title: Inactivation of Salmonella enterica and Listeria monocytogenes in cantaloupe puree by high hydrostatic pressure with/without added ascorbic acid.
abstract: The objective of this research was to evaluate and develop a method for inactivation of Salmonella enterica and Listeria monocytogenes in cantaloupe puree (CP) by high hydrostatic pressure (HHP). Cantaloupe being the most netted varieties of melons presents a greater risk of pathogen transmission. Freshly prepared CP with or without 0.1% ascorbic acid (AA) was inoculated with a bacterial cocktail composed of a three serotype mixture of S. enterica (S. Poona, S. Newport H1275 and S. Stanley H0558) and a mixture of three strains of L. monocytogenes (Scott A, 43256 and 51742) to a population of ca. 10(8)CFU/g. Double sealed and double bagged inoculated CP (ca. 5g) were pressure treated at 300, 400 and 500MPa at 8°C and 15°C for 5min. Data indicated increased inactivation of both Salmonella and Listeria spp. with higher pressure. Log reduction for CP at 300MPa, 8°C for 5min was 2.4±0.2 and 1.6±0.5logCFU/g for Salmonella and Listeria, respectively. Survivability of the pathogens was significantly compromised at 400MPa and 8°C, inactivating 4.5±0.3logCFU/g of Salmonella and 3.0±0.4logCFU/g of Listeria spp. Complete inactivation of the pathogens in the puree (log reduction >6.7logCFU/g), with or without AA, was achieved when the pressure was further increased to 500MPa, except that for Listeria containing no AA at 8°C. Listeria presented higher resistance to pressure treatment compared to Salmonella spp. Initial temperatures (8 and 15°C) had no significant influence on Salmonella log reductions. Log reduction of pathogens increased but not significantly with increase of temperature. AA did not show any significant antimicrobial activity. Viable counts were about 0.2-0.4logCFU/g less in presence of 0.1% AA. These data validate that HHP can be used as an effective method for decontamination of cantaloupe puree.
authors.affiliation: Residue Chemistry & Predictive Microbiology Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, United States. Electronic address: Sudarsan.mukhopadhyay@ars.usda.gov.
authors.forename: Sudarsan
authors.initials: S
authors.lastname: Mukhopadhyay
authors.affiliation: Residue Chemistry & Predictive Microbiology Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, United States. Electronic address: Kimberly.sokorai@ars.usda.gov.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Sokorai
authors.affiliation: Food Safety Intervention Technology Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, United States. Electronic address: Dike.ukuku@ars.usda.gov.
authors.forename: Dike
authors.initials: D
authors.lastname: Ukuku
authors.affiliation: Residue Chemistry & Predictive Microbiology Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, United States. Electronic address: Xuetong.fan@ars.usda.gov.
authors.forename: Xuetong
authors.initials: X
authors.lastname: Fan
authors.affiliation: Residue Chemistry & Predictive Microbiology Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, United States. Electronic address: Vijay.juneja@ars.usda.gov.
authors.forename: Vijay
authors.initials: V
authors.lastname: Juneja
authors.affiliation: Food Safety Intervention Technology Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, United States. Electronic address: Joseph.sites@ars.usda.gov.
authors.forename: Joseph
authors.initials: J
authors.lastname: Sites
authors.affiliation: Food Safety Intervention Technology Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, United States. Electronic address: Jennifer.cassidy@ars.usda.gov.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Cassidy
mesh_terms: D000900:Anti-Bacterial Agents; D001205:Ascorbic Acid / Q000494:pharmacology; D015169:Colony Count, Microbial; D028463:Cucumis melo / Q000382:microbiology*; D004203:Disinfection / Q000379:methods*; D019453:Escherichia coli O157 / Q000502:physiology; D005516:Food Microbiology / Q000379:methods*; D006874:Hydrostatic Pressure; D008089:Listeria monocytogenes / Q000254:growth & development*; D019779:Salmonella enterica / Q000254:growth & development*; D013696:Temperature
chemical_list: D000900:Anti-Bacterial Agents; D001205:Ascorbic Acid
keywords: Antimicrobial; Cantaloupe puree; High hydrostatic pressure processing; Listeria monocytogenes; Salmonella enterica