The homogeneity of comminuted composites of 20 lb samples of apples, c
abbage, and green beans containing field-incurred residues of p,p'-met
hoxychlor was studied to determine whether a 5 min comminution in a 40
qt vertical cutter mixer produces a homogeneous composite and whether
the size of test portions used accurately represents the composite. D
uplicate test portions of 100, 50, 25, 10, 5, and 2 g taken from each
of 6 separate sections of the mixer were analyzed by standard pesticid
e residue methodology for p,p'-methoxychlor. Results of this study con
firmed that comminution of fresh produce in a 40 qt vertical cutter mi
xer, according to instructions described in the U.S. Food and Drug Adm
inistration's Pesticide. Analytical Manual, Volume I, section 203B, pr
oducer, a homogeneous composite, No significant differences were found
in the data for the 3 crops taken from the 6 sections of the mixer, T
est portion weights of 100, 50, and 25 g produced equivalent results f
or all 3 crops, Statistically significant differences were observed fo
r cabbage at 2, 5, and 10 g and for green beans at 2 g.