Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/10/2012
Publication Date: N/A
Technical Abstract: Cantaloupe melon has been associated with outbreaks of foodborne illness linked with consumption of fresh-cut cantaloupes contaminated with Salmonella and E. coli 0157:H7 including the most recent outbreak of listeriosis suggesting the need to develop an effective antimicrobial wash treatment for the produce industry. The aim of this study was to investigate different combination of short chain organic acids generally regarded as safe (GRAS status) for inactivation of bacteria on cantaloupe fresh-cut pieces. Also, the impact of the treatments on the overall acceptability of fresh-cut cantaloupes was investigated. Whole cantaloupes purchased from a wholesale distribution center were held at 19 deg C for 24 hours and then inoculated with E. coli O157:H7 (8.35 log CFU/ml) suspension for 10 min. Melons were allowed to dry for 3 hours in a biosafety cabinet after which they were sanitized with water, 200 ppm chlorine and 2.5% hydrogen peroxide solution for 3 min. Fresh-cut pieces (~ 3 cm) cubes prepared from treated melons were dipped in 2% sodium lactate (NaL), nisin (12 micro-g/ml), EDTA (20 mM), sorbic acid (SA, 0.03%), and a combination of nisin+EDTA, NaL+nisin, SA+nisin and NaL+nisin+EDTA+SA for 30 seconds. Prepared fresh-cut cantaloupe pieces were monitored for microbial growth, appearance and overall acceptability during storage at 5 deg C, 10 deg C for 15 days and 20 degC for 48 h. Chlorine and H2O2 treatments reduced the E. coli populations on cantaloupe surfaces to 3.8 log CFU/cm2 and 3.4 log CFU/cm2, respectively. Aerobic bacteria and E. coli populations transferred to fresh-cut pieces after fresh-cut preparation averaged 2.5 log CFU/g and 1.6 log CFU/g, respectively. Washing fresh-cut cantaloupe pieces in NaL solution for 30 seconds reduced the bacterial populations by 0.5 log and enhanced the appearance and overall acceptability. Nisin and EDTA did not reduce microbial populations nor enhanced the appearance and overall acceptability the fresh-cut cantaloupes. However, a combination of NaL+nisin+EDTA+SA, nisin+EDTA, NaL+nisin and SA+nisin reduced microbial populations significantly (p<0.05). However, the overall acceptability score for these fresh-cut cantaloupe melons were 7 compared to 9 by NaL treatment alone. The result of this study indicates that treatments of fresh-cut cantaloupes with sodium lactate and storage of treated fresh-cut pieces at 5 deg C will improve the microbial safety and overall acceptability of the fresh-cut pieces.