POST HARVEST MEASUREMENT AND MANAGEMENT SYSTEMS TO IMPROVE PEANUT QUALITY AND US COMPETITIVENESS
Location: Peanut Research
Title: Environmental Conditions During Transport of Shelled Peanuts in Overseas Containers
Submitted to: American Peanut Research and Education Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 12, 2007
Publication Date: January 9, 2008
Citation: Butts, C.L., Dorner, J.W., Sobolev, V., Sanders, T.H., Whitaker, T.B. 2008. Environmental Conditions During Transport of Shelled Peanuts in Overseas Containers. American Peanut Research and Education Society Abstracts.
Interpretive Summary: none required.
Peanuts exported overseas may be in transit from the shelling plant or cold storage to the overseas manufacturer for 30 d or more. In some instances, quality assurance testing at the overseas destination indicates that peanuts no longer meet contractual quality specifications. Considerable effort and research have been devoted to developing standard sampling and testing protocols for various quality specifications such as aflatoxin contamination in shelled peanuts. A study was undertaken to monitor the temperature and relative humidity conditions in shelled peanuts during transit overseas. Dataloggers (Hobo H08-003-02, Onset Computers, Bourne, MA) were placed in small sample bags with approximately 1 kg of shelled peanuts to record temperature and relative humidity. Three samples with dataloggers were placed in a 1-t unit of shelled peanuts; one at the center, one at the outside edge, and one at the top. The 1-t unit consisted of shelled peanuts in a tote or a pallet of 25 jute bags. Each overseas container held 22 units, five of which were instrumented. Two dataloggers were installed in the headspace of each container to record the temperature and humidity. A total of two containers were shipped between August 2005 and October 2005 through the port at Savannah, GA to Rotterdam, Netherlands. The samples were retrieved from each unit with the datalogger upon unloading at the destination and returned to the US via overnight courier for analysis. Peanut samples were oil roasted and blanched then visually inspected for spotting. Data for percent spotted peanuts before and after shipment were compared.
Shipment 1 contained peanuts contained peanuts packaged in totes and jute bags on pallets. Peanuts were packaged on August 16, 2005 and placed in dry storage. Peanuts were removed from dry storage, placed in containers, and shipped on August 18, 2005. The container arrived at it destination in Rotterdam on September 23, 2005. Total transit time from Headland, AL to Rotterdam was 36 d (864 h). Based on subsequent research in which peanuts were stored at 21 C and 76% relative humidity, spot percentage would be expected to increase above a 2% threshold in about 21 d (504 h). Only one sensor recorded conditions greater than 21 C and 76 % relative humidity for any significant amount of time. The sensor placed in the top of one tote accumulated 59 h above the threshold. Spot percentage did not increase significantly in the first shipment.
Shipment 2 contained peanuts from the same shelled stock lot as Shipment 1. These peanuts were placed in cold storage on August 16, 2005. The peanuts were removed from cold storage and immediately placed in containers on August 26, 2005. The container arrived at its destination in Rotterdam on October 7, 2005 for a total transit time including cold storage of 52 d (1248 h). Percent spots increased from 1.2 to 2.5% during transit. However, using the same temperature and humidity criteria, only 12 h were accumulated above the threshold in one sample out of 15.
In both shipments, conditions were very stable while in transit on the ship because the containers were placed below deck. The temperature conditions in the headspace were not subject to significant diurnal fluctuations. However, once the containers arrived at the European port, diurnal fluctuations in temperature and relative humidity occurred. The containers remained unopened at the port for several days. During this time, the relative humidity remained above 75% for a significant portion of the time. Had the temperature been higher, the conditions could have been conducive for fungal activity.