Evaluation of Steady-State Gaseous Chlorine Dioxide Treatment for the Inactivation of Tulane virus on Berry Fruits

The effectiveness of steady-state levels of gaseous chlorine dioxide (ClO 2 ) against Tulane virus (TV), a human norovirus surrogate, on berries was determined. The generated ClO 2 was maintained at 1 mg/L inside a 269 L glove box to treat two 50 g batches of blueberries, raspberries, and blackberries, and two 100 g batches of strawberries that were immersion coated with TV. The standardized/normalized treatment concentrations of ClO 2 ranging from 0.63 to 4.40 ppm-h/g berry were evaluated. When compared to untreated TV contaminated berries, log reductions of TV were in excess of 2.9 log PFU/g for all berry types and conditions tested, indicating that ClO 2 was highly effective. In general, the efficacy of all ClO 2 treatments on log reductions of TV on all berries was not significantly different ( p < 0.05). The average log reduction with strawberries, raspberries, blueberries, and blackberries, treated with the lowest ClO 2 concentration, 0.63 ppm-h/g, were 2.98, 3.40, 3.82, and 4.17 log PFU/g, respectively. Overall results suggest that constant levels of ClO 2 could be quite effective against foodborne viruses.