Gordon S H, Schudy R B, Wheeler B C, Wicklow D T, Greene R V
U.S. Department of Agriculture, Agricultural Research Service, Peoria, IL 61604, USA.
Int J Food Microbiol. 1997 Apr 1;35(2):179-86. doi: 10.1016/s0168-1605(96)01217-2.
Aspergillus flavus and other pathogenic fungi display typical infrared spectra which differ significantly from spectra of substrate materials such as corn. On this basis, specific spectral features have been identified which permit detection of fungal infection on the surface of corn kernels by photoacoustic infrared spectroscopy. In a blind study, ten corn kernels showing bright greenish yellow fluorescence (BGYF) in the germ or endosperm and ten BGYF-negative kernels were correctly classified as infected or not infected by Fourier transform infrared photoacoustic spectroscopy. Earlier studies have shown that BGYF-positive kernels contain the bulk of the aflatoxin contaminating grain at harvest. Ten major spectral features, identified by visual inspection of the photoacoustic spectra of A. flavus mycelium grown in culture versus uninfected corn, were interpreted and assigned by theoretical comparisons of the relative chemical compositions of fungi and corn. The spectral features can be built into either empirical or knowledge-based computer models (expert systems) for automatic infrared detection and segregation of grains or kernels containing aflatoxin from the food and feed supply.
黄曲霉和其他致病真菌呈现出典型的红外光谱，与玉米等底物材料的光谱有显著差异。在此基础上，已识别出特定的光谱特征，可通过光声红外光谱法检测玉米粒表面的真菌感染。在一项盲测中，通过傅里叶变换红外光声光谱法，正确区分了十颗在胚芽或胚乳中呈现亮黄绿色荧光（BGYF）的玉米粒和十颗BGYF阴性的玉米粒是否受到感染。早期研究表明，BGYF阳性的玉米粒含有收获时污染谷物的大部分黄曲霉毒素。通过目视检查培养的黄曲霉菌丝体与未感染玉米的光声光谱，识别出十个主要光谱特征，并通过对真菌和玉米相对化学成分的理论比较进行了解释和归属。这些光谱特征可纳入经验性或基于知识的计算机模型（专家系统），用于自动红外检测以及从食品和饲料供应中分离出含有黄曲霉毒素的谷物或玉米粒。
