Purpose: In this study, we evaluated the effect of minimal thermal treatment using 3% hydrogen peroxide (H2O2) and water H2O at 80°C to reduce microbial populations on cantaloupe rind surface and fresh-cut pieces.
Methods: Whole cantaloupes rind surfaces were inoculated with Salmonella, Escherichia coli O157:H7 and Listeria monocytogenes at 4.5, 5.1 and 3.6 log CFU/cm2, respectively and were stored at 5 and 22°C for 7 days before washing and minimal thermal treatment using 3% hydrogen peroxide (H2O2) and water H2O. All treatments were for 300 s and the rind surfaces were examined with scanning electron microscopy and bacterial inactivation on a range of agar media.
Results: Efficacy of washing treatment in reducing attached bacteria and minimizing transfer to fresh-cut pieces were investigated at day 0, 3 and 7 of storage. Initial attachment was highest for E. coli O157:H7 and lowest for L. monocytogenes, but Salmonella exhibited the strongest attachment at all days tested. Washing with 3% H2O2 alone led to significant (P<0.05) reduction of bacteria and caused some changes in bacterial cell morphology. Bacterial inactivation on cantaloupe rind appeared to be dependent on duration of contact time. No bacterial pathogen was determined in fresh-cut pieces prepared from minimally heated 3% H2O2 and H2O treatments including enriched fresh-cut samples. Microbial safety for all fresh-cut pieces from treated cantaloupes was established at day 6 of storage at 5°oC and day 3 at 10°C.
Significance: Minimal thermal H2O and 3% H2O2 treatment at 80°C of cantaloupes surfaces designated for fresh-cut preparation will enhance the microbial safety of fresh-cut pieces, and will drastically reduce the incidence of foodborne illness, and costly recalls of contaminated produce.