
A Ratio Process Makes It Easier To Detect
Aflatoxin LevelsBy Sarah
Tarshis July 12, 1999One bad nut can spoil the whole bunch,
thanks to aflatoxin, a carcinogen that can contaminate peanuts and other
commodities. Federal food safety regulations create a need to find the most
efficient aflatoxin detection method possible. Such methods can be
time-consuming and expensive. So Thomas B. Whitaker of the Agricultural
Research Service has been researching methods of accurately estimating
aflatoxin levels in peanut lots to better ensure appropriate handling. He
developed a new method of detection that may reduce economic loss for handlers
and farmers while also preserving quality. Whitakers method of detecting aflatoxin in a lot is to measure the
aflatoxin levels in the high-risk peanuts. Peanuts that are damaged, loose
shelled or small are labeled high-risk. An estimated ratio of aflatoxin in
high-risk peanuts to aflatoxin in the lot determines the aflatoxin of the
entire lot. Whitaker found that a five-to-one ratio accurately assesses the
aflatoxin levels. For example, if a high-risk sample has an aflatoxin
contamination level of 100 parts per billion (ppb), the entire truckload will
probably average 20 ppb--the Food and Drug
Administrations legal limit for food quality safety. The ratio was
derived over a wide range of concentration in many lots, according to Whitaker.
The current method of detecting aflatoxin in peanuts can cause farmers and
handlers to lose profits because of inaccuracy. When a truckload of peanuts is
brought from a farm to the buyer, it is sampled and visually examined for moldy
kernels that indicate the lot may be contaminated by aflatoxin. If even one
moldy kernel is found, the entire truckload is classified as a low-grade status
that could result in profit loss. The ratio method might be used to replace or
complement the current method of visual analysis. A story on the research is in the July issue of Agricultural Research magazine
and on the web at: http://www.ars.usda.gov/is/AR/archive/jul99/pea0799.htm Scientific contact: Dr.
Thomas B.
Whitaker, ARS Market Quality
and Handling Research Unit, Raleigh, N.C.; phone (919) 515-6731, fax (919)
515-7760, [email protected]. U.S. Department of Agriculture | |