A US distributor of peanut butter has recalled two brands after discovering one of the products was contaminated with salmonella.

King Nut Cos., which handles peanut butter made for the business by manufacturer Peanut Corp., said salmonella had been found in an open five-pound tub of King Nut peanut butter.

King Nut said its customers should remove all namesake peanut banner and a second brand, Parnell's Pride, out of distribution immediately.

The recall comes amid a nationwide salmonella outbreak, which has caused 399 people in 42 US states to fall ill.

The source of the outbreak is still to be identified with the Centers for Disease Control and Prevention and the US Food and Drug Administration working to determine the origin of the contamination.

"The FDA is collaborating with CDC, the US Department of Agriculture, and public health officials in many states to investigate an ongoing, multi-state outbreak of human infections due to Salmonella serotype Typhimurium," a spokesperson for the FDA told just-food today (12 January).

"There is insufficient information at this time to conclusively link King Nut Peanut Butter to the national outbreak of Salmonella serotype Typhimurium. However, the FDA is working with that distributor to ensure that all the recalled products are removed from the market and to find the source of the contamination from that product."

King Nut president and CEO Martin Kanan said the company was "very sorry" about the contamination.

"We are taking immediate and voluntary action because the health and safety of those who use our products is always our highest priority."