Clarification and Decontamination of Poultry Chiller Water for Recycling

Abstract

The chilling operation in poultry processing involves dipping birds in slush ice for rapid removal of body heat. The United States Department of Agriculture Food Safety and Inspection Service (USDA/FSIS) permits recycling of reconditioned chiller water to meet fresh water intake requirements, thereby reducing refrigeration, water use, and liquid waste effluent. Laboratory scale filtration experiments used four types of perlite filter aids applied as a precoat and as body feed (filter aid mixed with the water entering the filter). Results showed that rate of filtrate flow dropped rapidly regardless of type used. Rapid filtrate flow lasted only 20 min from the start of a cycle, suggesting that the frequent cycling and application of a fresh filter aid precoat with each cycle would use large quantities of filter aid. Mean filtration rate defined as the ratio of filtrate volume to length of filtration cycle at a cycle time of 20 min was 24.1 L/min (m2 filter area) when the finest filter aid was used. Use of this filter aid also resulted in filtrate clarity and total aerobic count reduction, which were consistently within the range specified under FSIS guidelines for recycling. Mean filtrate flow during a 20-min cycle was 39.8 L/min (m2 filter area) when a slightly coarser filter aid was used; filtrate clarification was adequate. However, total microbial reduction sometimes fell below 60%, suggesting possible use only when microbicides are added to the reconditioned water prior to recycling.