Brick walled and box type evaporative cooling systems for vegetable storage

Simple evaporative coolers (EC) create cool and humid conditions to slow quality deterioration of fresh vegetables caused mainly by moisture loss. When used for tomato, chili, cabbage, Chinese kale, Chinese mustard and aromatic mustard they can reduce weight loss by 50-80% compared with storage under ordinary room conditions.

Two types of EC have been tested: The brick-walled EC is made of clay bricks designed to neatly fit the containers of produce to be placed inside. The structure is double-walled, and the 10-20 cm space between walls can be filled with sand as insulator and kept moist with water. A jute sack covering a wooden frame over the structure is kept moist with water.  The box EC is made of wooden slats and covered with a tight fitting jute sack kept moist with water.

• Use good quality, unblemished vegetables.
• Wash with clean water or 100-200 ppm chlorine-treated water (except cabbage, as washing could favor decay).
• Air-dry the produce and then place in the EC.
• Keep insulator (sand and jute sack) moist throughout the storage period.
• Periodically inspect produce and cull out decayed, yellowed or overripe produce.