Mesophilic composting of food waste and bacterial pathogen reduction

The objective of this study was to evaluate the indicator efficiency of food waste composting using a small-scale solid waste composting system to reduce indicator bacteria concentrations. A raw compost material consisting of 1/3 volume of apple residue, 1/3 volume of material composted, 0.5/3 volume of poplar leaves, 0.25/3 volume of grass and 0.25/3 volume of rumen ingredients. The material have a 20:1 C/N, 75% water content and organic substances in 65% ratio as well as pH 6.98 as a initial pH. After 290 hours composting period, the material composted has 12:1 C/N, 70% humidity, 60% organic substances and 9.50 of pH. At the beginning of the composting process. overnight broth cultures 11 log CFU /mL of Escherichia coli, Proteus spp. and Klebsiella spp. were inoculated to the composting mixture, giving a final concentrations as 7,77 log CFU/g, 8,47 log CFU/g and 8,77 log CFU/g respectively. Indicator organisms have not been detected after 8(th) day, which shows that the material composted has no infection risk.