title: Silo-Stored Pistachios at Varying Humidity Levels Produce Distinct Volatile Biomarkers.
abstract: Fungal-contaminated tissues are known to produce volatile profiles that are different from uncontaminated tissues. Fungi require certain water activity levels before growth can occur. For nonxerophilic fungi, a water activity of 0.85 is typical for growth, and for extreme xerophilic fungi, the water activity can be as low as 0.64. Recent investigations with stored pistachios (kernels in shell, no hull tissue) at varying relative humidities showed differences among the collected volatile profiles at the tested humidities (ambient, 63, 75, and 84%). Water activities of the kernel and shell were also measured. Results showed significant changes in volatile profiles as a function of water activity of the corresponding pistachio tissue with measured water activity levels at or below that of what is considered extreme xerophilic activities. Because fungal growth, including mycotoxigenic fungi, is dependent upon water activity, the detected volatile profiles could be used for early detection of fungal presence. Multivariate analysis of the volatile data demonstrated significant differences among the volatile profiles at the tested relative humidity levels, and several volatiles were identified as biomarkers of increased humidity and likely fungal development.
authors.affiliation: Chemistry Research Unit, Center for Medical, Agricultural and Veterinary Entomology , Agricultural Research Service, U.S. Department of Agriculture, 1700 SW 23rd Drive, Gainesville, Florida 32608, United States.
authors.forename: John J
authors.identifier: http://orcid.org/0000-0002-0696-5060
authors.initials: JJ
authors.lastname: Beck
authors.affiliation: Chemistry Research Unit, Center for Medical, Agricultural and Veterinary Entomology , Agricultural Research Service, U.S. Department of Agriculture, 1700 SW 23rd Drive, Gainesville, Florida 32608, United States.
authors.forename: Denis S
authors.initials: DS
authors.lastname: Willett
authors.affiliation: Foodborne Toxin Detection and Prevention, Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture , 800 Buchanan Street, Albany, California 94710, United States.
authors.forename: Noreen E
authors.initials: NE
authors.lastname: Mahoney
authors.affiliation: Foodborne Toxin Detection and Prevention, Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture , 800 Buchanan Street, Albany, California 94710, United States.
authors.forename: Wai S
authors.initials: WS
authors.lastname: Gee
mesh_terms: D005506:Food Contamination / Q000032:analysis*; D061353:Food Storage; D005658:Fungi / Q000254:growth & development / Q000378:metabolism*; D006813:Humidity; D027927:Pistacia / Q000737:chemistry / Q000382:microbiology*; D012639:Seeds / Q000382:microbiology; D055549:Volatile Organic Compounds / Q000737:chemistry* / Q000378:metabolism; D014867:Water / Q000032:analysis / Q000378:metabolism
chemical_list: D055549:Volatile Organic Compounds; D014867:Water
keywords: detection; fungal spore; percent moisture; volatile production; water activity