Assisting Specialty Crop Exports: Low Oxygen Storage and Packaging Systems for U.S. Tree Nuts with Phytosanitary Traceability

The occurrence of insects as well as pesticide residuals can be significant barriers for U.S. horticultural exports. Each importing country can have unique phytosanitary and maximum residue limit (MRL) requirements, which creates operational and logistical challenges. To maximize return to growers, U.S. shippers need tools that can universally address all such requirements while maintaining product quality. Currently, tree nuts and many other durable specialty crops require fumigations or freezing, which are both expensive and create bottlenecks in marketing. More and more tree nut handlers are using a modified atmosphere (MA) or controlled atmosphere (CA) technology in which low-oxygen conditions (<1% by volume) are maintained during storage and/or in packaging. Low-oxygen conditions are known to control insect pests, leave no chemical residuals, and result in high quality products since the lipid oxidation that causes rancidity is markedly suppressed. While this approach is being used as a condition of sale, there is currently no efficient way for shippers to validate the low-oxygen conditions for customers, let alone importers with phytosanitary requirements for insect control. Technically and economically viable, verifiable, and preferably traceable technologies are critically needed before low-oxygen storage and packaging approaches can be used for export to most countries. Currently, the existing low-oxygen technologies do not incorporate digital mapping or official record-keeping during the packing or storage process, so there is no non-invasive manner to verify the oxygen content over time within the gas-impermeable liners and/or confirm seal integrity. This limits the ability to verify that a low-oxygen environment has been maintained at a specific oxygen level over a certain period of time, which would be necessary to ensure the conditions were met to act as a phytosanitary treatment. Counties such as India, Korea, and Japan require phytosanitary treatments, such as fumigation, for post-harvest pest management before many types of U.S. tree nuts can be imported into the countries. Additionally, buyers in other markets also request pest management treatments as a condition of sale in commercial transactions.