Botulinum neurotoxin (BoNT) is produced by the anaerobic bacterium Clostridium botulinum during its vegetative growth. C. botulinum strains are commonly found in the environment, animals and in food raw materials. The bacterium forms dormant endospores, which do not produce toxins. However, the spores are highly resistant to environmental stress and thus maintain the toxic potential in environmental and agricultural systems and the food chains that occasionally provide conditions favourable for spore germination and outgrowth into a toxic culture. Besides causing botulism to man and animals, BoNTs are widely exploited by medical industries in treatment of spastic diseases. Thoroughly validated, sensitive and specific assays for neurotoxin detection are thus needed not only for laboratory diagnostics of botulism outbreaks but also for potency testing of the pharmaceutical neurotoxin products.