(May 30) BANGKOK, Thailand — If a proposed U.S. Department of Agriculture rule is approved, Thailand will be the first country to export irradiated fruit to the U.S.

The proposal includes six Thai fruits — lychee, longan, mango, mangosteen, pineapple and rambutan — that could enter the U.S. market within the year.

Irradiation — a method that sterilizes fruit to protect it from fruit flies — was finalized as a commodity treatment in 2005 by the USDA. Other methods such as fumigation, baker heat, coal heat and vapor heat don’t meet standards for U.S. fresh fruit imports from Thailand.

The regulation is expected to publish within the next two months, said Jane Levy, associate executive director of plant health programs for the USDA’s Animal and Plant Health Inspection Service.

After it’s published, the rule is up for 60 days of public comment. Levy said she doesn’t expect many negative comments on the irradiation method.

Consumers haven’t been hesitant to purchase irradiated fruit from Hawaii, she said.

At the retail level, each piece of irradiated fruit will be labeled with an indication that it’s received that treatment, said Roger West, director of the Agricultural Safeguarding Office of Field Operations for U.S. Customs and Border Protection.

Both the Thai government and the private sector are developing irradiation treatment plants, which USDA officials plan to visit in June, Levy said.

As the first country to request that irradiated fruit be considered for admission into the U.S., Thailand could serve as a model, she said, adding that the USDA was counting on the country being a “shining example.”

Thai fruit exporters should be prepared to follow several guidelines for the new method, including inspections, labeling and packaging.


If the proposal goes into effect, an agreement between APHIS, Plant Protection and Quarantine and the National Plant Protection Organization will be made to outline the amount and type of inspections and how much monitoring will be required. The operator of the irradiation facility also must agree to these requirements, and the facility must be APHIS-certified.

The plant protection organization will monitor these requirements, Levy said.

  • A minimum dose of 400 grays of irradiation must be applied to the fruit during treatment, she said. Dosimetry mapping is required to ensure proper dosage;

  • Treated and untreated fruit must remain separate, and the treated fruit protected from re-infestation;

  • Inspections are required before and after irradiation treatment. And highly infested fruit won’t be treated with irradiation;

  • Inspections may be required in Thailand or at the U.S. port of entry;

  • A pre-clearance operational work plan must be in effect before any irradiated fruit is cleared for export to the U.S. This will map out who does what and how to verify the treatment is applied correctly, Levy said. The pre-clearance plan will be reviewed annually;

  • Fruit needs to be in the carton it will be shipped in during the irradiation treatment, and cartons must be either strapped or wrapped in order to remain as a unit;

  • At the carton level, holes must be covered with screens to prevent flies from getting back in post-treatment or the fruit must be stored in a room safeguarded from pests. If the latter method is selected, a shrink wrap or netting must be used after cartons are taken out of the room to avoid reinfestation;

  • The U.S. Food and Drug Administration mandates that each carton of treated fruit be marked, “Treated by Irradiation.” One label per pallet also must contain the treatment lot number and the identification and location of the packing and treatment facility;

  • A plant protection organization-issued phytosanitary certificate also is required for every shipment of irradiated material. On the U.S. side, an importer’s permit is necessary, but it’s an easy process that can be done online once the rule is finalized, Levy added; and

  • An additional declaration is needed to prove that lychee is free of Peronophythora litchi, a fungus common on lychee that irradiation doesn’t eliminate, she said.