Spoilage of bulk-stored grain leads to decreased nutritional value and poses health hazards due to the formation of irritating volatile metabolites inside grain bins. Co-occurrence of insect species and molds are common in a stored-grain ecosystem and are the causes of spoilage. In this study, new chemical signatures and volatile compounds evolving from grain having a combination of molds and insects were identified. The results of this research provided confident information for the development of odor sensor arrays for grain quality monitoring. In this project, Gas Chromatography and Mass Spectrometric (GC-MS) analysis of the gas samples trapped in dimethylpoly-siloxane was performed. The analytical data from the GC-MS spectra were validated, interpreted and compared using the NIST/NIH (National Institute of Standards and Technology and National Institute of Health, USA) Mass Spectral Library.