Aichi virus inactivation by heat in 2‐ml glass vials

Abstract

Aichi virus (AiV) that results in gastroenteritis worldwide, is spread through contaminated shellfish and water. The resistance/tolerance of AiV to common inactivation processes along with the absence of commercially available vaccines makes it necessary to study its thermal inactivation kinetics. This research evaluated the heat inactivation of AiV in cell-culture media using 2-ml sterile glass vials by the linear and Weibull models. Heat treatments of AiV titers of 7 log plaque forming units (PFU)/ml were conducted thrice in a water-bath at 50, 54, and 58 • C for up to 90 min. Plaque assays for each dilution in duplicate were used to determine infectious virus titers. Linear model D-values for AiV at 50 ± 1 • C (± = standard error) (come-up time = 68 s), 54 ± 0.7 • C (130 s), and 58 ± 0.6 • C (251 s) were 43.3 ± 4.23 (R 2 = 0.40, RMSE = 0.56), 5.69 ± 0.28 (R 2 = 0.80, RMSE = 0.43), and 1.20 ± 0.63 min (R 2 = 0.69, RMSE = 0.39), respectively, and the linear model z-value was 5.14 ± 0.39 • C (R 2 = 0.99, RMSE = 0.08). For the same temperatures, the Weibull model t d = 1 values were 20.98 ± 8.8 (R 2 = 0.62, RMSE = 0.46, α (scale parameter) = 2.30, β (shape parameter) = 0.38), 3.84 ± 0.69 (R 2 = 0.85, RMSE = 0.38, α = 1.08, β = 0.66), and 0.87 ± 0.10 min (R 2 = 0.80, RMSE = 0.32, α = 0.22, β = 0.61), respectively and the z-value (using T d = 1 ) was 5.79 ± 0.22 • C (R 2 = 1.0, RMSE = 0.03). A better fit was obtained with the Weibull model for log reductions versus time with higher R 2 and lower RMSE values. Application of AiV inactivation parameters can help reduce the risk of AiV outbreaks.

Inactivation of Tulane virus and feline calicivirus by aqueous ozone

“…In order to determine inactivation parameters, models such as the linear regression model provide standards to estimate D ‐values, that is, time (min) required to cause 1 log PFU/mL reduction of infectious viruses that can predict the treatment conditions (time) required for higher log reductions (Ailavadi et al., 2021; Bozkurt et al., 2013). The calculated D ‐values for FCV‐F9 with D = 0.82 ± 0.01 min and TV of D = 0.96 ± 0.08 min with ~1 ppm ozone treatment within clear sterile water samples (Table 4) demonstrated that the linear D ‐values were close for FCV‐F9 and TV inactivation at RT.…”

“…This linear line equation has a "slope of −1/D, where the number of viral survivors in PFU/mL after an exposure time t (min) is described as N(t) that has an initial viral population of N 0 " (Bozkurt et al, 2013;Patwardhan et al, 2020;Ailavadi et al, 2019Ailavadi et al, , 2021. The D (min)-value is then derived from this equation as the time of treatment that is needed to reduce the initial target viral population by 10-fold (Ailavadi et al, 2021).…”