Tracking peanuts, soil to processor

This information is based on interviews late last week with John Beasley, professor of crop and soil sciences and peanut agronomist at the University of Georgia (based in Tifton); and Michael Doyle, Regents professor of food microbiology at UGA and director of the Center for Food Safety. It also includes information from the New Georgia Encyclopedia, and from AJC files.

> Georgia peanuts typically are planted in May and spend 140 days on average growing into mature plants. They thrive in Georgia’s sandy soils and subtropical climate, making the state the No. 1 peanut producer in America.

> The plants flower above ground, but they bear fruit underground. To harvest them, farmers use a device known as a digger-shaker-inverter, which slips under the plant, lifts it out of the ground, shakes off the soil and flips it over, so the peanuts are facing up, toward the sun.

> At this point, the insides of the peanut shell, or pod, are 40 percent water. The pods are left to cure in the sun for about three days, during which time the moisture content declines to between 12 to 18 percent.

> Now the farmer uses a combine to separate pod from vine, and harvests the pods. One acre typically produces more than 3,000 pounds of peanuts. The farmer hauls the harvested nuts to a “buying point” to be graded and sold to shellers.

> The shellers haul the peanuts by semi-truck to warehouses or directly to shelling plants, where machines remove the hulls and render the kernel, or what we call the nut. The shellers then sell the shelled peanuts to processors.

> Processors put shelled nuts into roasters. These machines cook peanuts at 250 to 300 degrees for 15 to 30 minutes —- a process that salmonella bacteria cannot survive. Peanut Corp. of America in Blakely is a peanut processor. The Food and Drug Administration report on the company states that “this firm has not established the effectiveness of the temperature, volume or belt speed specific to this roaster to assure it is adequate as a kill step for pathogenic bacteria.”

> Once the roasting is complete, the processor must take care to keep the cooked peanuts segregated from raw ones. They may not come into contact with any raw material, or dust from raw material, or equipment that has been exposed to raw material. Otherwise, the processor risks undoing the purifying work done by the roasters.

Salmonella and peanuts

> Salmonella is a group of bacteria that cause diarrheal illness in people. They originate in the intestines of people and animals and pass from feces to other people or other animals, causing a malady known as salmonellosis.

> Salmonella may come into contact with crops in a variety of ways. Perhaps a farmer fertilizes with manure. Perhaps a wild animal leaves feces in a field. You may recall the spinach scare of 2006, in which feral pigs’ feces contaminated spinach leaves in California with E. coli. Another potential source: the water used for irrigation. Salmonella is remarkably stable in dry conditions and can live on or in the ground for months or even years.

> A 2007 salmonella outbreak at a ConAgra Foods plant in Sylvester, Ga., resulted in a recall of Peter Pan peanut butter and sickened hundreds of people nationwide. The culprit later was identified as a leaky roof and a faulty sprinkler system that rained water down on peanuts after they had been through the roaster. The plant later underwent $20 million in renovations and reopened.

> The FDA report on the Peanut Corp. of America (below) outbreak notes 12 occasions on which salmonella contamination was detected on the company’s products in 2007 and 2008. “After the firm retested the product and received a negative status, the product was shipped in interstate commerce,” the FDA said of all 12 instances.