2. Methods
2.1. Manufacture of food waste mixture (FWM)
Fresh food waste (79% moisture) collected from several
oriental restaurants in Seoul, Korea was used in this experiment.
The food waste was composed primarily of cooked
rice, meat and vegetables. For pre-treatment, the food
waste was ground and screened for foreign material
removal with a screening grinder (Deplus Engineering Inc.,
Korea). Food waste (225 kg lots) was mixed 112.5 kg of
bakery by-product, 87.5 kg of barley bran, 50 kg of wheat
bran and 25 kg of broiler poultry litter which had been
deep-stack processed as described in Kwak and Park
(2003). The ratio of the ingredients was 16.1:34.8:26.8:
15.2:7.1 on a DM basis. An aerobic microbial culture was
added at the level of 0.3% on a DM basis to hydrolyze
starch to simple carbohydrates in the FWM. The aerobic
microbial culture developed by Sakai and Kubota (1989)
was composed primarily of Bacillus spp. Bakery by-product,
barley bran and wheat bran were used as sources of
energy and as water absorbents and broiler poultry litter as
source of readily available N and minerals for fermentative
microbes. Bakery by-product was a dried mixture of various
bakery and bread by-products. The chemical composition
of the final mixture was as follows: DM 53.9%, crude
protein 16.1%, neutral detergent fiber 26.5%, and acid
detergent fiber 13.7%.