Extraction of light filth from barley, oatmeal, and mixed dry infant cereals: collaborative study.

A new method has been developed for the extraction of light filth from oatmeal, barley, and mixed dry infant cereals which involves HCl digestion followed by wet sieving. The residue is defatted in a paper cup, using isopropanol, and transferred to a 2 L Wildman trap flask with 40% isopropanol. Filth elements are extracted with light mineral oil. Interlaboratory studies resulted in 92 and 86% average recoveries of rodent hairs and insect fragments, respectively. The proposed method has been adopted as official first action.