Variation of Microbial Contaminants in Classers' Raw Cottons

Abstract

The content of endotoxin, gram negative bacteria (GNB), gram positive bacteria (GPB) and fungi was determined for 296 classers' raw cottons derived from various U.S.A. growing areas in 1980. Levels of endotoxin varied from 0.01 to 83 ng per mg of raw cotton, while GNB counts covered the range from 5 to 2.3 X 105 colony forming units per mg. Tinged and spotted color groups contained higher levels of endotoxin than white grades. Significant differences between geographical regions were observed in the content of each microbial contaminant entrained in raw cotton. The Southwest and Southeast growing regions were characterized by raw cottons with the highest endotoxin levels. In general, Southwest raw cotton had the highest counts of GNB, GPB, and fungi, whereas cotton from the Farwest contained the lowest numbers of these same microorganisms.