(UPDATED COVERAGE, 4 p.m., July 24)

Tanimura & Antle has expanded its voluntary recall on bulk and wrapped romaine head lettuce due to possible salmonella contamination to all 50 states, according to the company’s Web site.

UPDATED: Tanimura & Antle expands lettuce recall

Amy Philpott, vice president of communications with Watson/Mulhern LLC, a Washington, DC-based public relations form hired by Tanimura & Antle, said the recall was expanded based on information Tanimura & Antle received from its customers about possible distribution beyond the 29 states involved in the initial recall July 20.

“What we found out from some of those customers is they have distributed the product beyond the original states,” Philpott said.

For photos of the recalled items, visit www.taproduce.com/press.

Philpott said the volume of product recalled hasn’t changed only the distribution area and the company is being extra cautious even though all recalled product is out of distribution.

The source and cause of the contamination is still unknown, Philpott said.

Donna Gilson, a public information officer with Wisconsin Department of Agriculture, Trade and Consumer Protection, said in an e-mail the romaine, collected from a distribution center, was tested on July 14, one day after the department purchased the one carton. Gilson said six heads were tested and one "had a positive result" and five were negative. The department received confirmation of the positive test July 20 and notified Tanimura & Antle the same day.

The testing was part of a contract the department has with U.S. Department of Agriculture and there is no further testing being done to determine the cause or source of contamination, Gilson said.