A battery-powered air sampler to monitor the evolution of ethylene during reefer container transport of fruit

Samenvatting

Over the last decade we have frequently encountered the question how the ethylene concentration evolves over time during reefer container transports of fruit. Unfortunately we were, till recently, not able to answer those questions. Ethylene is hard to measure, and hardly any data are (publicly) available on ethylene concentrations occurring during reefer transport. We failed to find a suitable device to monitor ethylene in reefer containers. Therefore we decided to develop our own air sampler. Since spring 2022 it has been deployed fulltime to collect air samples during reefer container transports of perishables. The battery-powered programmable device contains 24 air sample bags of 0.5-L, which are filled sequentially at a flexibly programmable sample interval. After completion of a shipment the device is taken to the lab, where the gas content of the air samples is analysed with a gas chromatograph tuned to measure ethylene. Over the course of four consecutive commercial avocado shipments in reefer containers the air sampler operated flawlessly and proved fit for the purpose of monitoring the evolution of ethylene concentrations during commercial intercontinental reefer container transport of fruit. In the absence of good replicates it is not possible to draw conclusions from the collected data so far, but the data do yield some interesting indications, which might serve as good hypotheses for further research on ethylene in controlled atmosphere container transport of avocado. One of those interesting indications is the possible effect of delays between stuffing and the start of cooling on the accumulation of ethylene, and how that ethylene accumulation affects avocado quality at unstuffing.