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Postharvest Quality and Safety in Fresh-cut Vegetables and Fruits

Investigators
Joens, Lynn
Institutions
University of Arizona
Start date
2007
End date
2011
Objective
Evaluate and control unintentional and intentional microbial contamination of intact and fresh-cut produce. Fresh cut produce including spinach, lettuce, coleslaw, mixed greens/prepared salads, baby carrots, tomatoes, watermelon, cantaloupe, honeydew, pineapple, and combination fruit cups will be bought from the supermarket and tested for the presence of Salmonella and Campylobacter jejuni.
More information
Non-Technical Summary: Ready-to-eat products that require little to no preparation have undergone rapid growth in the food industry in recent years. Our objective is to determine the prevalence of Salmonella spp. and C. jejuni on fresh cut produce.

Approach: Fresh cut samples will be bought from randomized supermarkets and tested for C. jejuni and Salmonella. A minimum of six suppliers, if possible, will be tested as consolidation of many local and regional players with large firms have occurred. For C. jejuni, twenty-five grams of each fresh cut sample will be added to 100 ml of Bolton broth, macerated using a stomacher (Seward, London, U.K.) at 230 RPM for 45 seconds, and the resulting macerate separated into two portions. One portion will be serially diluted and plated onto CEFEX plates, then incubated in a 37 degrees C, 5% CO2 incubator for 2-5 days. The second portion will be incubated in a 37 degrees C, 5% CO2 incubator for enrichment for 24 hours, then serially 10-fold diluted and plated onto Abeyta-Hunt agar plates and incubated in a 37 degrees C, 5% CO2 incubator for 2-5 days. Beginning with day 2, each plate will be examined for colonies typical of C. jejuni. PCR and hippurate testing will be conducted to confirm the presence of C. jejuni. For Salmonella spp., twenty-five grams of each fresh cut sample will be added to 100 ml of Tetrathionate broth, macerated using a stomacher (Seward, London, U.K.) at 230 RPM for 45 seconds, and the resulting macerate separated into two portions. One portion will be serially diluted and plated onto XLD plates, then incubated in a 37 degrees C incubator for 24-48 hours. The second portion will be incubated in a 37 degrees C incubator for enrichment for 24 hours, then serially 10-fold diluted and plated onto XLD agar plates and incubated in a 37 degrees C incubator for 24-48 hours. Each plate will be examined for colonies typical of Salmonella and PCR and slide agglutination assays will be conducted to confirm the presence of Salmonella. Salmonella isolates will be sent to APHIS-USDA, Ames, IA for serotyping.

Funding Source
Nat'l. Inst. of Food and Agriculture
Project source
View this project
Project number
ARZT-137031-R-02-136
Accession number
210577
Categories
Bacterial Pathogens
Campylobacter
Salmonella
Commodities
Produce