Miller Magazine Issue: 125 May 2020

93 ARTICLE MILLER / MAY 2020 cultural commodities, which can lead to serious damage as a consequence of fungal activity (Fig. 2). This phenomenon is typical in particular of products transported in containers shipped overseas for relatively long journeys of several we- eks, and thus exposed to temperature fluctuations, especi- ally when the cargo is exposed to alternating warm and cool weather. The primary aim of our investigation was to study the occurrence of condensation. In addition, we investiga- ted the efficacy of calcium chloride in preventing moisture damage and a novel method based on a large bag named TranSafeliner (TSL) to reduce the intensity of condensation. MATERIALS AND METHODS Analysıs of condensatıon Four 20 ft metal containers (internal dimensions 2.43 m wide, 2.37 m high and 5.3 m long) were placed on the fore- court of a groundnut-processing plant at Kefar Saba, Israel. The containers were loaded with bags containing in-shell groundnuts with an average initial moisture content (mc) of 7.7% and 8.5 % for shelled and in-shell groundnuts, respe- ctively. The bags were positioned in layers of 30 bags each to form a stack to a height of six layers and raised on pallets. Thus each container contained 180 bags (about 5400 kg groundnuts). Calcıum chlorıde absorbıng capacıty To test the moistureabsorbing capacity, calcium chloride (technical grade) was placed (in lots of 4-5 kg) in plastic-co- ated cardboard boxes. The amounts of calcium chloride used were 30, 60 and 120 kg per container, while a fourth contai- ner without calcium chloride served as a control. The trial was carried out during October-November and lasted 3 weeks. Test of TranSafelıners (TSL) TranSafelinerTM is made of transparent multi-layer PE film of 100 microns thickness which has superior gas and moisture barrier properties. These liners fit in 20 ft and 40 ft container for bulk or bagged commodities. The TSLs are manufactured by GrainPro Inc. Of 7 containers, 3 contained cocoa beans inside TSLs, 3 contained a desiccant and in one container the cocoa bean stack was covered by ordinary PE liner providing non-her- metic conditions. The 7 containers were loaded in Ivory Co- Table 1. Average maximum and minimum temperatures recorded at different locations inside containers, and ambient temperature ( 0 C) Table 2. Average maximum and minimum relative humidities (%) recorded during the trial in the headspace and on the floor of the containers. ast and emptied after 55 days in Malaysia. The ship voyage took place during August-September 2019. RESULTS AND DISCUSSION In our trial, temperature gradients inside the containers were apparently initiated by daily ambient temperature flu- ctuations and the exposure of the containers to direct solar heating (Fig. 3). The r.h. of the air inside the containers and the mc of the groundnuts constituted sources of moisture which enhanced the condensation phenomenon. Table 1 shows that the extreme temperature fluctuation (from an average minimum of 16.4°C to a maximum of 39.4 °C), which can cause water condensation, took place near the roof. Indeed, when the temperature in the headspace of the containers was 39.4°C, the r.h. at the same location was Fig. 1- Shipping containers.