Federal Swine Health Protection Act & Iowa Administrative Code Feeding Garbage to Animals
The Swine Health Protection Act identifies garbage as one of the primary sources for transmission in infectious or communicable diseases of swine, such as foot-and-mouth disease, African swine fever, hog cholera and swine vesicular diseases.
National Requirement for Garbage Preparation
Under the United States Code, garbage may be fed to swine only if treated properly to kill disease at a facility holding a valid permit or license to treat garbage. Garbage shall be heated to boiling (at least 212° Fahrenheit) for 30 minutes.
Iowa Code for Feeding Garbage to Swine
Even if heat treated to United States Code requirements, feeding garbage to swine in Iowa is illegal. The Iowa Administrative Code prohibits issuing a license to permit processing of any garbage for swine; therefore the Iowa Department of Natural Resources does not have any licensed garbage feeders.
At the national and Iowa level, individuals who feed their own swine garbage from their households are exempt from this rule.
The above 2010 map shows states that permit and prohibit garbage feeding to swine. Source