 Virus-Serum-Toxin Act 1913 (21 USC 151-158) This law was enacted largely because of public concern over the importation of contaminated veterinary vaccines from Europe and in reaction to complaints about worthless and contaminated hog cholera products being sold throughout the country.The new law required the USDA to ensure that veterinary biologics (vaccines, bacterins, antiserums and similar products) sold in interstate commerce are pure, safe, potent, and efficacious.In 1985, the Virus-Serum-Toxin Act was amended to include biologics sold intrastate.