This report examines the impact of process regulations mandated under the Pathogen Reduction/Hazard Analysis and Critical Control Point (PR/HACCP) rule by the Food Safety and Inspection Service of USDA on food safety process control. The current level of food safety found in U.S. meat and poultry food products is a result of process and performance regulations and management-determined actions brought about by market incentives. Processing regulations include sanitation and other tasks related to food safety; management-determined actions include capital investment and other actions independent of process regulations, but possibly driven by performance standards. Performance standards—regulations that allow manufacturers to reach an acceptable level of food safety in any manner they see fit—are not a subject of this report. This study used the share of samples testing positive for Salmonella spp. as a measure of food safety process control in meat and poultry processing plants and found empirically that management-determined actions account for about two-thirds of the reduction in samples testing positive for Salmonella spp., while process regulations account for about a third of the reduction. The importance of process regulation varies, but accounts for 50 percent or more of process control in about a quarter of plants, and in some plants accounts for the entire process control system.