This is from the Federal Best Practices Document:
http://www.bifsco.org/CMDocs/BIFSCO/Best Practices/BestPracslaught Sept 09.pdf
Pre-evisceration carcass wash:
Carcasses should be subjected to a water rinse and/or antimicrobial treatment shortly after hide removal.
Carcass Wash
The carcass washing procedure is designed to remove incidental contamination (blood specs, bone dust, hair, etc.). Carcass washing is designed to impact carcass quality and to prepare the carcass for chilling. The washing should proceed from the top of the carcass in a downward direction to prevent recontaminating an area. Washing should be completed before shrouding, if applicable. :
If using a wash cabinet, the carcass wash should address the spray patterns, the pressure of the water, the volume of water applied, and the time the carcass is in the cabinet. The pressure should not be high enough to drive the contamination into the fat and carcass tissue. Also, the drains must be working properly to prevent backup that could create additional contamination as the carcass passes through the wash cabinet.
The cabinets must have a preventive maintenance schedule to ensure that the equipment is functioning as designed, including nozzles, filters, etc. The parameters of the equipment should be documented to demonstrate that it is efficient.
If the carcass wash is conducted by hand with a hose, then the lift must be sufficient to reach the top of the carcass and the wash should be sufficient to clean the carcass.
Carcass wash areas, hoses and equipment should be mainand sanitary condition.