The quantification levels of thermally inactivated HAV in shellfish samples with or without pretreatment with PMA–0.5% Triton are shown in Table 6. When shellfish concentrates were used undiluted, less than 0.5 log reduction was observed after PMA–0.5% Triton pretreatment indicating low performance of the pretreatment. Therefore, in order to assess the effect of the matrix, shellfish concentrates were ten-fold diluted and further inoculated with thermally inactivated HAV at concentrations of ca. 6 × 104, 6 × 103 and 6 × 102 TCID50. No detection of thermally inactivated HAV by the PMA–0.5% Triton pretreatment was observed at the lowest inoculum (i.e. 6 × 102 TCID50) whereas at higher levels, reductions of 1.10 to 1.95 logs were recorded (Table 6).