Clostridial toxins are amongst the most toxic substances known to science (Middlebrook, 1995). In the United States and other countries, human exposure to Clostridium botulinum toxins usually occurs through food poisoning, wound botulism and colonizing infections in neonates. Recent events have heightened concern about the possibility of botulinum toxins being used in a bioterrorist attack. In order to be prepared for a biological attack as well as the usual human exposures, numerous therapeutic products have been or currently are undergoing development to treat or prevent botulism, including the use of human or equine derived antibodies for post-exposure prophylaxis of botulinum toxin exposure (Gelzleichter et al, 1999; Hibbs et al, 1996; Metzger and Lewis, 1979 and Keller and Stiehm, 2000).