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Effect of alginate coatings with cinnamon bark oil and soybean oil on quality and microbiological safety of cantaloupe

Zhang, Yue, Ma, Qiumin, Critzer, Faith, Davidson, P. Michael, Zhong, Qixin
International journal of food microbiology 2015 v.215 pp. 25-30
Escherichia coli O157, Listeria monocytogenes, Salmonella enterica, bark, cantaloupes, cinnamon, coatings, color, detection limit, firmness, microbiological quality, molds (fungi), pathogens, sodium alginate, soybean oil, total soluble solids, weight loss, yeasts
The quality and microbiological safety of cantaloupes can potentially be improved using antimicrobial coatings that are able to maintain effectiveness throughout storage. The objective of this work was to study the effect of coating mixtures containing sodium alginate and cinnamon bark oil (CBO) on the quality of cantaloupes and the survival of inoculated bacterial pathogens and naturally occurring yeasts and molds during ambient storage at 21°C. Cantaloupes were dipped in mixtures containing 1% sodium alginate with or without 2% CBO and 0 or 0.5% soybean oil (SBO). Weight loss and total soluble solids content of the flesh were not significantly different among coating treatments. However, changes in color and firmness of cantaloupes were delayed to different extents after coating, most significantly for the CBO+SBO treatment. Cocktails of Salmonella enterica, Escherichia coli O157:H7, or Listeria monocytogenes inoculated on cantaloupes were reduced to the detection limit (1.3logCFU/cm2) and completely inhibited during the 15-day storage by the CBO+SBO treatment, while L. monocytogenes and S. enterica reached populations of 2.9logCFU/cm2 and 2.4logCFU/cm2, respectively, on cantaloupes coated with CBO alone. Antimicrobial coatings, especially with SBO, also reduced yeast and mold counts on cantaloupes by 2.6logCFU/cm2. SBO improved the retention of CBO during storage suggesting it is related to the enhancement of quality and microbiological safety. Findings demonstrated the potential of the antimicrobial coating system studied to improve microbiological safety and quality of cantaloupes.