Risk analysis in the manufacture of veterinary biologicals.

"Primum non nocere' must be the first quality of veterinary immunological medicinal products. Throughout the manufacturing process, stage by stage, various ingredients and/or operations could be responsible for safety problems observed when the product is administered. During the preliminary stages, various ingredients--e.g. master seed strains (virus, bacteria or parasite), cell substrates (cell-lines or primary cells) and substances of animal origin--could be contaminated by extraneous agents. These represent the most important risks. During the process--i.e. preliminary stages, microorganism growth, downstream processing (harvest, purification, concentration, inactivation, etc.), formulation, filling, freeze-drying and finally packaging--environmental conditions (working areas, equipment, etc.) might also be defective and responsible for product contamination. The author examines all aspects of risks and their assessments through consideration of "good manufacturing practice' based on quality assurance and quality control systems.