Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2004
Publication Date: 10/1/2004
Citation: Byler, R.K. Cotton lint moisture-sample storage container comparison. Applied Engineering in Agriculture. Vol. 20(5): 543-546.
Interpretive Summary: The moisture content of cotton affects many aspects of the quality and dollar value during storage and processing. Gins go to considerable extent to control cotton moisture content by drying and adding moisture to lint. Several types of portable moisture meters are available but the standard for moisture content determination is to measure the weight of samples before and after they are dried in an oven. It is difficult to perform these tests in the field so samples are transported to laboratories experienced in running these tests. Traditionally these samples have been transported in quart metal cans, manufactured for use in the paint industry. These cans are reused but it is sometimes inconvenient to transport the cans for sample collection. This study was designed to compare samples stored in metal cans to similar samples stored in zipper closed plastic bags. Samples were conditioned to a moisture content of either 5.3% or 9.0% and placed in various containers, and stored in a room held at 53% and 22° C for 11 to 20 days. Several brands and types of zipper closure bags were included. Samples stored in metal cans gave the smallest change in moisture content. The brand of bag did not affect the moisture change. Double-bagging produced the lowest change of moisture content of the plastic bags tested. Therefore, metal cans should be used when available; however, if the samples are promptly shipped and analyzed then the double-bagged zipper closed plastic bags can be used. Samples should be tested within 7 days. Using this information will substantially improve validation of moisture levels in the cotton industry.
Technical Abstract: Quart size metal cans with metal lids have been used for transportation and storage of cotton lint samples intended for moisture content (mc) analysis by the oven method for many years. In some cases, particularly when the samples are collected at a distance from the analysis lab, the transportation of the empty cans can be inconvenient. This study examined the use of zipper-closed plastic bags, which are widely available, for sample transportation and storage. Cotton lint samples were preconditioned to higher and lower mc levels, placed in containers, and stored in an environment maintained at a constant relative humidity and temperature. The samples and containers were weighed periodically. After a period of between 11 and 20 days the cotton was tested for mc by the oven method. This mc was used with the weight data to calculate the mc over the storage period. Statistical analysis was used to estimate the mc-time slope based on the different containers. The metal cans proved to be the best of the containers tested. Double bagging using freezer bags was the best of the plastic bag containers. Therefore, metal cans should be used when available; however, if the samples are promptly shipped and analyzed then the double-bagged freezer bags can be used.