| heal.abstract |
Maintaining product quality is critical for success in fresh fruit and vegetable marketing. Some onion packinghouses are considering the addition of x-ray inspection systems to their existing optical inspection systems. X-ray systems enable detection of voids that are likely to be associated with the presence of various bacterial or fungal rots in onions. A series of tests were conducted at the University of Georgia Vegetable and Vidalia Onion research and education center in Toombs County, Georgia, with a commercially available x-ray inspection machine. In 2001, two 100-onion batches of medium-sized onions and 100 jumbo onions were machine-inspected, and then halved for a visual internal evaluation. In each series of tests, the accuracy rate was greater than 93% and the false positives were less than 6%. In 2002, two 100-onion batches were run on a similar machine as in 2001. Additionally, in 2002 and 2004, multiple onions with slight to severe defects were each passed through the inspection machine 50 times, respectively, with orientation not controlled to ascertain consistency in defect detection. The machine passed onions with no to slight defect presence (based on subsequent internal visual evaluation of onion halves) nearly 100% of the time. Onions with severe defects were rejected 100% of the time. In 2004, a center rot disease (caused by Pantoea ananztis) study showed that 80% of bulbs that had passed a routine surface inspection and had been deemed to be diseased by the machine in fact exhibited the disorder on halving. False positives were in the 10% to 15% range. In the 2002 and 2004 studies, the machine detected bulbs with disease that passed human visual inspection (HVI) and (in 2004 only) individual tactile grading. These accuracy and false positive rates are very close to the 90% and 10% levels generally accepted for these respective statistics. With appropriate addition of multiple lanes, commercially viable throughputs are possible. © 2005 American Society of Agricultural Engineers. |
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