At least 42 people, including four in the Portland area, have become infected with salmonella from eating pepper, Oregon health authorities said today.

The pepper was traced to Union International Food Co. in the San Francisco Bay Area, which sells spices in bulk to markets and restaurants.

Many of the people sickened, including those in the Portland metro area, ate at Asian restaurants, which helped epidemiologists trace the source of the contamination.

"Spices are not the easiest thing to figure out," said William Keene, senior epidemiologist at the Public Health Division in Oregon, because they are used in so many ways.

He said all of the cases in the metro area were linked to Asian restaurants or markets. He said three Asian restaurants appeared to be involved, two on the east side of Portland and one in the greater metropolitan area. He would not give the names of the restaurants but said he had eaten at two of them.

The outbreak spans four states, with 33 cases in California, four in Oregon, one in Washington and four in Nevada. There are two more likely cases in California, Keene said.

One cluster of people from California and Nevada ate at the same buffet-style restaurant at a casino in Reno, Nev., that also bought spices from Union International Food Co.

The company recalled 18 spices sold under the Lian How brand in different size containers. The recalled spices include various forms of white and black pepper, cayenne pepper, paprika, chopped onion, onion powder, various forms of garlic, curry powder, mustard powder and wasabi powder.

Although the company initiated a wide recall, Keene said that white pepper is the likely culprit in the outbreak, which appears to have started last year. The company sold spices wholesale under the Lian How brand. It is not clear whether the company sold another brand, Uncle Chen, to retail stores, Keene said.

Not all of the people suffered severe symptoms. In fact, one of those infected in the Portland area did not develop gastro-intestinal symptoms associated with a salmonella infection, such as vomiting or diarrhea, but found out through a urine tests for another reason.

It's not clear how the pepper was contaminated. Salmonella is present in animal feces, for example from birds or rats.

This is not the first salmonella outbreak linked to spices. Keene said there was another outbreak in Norway in the 1980s caused by contaminated pepper.

Consumers with questions may contact Union International Food Co. at 510-471-6799.