HIGH MOISTURE STORAGE EFFECTS ON MICROBIAL POPULATIONS AND COTTON DUST GENERATION POTENTIAL

Authors: Chun, David; Brushwood, Donald

Submitted to: Textile Research Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/20/1999
Publication Date: N/A
Citation: Chun, D.T., Brushwood, D.E. 1999. High moisture storage effects on microbial populations and cotton dust generation potential. Textile Research Journal 69 (9)642-648.

Interpretive Summary: This study was divided into two parts: water alone and then high moisture only for a worst case situation. In the high moisture study urea and ammonia were used to attempt inhibition of the effects of microbial activity to see if we could get the benefits of water to reduce stickiness without the detrimental microbial aspects. At each time interval, each moisture content cottons were removed and assayed for microbial population, color, strength, sugar content, thermal detector stickiness determination, and cotton dust potential. Cotton dust potential was determined with the Microdust & Trash Monitor. Increased microbial populations was observed with cottons stored under higher moisture contents. Over the same storage time, cotton dust potential increased and the greater increases occurred with the wetter cottons. When moist cotton is treated with high levels of ammonia before storage, fungal and Gram-negative bacterial populations did not increase during storage and was at levels lower than the ambient moisture cottons. While the cotton dust potential was higher with the 30% moisture content cottons than the ambient control cottons, the same cottons which were treated with high levels of ammonia had the same cotton dust potential as ambient moisture content levels. This along with the reduced Gram-negative population suggests that ammonia may help control development of endotoxin potential in wet stored cottons which may lead to an actual reduced airborne endotoxin load potential.

Technical Abstract: The feasibility of using high cotton moisture content during storage to reduce cotton stickiness was studied. Initially, water alone at the moisture contents if 15%, 30% and 40% moisture was used. The cottons were stored for 5, 11 and 15 days at 10 C. A second set of cottons were brought to 30% moisture using water augmented with urea or ammonia to minimize microbial effects. The cottons were stored for 15 days at room temperature. Microbial population, cotton quality (strength and color), cotton stickiness, and cotton dust potential were determined. Increased microbial populations was observed with cottons stored under higher moisture contents than with ambient moisture content cottons. Over the same storage time, cotton dust potential increased and the greater increases occurred with the wetter cottons. However, when moist cotton is treated with high levels of ammonia before storage, fungal and Gram-negative bacterial populations did not increase during storage and was at levels lower than the ambient moisture cottons. While the cotton dust potential was higher with the 30% moisture content cottons than the ambient control cottons, the 30% moisture content cottons treated with high levels of ammonia had the same cotton dust potential as ambient moisture content levels. This along with the reduced Gram-negative population suggests that ammonia may help as a preventative control in keeping endotoxin potential from increasing in wet stored cottons.