Fig 1.
Die-off and attachment of E. coli on watermelon surfaces.
Average E.coli count on the watermelon surfaces and FSMA- PSR predicted count on produce surfaces based on the die-off rate of 0.5 log CFU/day, up to 120 h (Day 6). The population of loosely attached and strongly attached cells is also shown for up to 120 h. SR Value (Attachment Strength) = Strongly Attached Cells/ Total Cells (strongly attached+ loosely attached). Data are shown as mean values ± standard deviation.
Fig 2.
Scanning electron micrographs of E. coli inoculated watermelons surfaces.
SEM images (SEI 10 KV, 5,000x & 10,000x) of watermelon surfaces after inoculating with E. coli and leaving them in an agriculture field for 0 h (A), 24 h (B), 48 h (C), 72 h (D), 96 h (E) and 120 h (F).
Fig 3.
Efficacy of chlorine (150 ppm for 3 min) on E. coli inoculated watermelon surfaces.
30 min: Inoculated 30 min prior to the treatment; 120 h: Inoculated 120 h prior to the treatment. The bar diagrams with different lowercase letters on the top are significantly different (P < 0.05) from each other. The detection limit of the test was 0.28 log CFU/cm2.
Table 1.
Weather conditions during the study period.