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Differentiation of Volatile Profiles from Stockpiled Almonds at Varying Relative Humidity Levels Using Benchtop and Portable GC-MS

Beck John J., Willett Denis S., Gee Wai S., Mahoney Noreen E., Higbee Bradley S.
Journal of agricultural and food chemistry 2016 v.64 no.49 pp. 9286-9292
Aspergillus, aflatoxins, almonds, biomarkers, fungal spores, fungi, gas chromatography-mass spectrometry, metabolites, microbial growth, orchards, pistachios, relative humidity, solid phase microextraction, toxicity, volatile compounds, water activity, California
Contamination by aflatoxin, a toxic metabolite produced by Aspergillus fungi ubiquitous in California almond and pistachio orchards, results in millions of dollars of lost product annually. Current detection of aflatoxin relies on destructive, expensive, and time-intensive laboratory-based methods. To explore an alternative method for the detection of general fungal growth, volatile emission profiles of almonds at varying humidities were sampled using both static SPME and dynamic needle-trap SPE followed by benchtop and portable GC-MS analysis. Despite the portable SPE/GC-MS system detecting fewer volatiles than the benchtop system, both systems resolved humidity treatments and identified potential fungal biomarkers at extremely low water activity levels. This ability to resolve humidity levels suggests that volatile profiles from germinating fungal spores could be used to create an early warning, nondestructive, portable detection system of fungal growth.