As the Vermont law Consumer Protection Rule # 121 comes into effect July 1, 2016, all food products containing genetically modified organisms (GMO) must be labeled accordingly or face a hefty fine. Food items containing less than 0.9% of GMO ingredients do not have to be labeled.
This is true both for all foods grown in Vermont and foods shipped into Vermont. Thus, the burden of checking and labeling rests with distributors and retailers.
The food industry has a grace period of 6 months. After January 1, 2017, non compliance can be costly. Accordingly, many US importers and their distribution customers are asking their foreign suppliers to send a Letter of Guarantee or Affidavit.