Abstract
Disinfectants for veterinary and livestock use, plus skin antiseptics, are critical elements for the control of
infectious agents, including zoonotic and antimicrobial-resistant micro-organisms, in managed animal
species. Such agents impact animal welfare, economic performance and human health. Testing of
disinfectants is needed for safety, efficacy and quality control. The present review examines the principal
types of test (carrier, suspension, surface and field) that have been developed or attempted, plus the
features inherent in the respective tests, particularly with respect to variability. Elements of testing that
have to be controlled, or which can be manipulated, are discussed in the context of real-world scenarios and
anticipated applications. Current national and international testing regimes are considered, with an
emphasis on the UK, continental Europe and North America, and with further detail provided in the
Supporting Material. Challenges to disinfectant efficacy include: the nature of the biological targets (bacteria,
fungi, yeasts, spores, viruses and prions), the need for economical and safe working concentrations, the
physical and chemical nature of contaminated surfaces, constraints on contact times and temperatures, the
presence of organic soil and other barrier or neutralising substances (including biofilms), and thoroughness
of pre-cleaning and disinfectant application. The principal challenges with veterinary disinfectant testing are
the control of test variability and relating test results to likely performance in variable field conditions.
Despite some ambitions to develop standardised field tests for disinfectants, aside from skin antiseptic trials
the myriad problems such tests pose with respect to cost, reproducibility and generalisability remain
intractable.