A comparison of the influence of different low-cost cooling technologies on tomato cooling time and temperature

Cooling of fruits and vegetables is very critical for postharvest shelf-life extension. The field heat removal should take place immediately after harvest. Different low-cost fruit and vegetables cooling technologies that were proven to be affordable by smallholder farmers are required to ensure better marketability for reasonably extended period in a supply chain. The aim of this study was to compare the effectiveness of different cooling methods in terms of cooling time requirement of the fresh tomato fruit. The cooling technologies used in this study include the low-cost evaporative cooling (EC), CoolBot-air conditioner (CBAC) and the combinations EC with CBAC which are known to be feasible technologies for low-income farmers in arid and semi-arid regions. Fresh tomato cooling experiment to remove field heat during summer was conducted for 72 h for each of the EC, CBAC and EC+CBAC storage systems. The results showed that 6, 12-18 and 24 h were required to reduce the temperature of tomatoes using CBAC, EC+CBAC and EC alone, respectively. The EC, CBAC and EC+CBAC reduced and maintained the micro-environment air temperature inside the coolers to 6, 8-13 and 19°C, respectively. The ambient temperature varied between 34 and 40°C. Hence, CBAC, EC+CBAC and EC can be from the best to the lowest choice by farmers, respectively, for cooling the fruit by reducing the field temperature after harvest.