Rapid, Non-Invasive, and Early Warning Detection of Mycotoxigenic Aspergilli on Almonds and Pistachios in Holding, Storage, and Transit
Foodborne Toxin Detection and Prevention
Project Number: 5325-42000-037-13
Start Date: Oct 01, 2012
End Date: Jun 30, 2015
Aflatoxin contamination of almonds and pistachios results in millions of dollars of lost product annually. Aflatoxins are metabolites produced by Aspergillus flavus and A. parasiticus, ubiquitous fungi of California tree nut orchards, and represent a grave food safety problem due to their carcinogenic attributes. Current methods of analysis involve removal and destruction of 20 kilograms of product, utilize laboratory-based methods (e.g. HPLC), are expensive, and can take weeks for results. Because aflatoxin contamination can be limited to one- or two-highly contaminated nuts, current methods do not guarantee detection of the infected nuts, thus posing serious health and safety concerns for the public.
Importance and timeliness: Despite an increase in self-regulation and aflatoxin testing protocols by the almond and pistachio industry, the costly rejection of exported product continues. A reliable, early warning aspergilli detector has been cited as a critical need of the industry. The current project has the strong support of both the Almond Board of California and the California Pistachio Research Board of California.
Objectives: Continue investigation of recently discovered volatile profile of germinating aspergilli spores on almond and pistachio, including volatile compounds unique to the germinating spores on these hosts; use volatile profile in conjunction with a portable GCMS system to develop a near real time portable field volatile sampling device capable of early warning detection of aspergilli infected almond and pistachio; remove aflatoxin-producing aspergilli “hot spots” from almond and pistachio stockpiles and transit containers thus decreasing human health risks and product loss as a result of Aspergillus contamination.
Commitment of USDA Resources: Partial commitment of instruments and equipment for completion of project including: GC-MS, safety hoods, GC-FID, HPLC, and LC-MS. All instruments are present in SYs’ laboratories. Partial time commitment of scientist in the SY’s laboratory.
For first objective – continue investigation of recently discovered volatile profile of germinating aspergilli spores on almond and pistachio, including volatile compounds unique to the germinating spores on these hosts – current and preceding research has identified volatile markers of early spore germination from components of almond and pistachios. Additionally, many of these markers have been detected on the hulls of almonds. Research investigating the conditions for emission of the volatile makers will continue for the first year of the grant.
For second objective – use volatile profile in conjunction with a portable GCMS system to develop a near real time portable field volatile sampling device capable of early warning detection of aspergilli infected almond and pistachio – an agreement is being formed with a portable GCMS company (Torion Technologies, Inc., the co-project director of the grant proposal) to develop a volatile collection device fitting that will connect to an existing portable GCMS. Torion Technologies will also develop the necessary software for identifying multiple signals from the contaminated almond and pistachio.
For the third objective – remove aflatoxin-producing aspergilli “hot spots” from almond and pistachio stockpiles and transit containers – using the maker volatile profiles discovered by the USDA-ARS lab, apply the developed portable GCMS system to simulated and actual field conditions for detecting inoculated/contaminated almond and pistachio product.