It seems Queen Elizabeth II has a taste for Tabasco.

McIlhenny Co., which produces the fiery pepper sauce, has gone to great lengths to document the fact that its product is stocked in the Buckingham Palace pantry. The company’s efforts have earned it the ultimate royal seal of approval. McIlhenny will become one of a few U.S. companies to receive a Royal Warrant of Appointment that distinguishes it as a supplier to the queen.

Royal warrants are given to individuals or companies who have supplied goods or services to the queen for at least five years. Prince Philip and Prince Charles grant separate warrants. The British royal family tradition began in 1155.

“I think it’s an honor, an international cache that is recognized, certainly in the United Kingdom but even around the world,” said Paul McIlhenny, president of the company.

Earning the royal warrant was no small feat. McIlhenny, like many companies its size, distributes its product through a sequence of vendors and retailers, which makes it difficult to pinpoint exactly where Tabasco ends up.

McIlhenny executives had heard rumors the red sauce was used at Buckingham Palace, but they hadn’t confirmed its presence. To qualify for a Royal Warrant of Appointment, the company needed rock-solid proof.

McIlhenny said his company was able to obtain verification that included affidavits and sales invoices attesting to Tabasco’s presence in Buckingham Palace.

“It was a key purveyor that authenticated our sales to the royal household,” McIlhenny said.

Still, documenting itself as a supplier wasn’t enough. To earn the warrant, McIlhenny also had to pass a rigorous review that included an assessment of its environmental record and its efforts to operate sustainably.

McIlhenny joins 850 companies around the world that have been designated as suppliers to the queen. The list includes broom and saddle makers, distillers, fabric dealers, ham and bacon suppliers, handbags craftsmen, fish dealers and even nosegay makers.

In November, Paul McIlhenny will travel to London for a banquet honoring new members of the Royal Warrant Holders Association. His company plans to begin marketing its sauce in Britain with a label that reads “By Appointment to Her Majesty Queen Elizabeth II.”

Tabasco sauce, created in 1868, is still produced at Avery Island, where the peppers are grown, harvested and then fermented in white oak barrels before being bottled and shipped.

The product was first sold in Britain in 1874.