condensed milk. Heat the unopened can in a water bath at 30—40°C, open, remove entire contents and stir thoroughly until sample is homogeneous. 

Dried milk and nonfat dry milk. Transfer the sample to a dry, air-tight container with a capacity of ca. twice the volume of the sample and mix by shaking and inverting. Sift the sample through a 0.85 mm mesh sieve if necessary to break up any lumps and return it to the air-tight container. 

Butter and margarine. Soften the sample in a sampling container by warming in a water bath at as low a temperature as practicable, but not exceeding 39°C. Shake at frequent intervals during softening procedure, remove from bath, shake vigorously until the sample cools to a creamy consistency and promptly remove the sample for analysis. 

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