| Poultry processing offal, blood and dissolved air floatation (DAF) sludge, and poultry carcasses on farms represent a major by-product and waste problem for the poultry industry. In this study, laboratory and field experiments were conducted to demonstrate the feasibility of using direct chemical acidification and lactic acid fermentation to stabilize/preserve these materials for subsequent treatment and recycling into poultry feeds. Direct acidification involved addition of acid(s) to ground offal, blood-offal mixture, and carcasses, while fermentation involved a supplementation with a carbohydrate substrate. Tested variables were acid type and concentration, carbohydrate type and concentration, incubation temperature and time, poultry waste type, commercial lactic acid silage culture supplementation, and pre-acidified fermentation. Chemical and microbiological changes in samples were monitored during storage. Among the acids, 2% (w/w) of 90% formic acid was most economical and effective. Fermentation with indigenous lactic acid bacteria and 15% (w/w) brewers solubles as supplementory substrate proved, however, to be the most economically and technically feasible method for stabilizing poultry offal, DAF sludge-offal mixture, and poultry carcasses during storage for 60 days. Lactic fermentation retained nutrients (crude protein and fat) and eliminated bacterial pathogens (Salmonella spp. and Campylobacter jejuni). Incubation temperatures between 30... |
