Extraction of light filth from unground marjoram: collaborative study.

The present method for filth in underground marjoram is conducted in 2 parts. The first of these, which is for heavy filth and sand, requires the spice to be boiled with petroleum ether, then floated off with chloroform and, if needed, carbon tetrachloride. The second part, which is for light filth, is dependent on completion of the heavy filth section. After the spice is air-dried, the light filth is extracted with heptane and water. The proposed method was developed to make light filth independent of heavy filth analysis, improve filth recoveries, and reduce microscopic examination time. The light filth is extracted by ethanol defatting followed by a combination 15-60% ethanol/mineral oil extraction in a Wildman trap flask. Tween 80-NaEDTA solution is added to the trapping system to reduce the rising of excess plant material to the trap interface. The official method (AOAC 13th edition secs 44.142, 44.120(b)) produced an average of 8 extraction papers per test portion and microscopic examination took an average of 88 min per test portion. The official method gave average recoveries of 14% for rodent hairs and 26% for insect fragments with 2 spike levels of 15 and 30 for each filth element. Recoveries of the 2 levels of each spike were not significantly different (P greater than 0.05). The proposed method gave average recoveries of 73% for rodent hairs and 70% for insect fragments. The proposed method has been adopted official first action to replace AOAC 13th edition secs 44.142 and 44.120(b) for unground marjoram only.