title: Survival of Salmonella Newport on Whole and Fresh-Cut Cucumbers Treated with Lytic Bacteriophages.
abstract: Salmonella enterica associated with consumption of cucumbers ( Cucumis sativus ) has led to foodborne outbreaks in the United States. Whole and fresh-cut cucumbers are susceptible to S. enterica contamination during growing, harvesting, and postharvest handling. The application of lytic bacteriophages specific for S. enterica was evaluated to reduce Salmonella populations on cucumbers. Unwaxed cucumbers ('Lisboa' variety, or mini-cucumbers purchased at retail) were inoculated with Salmonella Newport (5 log CFU per cucumber) and were sprayed with 3.2 mL of phosphate-buffered saline (control) or 10 log PFU/ml of SalmoFresh, a Salmonella-specific bacteriophage preparation (phage), to deliver 4.76 × 107PFU/cm2. Cucumbers were stored at 10 or 22°C for 7 days. Inoculated mini-cucumbers were sliced with a sterile knife to investigate Salmonella transfer to mesocarp, and cut pieces were stored at 4°C for 2 days. Populations (log CFU per cucumber) of Salmonella Newport on phage-treated whole cucumbers were significantly (P < 0.05) smaller (2.44 ± 0.94) than on control-treated cucumbers (4.27 ± 0.37) on day 0. Populations on phage-treated cucumbers stored at 10°C were 1.72 ± 0.77 and 1.56 ± 0.46, which were significantly lower than those on control-treated cucumbers (3.20 ± 0.48 and 2.33 ± 0.25) on days 1 and 4, respectively. Between days 0 and 1, populations on control-treated cucumbers stored at 10 and 22°C declined by 1.07 and 2.47 log CFU per cucumber, respectively. At 22°C, Salmonella Newport populations declined by 2.37 log CFU per cucumber between days 0 and 1. Phage application to whole cucumbers before slicing did not reduce the transfer of Salmonella Newport to fresh-cut slices. Lytic phage application may be a potential intervention to reduce Salmonella populations on whole cucumbers.
authors.affiliation: 1 U.S. Department of Agriculture, Agricultural Research Service, Northeast Area, Environmental Microbial and Food Safety Laboratory, Beltsville, Maryland 20705.
authors.forename: Manan
authors.initials: M
authors.lastname: Sharma
authors.affiliation: 2 University of Maryland Eastern Shore, Department of Agriculture, Princess Anne, Maryland 21853.
authors.forename: Gwendolyn
authors.initials: G
authors.lastname: Dashiell
authors.affiliation: 1 U.S. Department of Agriculture, Agricultural Research Service, Northeast Area, Environmental Microbial and Food Safety Laboratory, Beltsville, Maryland 20705.
authors.forename: Eric T
authors.initials: ET
authors.lastname: Handy
authors.affiliation: 1 U.S. Department of Agriculture, Agricultural Research Service, Northeast Area, Environmental Microbial and Food Safety Laboratory, Beltsville, Maryland 20705.
authors.forename: Cheryl
authors.initials: C
authors.lastname: East
authors.affiliation: 2 University of Maryland Eastern Shore, Department of Agriculture, Princess Anne, Maryland 21853.
authors.forename: Russell
authors.initials: R
authors.lastname: Reynnells
authors.affiliation: 2 University of Maryland Eastern Shore, Department of Agriculture, Princess Anne, Maryland 21853.
authors.forename: Chanelle
authors.initials: C
authors.lastname: White
authors.affiliation: 3 University of Delaware, Department of Animal and Food Sciences, Newark, Delaware 19716.
authors.forename: Esmond
authors.initials: E
authors.lastname: Nyarko
authors.affiliation: 4 Department of Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland 20742, USA.|5 Center for Food Safety and Security Systems, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Shirley
authors.initials: S
authors.lastname: Micallef
authors.affiliation: 2 University of Maryland Eastern Shore, Department of Agriculture, Princess Anne, Maryland 21853.
authors.forename: Fawzy
authors.initials: F
authors.lastname: Hashem
authors.affiliation: 1 U.S. Department of Agriculture, Agricultural Research Service, Northeast Area, Environmental Microbial and Food Safety Laboratory, Beltsville, Maryland 20705.
authors.forename: Patricia D
authors.initials: PD
authors.lastname: Millner
mesh_terms: D001435:Bacteriophages; D015169:Colony Count, Microbial; D018553:Cucumis sativus; D005516:Food Microbiology; D012475:Salmonella; D012483:Salmonella Phages; D019779:Salmonella enterica
keywords: Bacteriophages; Cucumbers; Fresh-cut; Newport; Produce; Salmonella