From U.S. Dept. of Homeland Security, web page Bringing Agricultural Products Into the United States - CBP.gov
Certain items brought into the United States from foreign countries are restricted according to U.S. Department of Agriculture (USDA) regulations. Prohibited agricultural items can harbor foreign animal and plant pests and diseases that could seriously damage America’s crops, livestock, pets, and the environment – and a large sector of our country’s economy.
All travelers entering the United States are required to DECLARE any meats, fruits, vegetables, plants, seeds, animals, and plant and animal products (including soup or soup products) they may be carrying. The declaration must cover all items carried in checked baggage, carry-on luggage, or in a vehicle.
Upon examination of plants, animal products, and associated items, U.S. Customs and Border Protection (CBP) agriculture specialists at the ports of entry will determine if these items meet the entry requirements of the United States.
Even though an item may be listed as “permitted” from a particular country, it is always best to DECLARE the item by checking “Yes” on Question 11 of the CBP Declaration Form 6059B. Also declare if you have been on a farm or in close proximity of livestock, as an agriculture specialist may need to check your shoes or luggage for traces of soil that could harbor foreign animal diseases such as foot-and-mouth.
Avoid Fines and Delays
Prohibited items that are not declared by passengers are confiscated and disposed of by CBP agriculture specialists. But that’s not all. Civil penalties may be assessed for violations and may range up to $1,000 for a first-time offense. Depending on whether the confiscated, undeclared items are intentionally concealed, or determined to be for commercial use, civil penalties may be assessed as high as $50,000 for individuals. The same fines apply to prohibited agricultural products sent through the international mail.
Fruits, Vegetables, and Plants
Depending on the country of origin, some fruits, vegetables, and plants may be brought into the United States without advance permission, provided they are declared, inspected, and found free of pests. However, certain plants and ANY plant parts intended for growing (propagative) require a phytosanitary certificate in advance. For information on certificates, contact the USDA/APHIS Plant Protection and Quarantine Permit Unit. Also, check the Information Resources section at the end of this notice for details.
I believe the oranges you are talking about were coming from another country into the U.S.A. by a person heading to Canada. US customs agents gave the person carrying them a hard time due to the above stated guidelines.
I work for the Dept. of Ag in Idaho, food safety is becoming a big issue in this country. Believe it or not other countries are way stricter in what and how they let foreign produce into their country. When ever we write phytosanitary certificates to allow US produce into a foreign country we have to look in a data base for that country to see what guidelines must be followed before that product can be shipped out of the US to them. Things change all the time. These days the govt. is worried about terrorist causing problems through the food chain, for both economic and health reasons.