Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/12/1999
Publication Date: N/A
Interpretive Summary: Sporadic contamination of corn and other grains with mycotoxins, from fungi such as Aspergillus flavus and Fusarium moniliforme, which cause deadly diseases in humans and animals is a major problem facing American agriculture. Contamination of corn grain is chronic in warm, humid areas where conditions are favorable for growth of Aspergillus flavus which produces aflatoxin B1, one of the most potent natural carcinogens yet discovered. In addition to the health hazard, substantial economic loss results when grain destined for commodity markets is devalued due to toxic fungal contamination. Consequently, there is an urgent need to develop rapid and efficient testing methods to reduce the extent of fungal infestation of grains and thus lower the levels of toxins in the food and feed supply. Experiments are underway at NCAUR to develop nondestructive infrared sensors to monitor corn grain for Aspergillus flavus and Fusarium moniliforme at grain elevators and other off-farm locations. Transient infrared spectroscopy (TIRS) is a promising new technique that can detect fungal infection in corn grain moving on production lines at conveyor belt speed. Preliminary test results using TIRS predict an 85-95% success rate in distinguishing healthy corn from grain infected with Aspergillus flavus.
Technical Abstract: An urgent need for rapid sensors to detect contamination of food grains by toxigenic fungi such as Aspergillus flavus prompted investigation of Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) as a highly sensitive probe for fungi growing on the surfaces of individual corn kernels. However, the photoacoustic technique has limited potential for screening bulk corn because currently available photoacoustic detectors can accommodate only a single kernel at a time. Transient infrared spectroscopy (TIRS), on the other hand, is a promising new technique that can acquire analytically useful infrared spectra from a moving mass of solid materials. Therefore, the potential of TIRS for on-line, noncontact detection of A. flavus contamination in a moving bed of corn kernels was explored. Early test results using TIRS predict an 85-95% success rate in distinguishing healthy corn from grain infected with A. flavus. Infrared spectral features that identified infected corn in FTIR-PAS were also found to be diagnostic in TIRS.