Effect of Thermal Treatment on the Disinfection of Infectious Waste by Fry-Drying Method Using Vegetable Oil

Ramer P. Bautista, Jovita L. Movillon, Susana M. Mercado, Rex B. Demafelis, Moises A. Dorado, Manolito E. Bambase, Jr., Jewel A. Capunitan
Vol 18 No 2 (2015), pp.




Healthcare waste must be managed properly due to the hazards they impose on public health and the environment. In this study, an alternative method of treating infectious waste via thermal treatment using coconut oil was investigated in a laboratory-scale setup. The effects of oil temperature (121°C, 145°C and 170°C) and treatment time (10, 20 and 30 minutes) on bacterial growth and properties of simulated infectious wastes contaminated with Bacillus subtilis were determined. No bacterial growth was observed in the samples even at the seventh day after treatment using 145oC (20- and 30-minute treatment time) and 170°C (all treatment time). However, growth on enriched media occurred for the samples treated at 170°C, indicating possible spore germination. The treatment at 145°C and 30 minutes was effective in treating contaminated syringes and cloths. The contaminated meat samples underwent thermal degradation and had a maximum weight reduction of 74.1%, which was mainly due to moisture loss. The cloths, however, did not change in its appearance but syringes and other plastics melted and deformed. Thus, the thermal treatment was found to be a good disinfection method, causing severe damage to cells. The treated infectious waste materials can be disposed in landfills without potential recurrence of bacterial growth.


Keywords: Bacillus subtitles, Infectious waste, thermal treatment, coconut oil

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