Pseudorabies, a herpes virus outbreak fatal to livestock and baby pigs has spread to at least 23 hog farms in Southern California, authorities reported. Meat from an infected pig is safe to eat, the state Department of Food and Agriculture said. Although adult swine can spread the virus to other mammals, including cattle, sheep and pets, the disease has not spread to humans. Once an adult hog is infected, it does not necessarily die, but does remain infected for life. The state warned 20 farmers who bought pigs from three farms, two near Corona and one in Ontario, that the swine may be infected. Many have chosen to destroy their herds. The department has quarantined the three farms to try to prevent the disease from spreading.