3. Results
3.1. Efficacy of pretreatment combining viability dyes and surfactants for the selective detection of infectious HAV in lettuce wash water
As a first step in exploring the potential of viability dyes to be applied in the fresh-cut industry, aliquots of thermally inactivated HAV suspensions (containing ca. 6 × 104 TCID50) were added in lettuce wash water and treated with 20 μM EMA or 50 μM PMA. Results showed that both viability dyes, PMA and EMA, reduced the signal of inactivated HAV by 3.17 and 2.17 logs, respectively (Table 2). When surfactants, i.e. Triton and Span 20, were combined with viability dyes (Table 3) only the combination of PMA and 0.5% Triton eliminated the signal of thermally inactivated HAV by more than 3.4 logs. The use of Span 20 rendered similar or even worse results than the use of the viability dyes alone.