Kiwis planning to go on their OE, be warned: Your beloved Vegemite might be confiscated if you travel to the United States.

An Australian has revealed that US border security police questioned him recently on suspicion of carrying Vegemite into the country.

The yeasty spread is banned because it contains folate, which in the US can be added only to bread and other grain products such as cereal.

Daniel Fogarty told the Geelong Advertiser that he was amazed when he and his partner Sarah Egan, who live in Canada, were asked if they had any Vegemite at a border crossing between the two countries.

"We were completely shocked. Normally Sarah wouldn't travel far without Vegemite but for some reason we didn't have it."

A spokeswoman for Kraft Foods in Australia told the Herald last night that the rule was "very annoying".

"Australians love Vegemite, but only a small number of people in the US actually eat it."

She said the company had stopped exporting Vegemite to the US in the past year, but wasn't sure how long Vegemite had been banned in the US.

"We have to respect the regulations and that means we can't export it to the US."

There was no issue with the safety of Vegemite. A folate-free variety was "a nice idea" but impractical given how few people in the US ate it.

Paul Watkins, who owns a shop selling Australian goods in San Antonio, Texas, told the Sunday Mail he had been forced to stop importing Vegemite six months ago.

Three companies in the US selling Australian goods online were yesterday still advertising Vegemite on their websites.

Folate, a B vitamin, plays a critical role in cell division, prevents birth defects and cuts heart disease.