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Experiments with bracts and bract dusts.

Morey PR; Fischer JJ; Foarde KK; Attfield MD; Riffle D
Cotton dust: proceedings of the Ninth Cotton Dust Research Conference, beltwide cotton research conferences, January 9-11, 1985, New Orleans, Louisiana. Wakelyn PJ, Jacobs RR, eds. Memphis, TN: The National Cotton Council of America; 1985 Jan; :58-62
The contamination of dusts of cotton bracts and other plant parts with endotoxin and gram negative bacteria (GNB) was investigated. Bracts from cotton grown in North Carolina and Texas were collected before and after killing frosts. Plant parts were processed in a roller mill, sieved, and sorted into several dust fractions. Microbial contamination of raw ginned lint from semi closed and up land cotton, both grown in Texas, was also examined. For microbial analysis, plant materials were suspended in saline and plated out in growth media. Dusts from the North Carolina cotton bracts collected after a killing frost were contaminated with about 3 log orders more GNB and endotoxin than dusts of bracts collected in September. With bracts from the Texas cotton, senescent post freeze bract dusts were contaminated by concentrations exceeding 2 log orders of magnitude of endotoxin and GNB more than senescent pre freeze or green bract dusts. More endotoxin and greater numbers of GNB were found on senescent bract and pericarps when compared to leaf and green bract dusts. Dusts from pericarps collected before and after the first freeze contained comparable amounts of microbial contaminants. Semi closed cotton contained more than 2 times the amount of total botanical trash than up land cotton, and this trash was contaminated by more GNB and endotoxins than comparable trash present in up land lint. In addition, lint from semi closed cotton was more highly contaminated than lint from up land cotton. The authors conclude that microbial contamination of bracts increases after a killing frost. In addition, post freeze bracts are more friable and thus more easily rendered into respirable dust. Reduction of bract and other botanical trash components will result in development of a cleaner, higher quality cotton that will also contain smaller amounts of potential disease agents.
Quantitative-analysis; Dust-analysis; Industrial-dusts; Air-contamination; Airborne-particles; Occupational-respiratory-disease; Lung-irritants; Respiratory-irritants; Pathogens; Temperature-effects; Research
Publication Date
Document Type
Conference/Symposia Proceedings
Wakelyn PJ; Jacobs RR
Fiscal Year
Source Name
Cotton dust: proceedings of the Ninth Cotton Dust Research Conference, beltwide cotton research conferences, January 9-11, 1985, New Orleans, Louisiana
Page last reviewed: February 11, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division