title: Survival of Salmonella during Drying of Fresh Ginger Root (Zingiber officinale) and Storage of Ground Ginger.
abstract: The survival of Salmonella on fresh ginger root (Zingiber officinale) during drying was examined using both a laboratory oven at 51 and 60°C with two different fan settings and a small commercially available food dehydrator. The survival of Salmonella in ground ginger stored at 25 and 37°C at 33% (low) and 97% (high) relative humidity (RH) was also examined. To inoculate ginger, a four-serovar cocktail of Salmonella was collected by harvesting agar lawn cells. For drying experiments, ginger slices (1 ± 0.5 mm thickness) were surface inoculated at a starting level of approximately 9 log CFU/g. Higher temperature (60°C) coupled with a slow fan speed (nonstringent condition) to promote a slower reduction in the water activity (aw) of the ginger resulted in a 3- to 4-log reduction in Salmonella populations in the first 4 to 6 h with an additional 2- to 3-log reduction by 24 h. Higher temperature with a higher fan speed (stringent condition) resulted in significantly less destruction of Salmonella throughout the 24-h period (P < 0.001). Survival appeared related to the rate of reduction in the aw. The aw also influenced Salmonella survival during storage of ground ginger. During storage at 97% RH, the maximum aw values were 0.85 at 25°C and 0.87 at 37°C; Salmonella was no longer detected after 25 and 5 days of storage, respectively, under these conditions. At 33% RH, the aw stabilized to approximately 0.35 at 25°C and 0.31 at 37°C. Salmonella levels remained relatively constant throughout the 365-day and 170-day storage periods for the respective temperatures. These results indicate a relationship between temperature and aw and the survival of Salmonella during both drying and storage of ginger.
authors.affiliation: U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 6502 South Archer Road, Bedford Park, Illinois 60501, USA.
authors.forename: Dana R
authors.initials: DR
authors.lastname: Gradl
authors.affiliation: Illinois Institute of Technology, Institute for Food Safety and Health, 6502 South Archer Road, Bedford Park, Illinois 60501, USA.
authors.forename: Lingxiang
authors.initials: L
authors.lastname: Sun
authors.affiliation: U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 6502 South Archer Road, Bedford Park, Illinois 60501, USA; Center for Medical Mycology, 11100 Euclid Avenue, LKS-5028, Cleveland, OH 44106-5028, USA.
authors.forename: Emily L
authors.initials: EL
authors.lastname: Larkin
authors.affiliation: U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 5100 Paint Branch Parkway, College Park, Maryland 20740, USA.
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Chirtel
authors.affiliation: U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 6502 South Archer Road, Bedford Park, Illinois 60501, USA. susanne.keller@fda.hhs.gov.
authors.forename: Susanne E
authors.initials: SE
authors.lastname: Keller
mesh_terms: D015169:Colony Count, Microbial; D003890:Desiccation; D005511:Food Handling / Q000295:instrumentation / Q000379:methods*; D061353:Food Storage; D020939:Zingiber officinale / Q000737:chemistry / Q000382:microbiology*; D006358:Hot Temperature; D012475:Salmonella / Q000254:growth & development* / Q000302:isolation & purification; D017365:Spices / Q000032:analysis / Q000382:microbiology; D014867:Water / Q000032:analysis
chemical_list: D014867:Water