Feeding table scraps or swill to hogs has been blamed for the outbreak of foot-and-mouth disease in Europe, according to a Fox news report.

Although feeding scraps has long been recognized as a large disease risk, it is still legal in 33 states and Puerto Rico. About 2,700 farmers are licensed under U.S. law to feed discarded food to hogs. Federal rules require the swill to be cooked for 30 minutes to kill any pathogens.

USDA requires swill-feeding producers to be inspected at least quarterly, but some states require inspections more regularly. USDA also advised states to contact every swill-feeding producer within a month to ensure they are following the cooking and record-keeping rules.

Britain and Ireland are outlawing swill feeding as a result of the FMD outbreak, and the European Union is being pressed by several countries to impose an EU-wide ban.