Attachment of Salmonella on cantaloupe and effect of electron beam irradiation on quality and safety of sliced cantaloupe

Increase in consumption of fresh produce over the past decade has resulted in a rise in incidents of foodborne outbreaks due to pathogens. Chemical sanitizers have been extensively used in the industry for decontamination of fresh produce. However, they are ineffective in certain commodities and under certain processing conditions, necessitating the evaluation of alternative technologies. Electron beam irradiated sliced cantaloupe were tested for 21 days of storage for total aerobic bacterial counts, texture, color and sensory parameters as a function of irradiation doses 0, 0.7 and 1.4 kGy and the wash treatments, water and 200 mg/L chlorine applied to the melons before cutting. Melons washed only with water prior to cutting had total aerobic bacterial counts of 4.0, 2.0 and 0.8 log cfu/g on day 0 at irradiation doses of 0, 0.7 and 1.4 kGy respectively. On day 0, melons washed with chlorine prior to cutting had total aerobic bacterial counts of 2.7, and 0.7 log cfu/g at irradiation doses of 0 and 0.7 kGy and below detection limit at 1.4 kGy. Texture measured as compression force was lower only for cantaloupe irradiated at 1.4 kGy. Irradiation did not affect objective color and descriptive attribute flavor and texture sensory attributes of cantaloupe. Irradiation reduced Salmonella Poona by 1.1 log cfu/g at 0.7 kGy and 3.6 log cfu/g at 1.5 kGy. The D-value of S. Poona on irradiated sliced cantaloupe was found to be 0.211 kGy. Among the spoilage organisms, lactic acid bacteria and mold were reduced effectively by irradiation but there was no significant effect on reduction of yeasts. Our results show that electron beam irradiation in combination with chemical sanitizers is effective in decontamination of fresh-cut produce. Electron microscopy images provided valuable information on attachment sites of S. Poona on cantaloupe rind. The ineffectiveness of chemical sanitizers due to possible inaccessibility to pathogens in these attachment sites provides the basis for application of irradiation in decontamination of fresh produce.