Simultaneous detection of Aspergillus moulds and aflatoxin B1 contamination in rice by laser induced fluorescence spectroscopy

Mould and aflatoxin contamination remains a serious threat to food quality and safety. In this study, simultaneous detection of Aspergillus moulds and aflatoxin B1 (AFB1) contamination in rice was investigated by laser induced fluorescence (LIF) technology for the first time. Different Aspergillus strains belong to toxigenic and non-toxigenic species were artificially inoculated in rice samples and storage for a period of time to evolve into various mould and AFB1 infection levels. Spectral analysis and principal component analysis (PCA) indicated that mould activity could be monitored by LIF spectroscopy. Subsequently, three classification methods based on linear and non-linear algorithms were established to classify rice samples in terms of the type of infected mould, mould infection level as well as AFB1 concentration. The best correct classified rate obtained achieved 97% with false positive rates less than 2%. In addition, the discrimination towards rice flour samples performed better than kernel samples. These findings verify the potential of LIF spectroscopy as a rapid and non-destructive way for sensitive and effective detection of mould and aflatoxin contamination in grains without any complicated pre-processing.