3.2. Survival of the “Big Six” non-O157 STECs and O157:H7 in
strawberry puree under HPP
Table 1 shows the survival of the “Big Six” non-O157 STECs and
E. coli O157:H7 in FSP treated at different pressure (150e450 MPa)
and time (5, 15, and 30 min) combinations. The CFUs on SMAC
plates after 37 C, 24 h and 48 h incubation showed no significant
difference in survival counts (i.e. P > 0.05, ANOVA). The TSA results
with “Big Six” (37 C and 24 h) indicated the difference between
TSA and SMAC was about 1.0e1.5 log CFU/g at pressure 250 MPa
and approached to below detection level at 450 MPa. TSA always
had the higher counts than SMAC, e.g. 6.0 vs. 4.5 log CFU/g,
respectively, at 250 MPa and 5 min treatment. If we assume TSA
plate counts were all STECs, the HPP impact may be
underestimated.