Thermal Inactivation of Multiple Veterinary-Relevant Viruses: Effects of Environmental Conditions, Surface Type, and Organic Matrix

Heat is widely used to decontaminate livestock environments, yet performance varies with virus, surface, moisture, and organic load. We evaluated the effects of temperature (50, 60, 70 °C) and exposure time on the viability of 10 veterinary-relevant viruses (or surrogates) placed on four nonporous surfaces (plastic, rubber, aluminum, stainless steel) under dry or wet conditions, and in organic matrices (blood, wheat straw, complete feed). Infectivity was quantified by TCID₅₀ using independent duplicate experiments with duplicate titrations. Moist heat consistently outperformed dry heat: at 60-70 °C, all enveloped viruses, and most non-enveloped viruses were inactivated on surfaces within 5 min, while porcine parvovirus (PPV) remained the outlier, requiring ≥60 min. In contrast, dry heat allowed several viruses to persist for 24 h at 70 °C, underscoring that temperature alone is an unreliable predictor of rapid decontamination in the absence of humidity. Organic matrices modulated outcomes in a substrate- and virus-dependent manner, with some combinations accelerating inactivation and others prolonging survival to ≥180 min at ≥60 °C. These findings support matrix-aware, heat-assisted protocols for facilities and transport (e.g., 70 °C for ≥10 min under high humidity for most enveloped viruses), while recognizing exceptions such as PPV. The data provide actionable parameters to optimize thermo-assisted decontamination in veterinary systems.