Almonds (Prunus dulcis) are among the most popular dried fruits all over the world for their high nutritional and health value.
The almond is a crop practiced in many countries of the world including temperate, sub-tropical, and tropical regions in which is considered an economically important commodity, grown for domestic consumption, trade, and it is extensively used in the food industry.
However different insects such as Ephestia kuehniella can infest it unshelled almonds during production, storage and other post-harvest processes, which causes quality, quantity, and monetary losses.
In order to disinfect almonds without using chemical methods a pilot plant was designed and built for the continuous treatment of unshelled almonds by using microwaves. The plant is equipped with a tubular treatment chamber with internal agitator in which disinfestation takes place in physical way by using five magnetrons of 1.5 kW of power each, operated by PLC. Functional tests were performed on the pilot plant using maximum electrical power (7.5 kW) in order to define and map the operating parameters: specific energy, residence time, mass flow rate and surface temperature, in a ranges of electric motor frequency 30-80 Hz.
In order to investigate mortality condition for Ephestia kuehniella in its different stages of life (eggs, 2 days old larvae and 21 days old larvae), an experimental test plan was carried out. Six trial tests were performed seven times for each condition and type of pest with electrical power of 7.5 kW. At the end of the tests, the specific energy to guarantee the total mortality of the three life stages of the insect was determined. Additional tests to decrease electrical power and increasing residence time with costant specific energy value confirmed the totally mortality condition for Ephestia kuehniella in the three stage life.