(CDC)

Health officials have traced an outbreak of listeria in pre-packaged caramel apples that killed three people and sickened 29 more to a California apple distributor, the Food and Drug Administration announced Saturday.

The distributor, Bidart Brothers of Bakersfield has recalled all Granny Smith and Gala apples shipped from its Shafter, Calif. packing plant and still available for sale anywhere. The last shipment of Granny Smith apples from the facility went out on Dec. 2, the company said in a news release.

Three companies that make packaged caramel apples--Happy Apple Co. of Washington, Mo.; California Snack Foods, of El Monte, Calif.; and Merb’s Candies of St. Louis, Mo.--have previously recalled those products. There is no evidence of listeria in hand-dipped caramel apples, such as those available at fairs.

The FDA said tests of the listeria bacteria collected at the Bidart Brothers facility showed that it matched strains isolated from people who fell ill during the outbreak. Additional tests found listeria on Bidart Brothers whole  apples collected along the company's distribution chain.

Listeria is ubiquitous in the environment. It can live in food processing plants, even in cold temperatures, such as those in refrigerators, but is killed by cooking and pasteurization. It is also found in soil and water and in animals such as poultry and cattle.

In the current outbreak, 32 people fell ill in 11 states, and 31 required hospitalization. Ten of the illnesses were connected to pregnant women, one of whom lost a fetus as a result. Older adults, pregnant women, newborns and people with weakened immune systems are particularly vulnerable to listeriosis, the disease caused by the bacteria.

In 2011, listeria in cantaloupes killed 33 people and sickened 147 in 28 states, according to the Centers for Disease Control and Prevention. In 2012, 22 people were infected and four died in an outbreak attributed to a brand of ricotta cheese imported from Italy, the agency said.

Canadian public health officials are investigating two cases of listeriosis caused by bacteria with the same genetic fingerprint as the one found in the United States, but they have not yet determined the source of the bacteria, the FDA said.