A company at the heart of a nationwide pistachio recall said Friday that Kraft Foods Inc. detected salmonella in its pistachios more than six months ago but did not inform them until last week.
A Kraft spokeswoman said the food products giant did not know until recently that pistachios were the cause of salmonella contamination in a trail mix and promptly informed their nut supplier, Setton Pistachio of Terra Bella, Inc.
Lee Cohen, a production manager for the California firm's sister plant, said Setton's pistachios tested positive for the bacteria in a Kraft snack mix in September 2008.
The tainted nuts were found in a blend of fruits and nuts that also contained salmonella-tainted cherries, he said.
Setton Pistachio recalled more than 2 million pounds of its roasted nuts on Monday after a Kraft manufacturer in Illinois detected salmonella in another batch of its pistachios on March 20.
The California plant never knowingly shipped contaminated nuts to Kraft, and its own tests of roasted pistachios never found salmonella, he said.
Cohen said Kraft did not tell Setton Pistachio of the September test until March 24.
Susan Davison, a Kraft spokeswoman, said their manufacturer Georgia Nut Co. first found the bacteria in its Kraft Back to Nature Nantucket Blend trail mix in September, but it took more than six months of careful ingredient testing to determine what caused the contamination.
Once Georgia Nut determined it was pistachios on March 20, the two companies issued a recall days later, she said.
Dr. David Acheson, FDA's assistant commissioner for food safety, said he believes Kraft destroyed or recalled the tainted trail mix. He said the FDA learned last week about the problems from six months ago.
Neither federal nor state laws require food manufacturers to test the safety of their products. If companies test and find contaminated food, they are also not required to report it, although many do if they plan to issue a recall, Acheson said.
On Monday, federal regulators issued a sweeping warning, telling the public not to eat any pistachios until further notice.
"Through September, November, Kraft found some positive samples and they started to say 'what is the cause of this?'" Acheson said. "If they find problems in a product prior to shipment, they'll pull it back and destroy it. I wouldn't call that a good manufacturing practice, but that is clearly a good public health practice."
Salmonella, the most common cause of food-borne illness, causes diarrhea, fever and cramping. Most people recover, but the infection can be life-threatening for children, the elderly and people with weakened immune systems.
Roasting is supposed to kill the bacteria in nuts. But problems can occur if the roasting is not done correctly or if roasted nuts are re-contaminated. That can happen if mice, rats or birds get into the facility.
Cohen said Friday that some of Setton Pistachio's internal tests had detected salmonella on its own raw pistachios in the past. He did not say when, but said all tainted pistachios were later roasted.
"We have found salmonella on raw pistachios, but that doesn't mean anything because those nuts are coming straight from the orchards where you could have had a very small localized contamination from birds," Cohen said. "Those nuts never hit the marketplace."
The Long Island sister firm is one of 36 wholesale customers that gets its nuts from the California plant. On Friday, Setton International Foods announced it was voluntarily recalling about 118,000 pounds of pistachio products.