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Multi-distributed wireless sensors for monitoring a long distance transport of lemons in a reefer container

Research Areas
  • Foodstuffs tecnology,
  • Agriculture,
  • Engineering

The study of the temperature gradients in cold stores and containers is a critical issue in the food industry for the quality assurance of the products during transport and for minimizing losses. This work presents an analysis of the temperatures during the refrigerated transport of 17000kg of lemons in a reefer (set point temperature at 4ºC) on container ship from Montevideo (Uruguay) to Cartagena (Spain). The monitoring was performed by using two sensor technologies for temperature: semi-passive RFID loggers (TurboTag cards), and iButton loggers with 1-Wire® electrical interface. The objective is to carry out a multi-distributed supervision by low-cost, wireless and autonomous sensors for the characterization of the distribution and spatial gradients of temperatures during a long distance transport. 39 TurboTag and 13 ibutton were distributed in a 40'High-Cube standard container, with a sampling frequency of 100 (450 data/card) and 17 minutes (2766 data/ibutton) respectively. The transport lasted 22.2 days for transoceanic shipping from Montevideo to Algeciras (Spain) plus 9.5 days in Spain to Cartagena, including waiting times for inspections in port. It can be noted that in all locations (39 TurboTag) the registered temperatures were on average 2.66ºC above the set point. The minimum average temperature was 5.41ºC, corresponded to the sensor located at the evaporator outlet, while the maximum temperature was registered at the evaporator inlet (10.53ºC). The average standard deviation (SD) of the sensors along the time of transoceanic transport was ?.0.171ºC, while the average spatial SD almost quadrupling this value (?.0.667ºC). The SD increased a 51.98% and a 43.93% respectively during the short distance transport. Data analysis shows spatial (phase space) and temporal sequencing diagrams and reveals a significant heterogeneity of temperature at different locations in the container, which highlights the ineffectiveness of a temperature control system based on a single sensor, as is usually done.
CIGR Section VII International Technical Symposium on Innovating the Food Value Chain . Postharvest Technology and Agri-Food Processing
Stellenbosch, South Africa
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PostHarvest Africa'12

Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: LPF-TAGRALIA: Técnicas Avanzadas en Agroalimentación