Purpose: The purpose of this study was to determine if exposure to AITC vapor for different time and temperature combinations reduces Salmonella enterica serovar Michigan and Listeria monocytogenes on the surface of ‘Athena’ cantaloupe (Cucumis melo L).
Methods: Fifty µl of S. Michigan or L. monocytogenes was inoculated onto whole cantaloupes in 22mm diameter circles and allowed to dry for 90 min. (final inoculation was 6.35 or 6.30 log CFU/circle, respectively). Each cantaloupe was placed inside a 12l glass desiccator and exposed to AITC vapor or control (no treatment) at 25 or 35°C for 1 or 24h. Vapor was created by dispensing liquid (either 100 or 300µl) onto Whatman No. 1 filter paper and attaching it to the lid of the desiccator prior to sealing. Following treatment, the 22mm diameter sections were removed, homogenized and plated onto appropriate agar.
Results: Treatment of cantaloupe for 24h resulted in lower populations of pathogens than 1h (P < 0.05). However, there were no significant differences in pathogen recovery between vapor treatment volumes (100 or 300µl) after 24h at 35°C. The higher vapor concentration at 25°C for 24h caused the greatest reduction of S. Michigan (3.92 log CFU/10 g) and at 35°C for 24h against L. monocytogenes (3.86 log CFU/10 g). At 35°C the higher vapor concentration caused the greatest reduction of both pathogens after 1h (3.68 log CFU/10 g for S. Michigan and 1.75 log CFU/10 g for L. monocytogenes, respectively).
Significance: AITC vapor shows promise as a way to reduce pathogens on fresh cantaloupe.