Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/21/2016
Publication Date: 6/28/2016
Citation: Ukuku, D.O., Mukhopadhyay, S., Geveke, D.J., Olanya, O.M., Niemira, B.A. 2016. Minimal thermal treatments for reducing bacterial population on cantaloupe rind surfaces and transfer to fresh-cut pieces. Journal of Food Protection. doi: 10.4315/0362-028X.JFP-16-046.
Interpretive Summary: Foodborne illness associated with consumption of fresh-cut fruits contaminated with bacteria continues to be a problem for the produce industries and consumers alike. The need for minimal processing treatment that can reduce transfer of bacteria from cantaloupe rind to the flesh during fresh-cut preparation is needed. Cantaloupes contaminated with Salmonella, E. coli O157:H7 and L. monocytogenes populations were washed and or treated with water or 3% hydrogen peroxide heated to 80 degrees C before fresh-cut pieces were prepared. No bacterium was recovered in all fresh-cut pieces prepared from heated (80 degrees C) water and 3% hydrogen peroxide treated even after enrichment procedures. Recovery of transferred pathogens including injured bacteria occurred at day 6 and 3 of storage at 5 degrees C and 10 degrees C, respectively. The results of this study indicate minimal thermal treatments of water and 3% hydrogen peroxide are an excellent sanitizer for inactivating bacteria on melon rind surfaces before fresh-cut preparation.
Technical Abstract: Cantaloupe melon has been associated with outbreaks of foodborne illness due to consumption of contaminated fresh-cut pieces. Surface structure and biochemical characteristics of bacteria play a major role on how and where bacteria may attach and also complicates decontamination treatments. 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 degrees C for 7 days before washing and minimal thermal treatment using 3% hydrogen peroxide (H2O2) and water H2O. Strength of pathogen attachment (SR-Values) and efficacy of H2O and 3% H2O2 including thermal treated H2O2 and H2O to detach and kill bacteria as well as reduce transfer to fresh-cut pieces was investigated. 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 degrees C and day 3 at 10 degrees C. The results of this study suggest that minimal thermal H2O and 3% H2O2 treatment at 80 degrees C of cantaloupes surfaces designated for fresh-cut preparation will enhance the microbial safety of fresh-cut pieces.