Preservation of hatchery waste by lactic acid fermentation. 1. Laboratory scale fermentation

Department of Poultry Science, Pennsylvania State University, University Park 16802-3501, USA.

In Experiment 1, two types of hatchery wastes, including cockerel chicks (CC), and shell waste (SW) blended with CC (60:40 CC:SW), were ground and mixed with a by-product carbohydrate (5, 10, and 15% wt/wt) with or without a bacterial culture and fermented for a period of 21 d. Cockerel chicks fermented with 15% carbohydrate and the culture had a pleasant smell and little H2S production. Elevated H2S concentrations were recorded for CC:SW samples at all carbohydrate levels when the culture was not added. No NH3 was detected from any treatments during fermentation. The addition of culture to the CC and CC:SW by-products resulted in pH values lower (P < 0.05) than those without culture on Day 21, and the 15% carbohydrate treatment significantly reduced pH beyond the 5% carbohydrate. Final proximate composition of CC and CC:SW samples with culture were not significantly different from those without culture added. In Experiment 2, carbohydrate was added at 10.0, 13.3, 16.7, and 20.0% wt/wt to CC and CC:SW in the presence of the bacterial culture. Shell waste alone was fermented with 15, 20, and 25% carbohydrate and the culture. Moisture level in this experiment was adjusted to approximately 70% for all treatments. The lowest pH for the CC and CC:SW treatments was observed at the 16.7% carbohydrate level. Shell waste pH was better maintained at the 20 and 25% carbohydrate levels. After fermentation for 21 d CC, CC:SW and SW treatments from Experiments 1 and 2 contained negligible Escherichia coli, and no Salmonella were detected.