Mid infrared (MIR) spectroscopy theoretically has advantages with respect to spectral information in comparison with near-infrared spectroscopy, though it has been very difficult to obtain the useful spectrum from wet materials such as foods because of the strong absorption of MIR radiation by water. In parallel with the development of Fourier transform infrared (FT-IR) technology, various sampling techniques, for example; attenuated total reflection (ATR), diffuse reflection, and photoacoustic methods, have evolved, and provide FT-IR spectroscopy with substantial potential as a qualitative and quantitative analytical tool for food processing. In this review, recent developments in mid-infrared spectroscopy, particularly FT-IR/ATR methods, have been taken an overview of sugars focusing on its applications to qualitative and quantitative analysis of foods and agricultural products. In addition, this paper reviews the applications of FT-IR/ATR methods to monitoring metabolisms of cultivation processes and these studies represented an important step in the development of nonintensive on-line monitoring devices for food processing and bioprocesses. Furthermore, we survey the importance of infrared spectroscopic characteristics of foods in order to evaluate the effects of application of infrared irradiation to thermal operations in food process such as heating and drying.