Scale-up study on the supercritical carbon dioxide sterilisation of oil palm fresh fruit bunch

Abstract

Existing steam sterilisation method of oil palm fresh fruit bunch (OP-FFB) requires huge quantities of water and about 30%-60% of the water results in palm oil mill effluent (POME). In order to circumvent the perennial POME generation problem, it requires a waterless sterilisation system of OP-FFB. The present study was conducted to determine the sterilisation efficiency of OP-FFB using a pilot scale supercritical carbon dioxide (SC-CO2) technology. The sterilisation efficiency was evaluated based on the inactivation of Bacillus spp. and Aspergillus spp. in OP-FFB with varying SC-CO2 pressure (10-30 MPa), temperature (40°C-80°C) and treatment time (15-90 min). Complete inactivation of the microorganisms in OP-FFB was obtained after 45-90 min at treatment range of 10-30 MPa and 40°C-80°C. The findings of the present study reveal that the SC-CO2 sterilisation is a conceivable technology to be used in OP-FFB sterilisation, replacing the current water steam sterilisation technology.