Abstract
We developed a prototype of an oil identification sensor to realize food safety and measures of that
purpose. We analyzed the absorption spectrum of six edible oils and one inedible oil and determined
five infra-red wavelengths for identifying them. We used 1657, 1685, 1713, 1727, and 1750 nm and five
laser diodes (LD) of each wavelength for our prototype sensor. The small, 36 (width) × 80 (length) × 46
mm (height) prototype sensor had a pair of a projector (five LDs) and a receiver (one photo-diode) to
slot it into a factory sensor system. The identification time for one oil sample was 250 microseconds.
Such capability is adequate to be adapted into a factory checking line. The oils were clearly
distinguished at different positions in a two-dimension map with normalized absorbance ratio at 1727 nm
to at 1713 nm vs. absorption difference at 1727 nm and at 1713 nm.
