Spectrometric Milk Analyzer

Abstract

Food spoilage and adulteration are issues of great concern, not only for the food industry, but also for consumers. Analytical techniques for food analyses are usually time-consuming, require sample pre-treatment and employ high-quality devices. This paper details a low-cost application for the examination of pasteurized milk. The samples were analysed using a 6-channel visible sensor which acquires spectral data from 430 nm to 670 nm. It has a low power consumption and can be easily interfaced with other devices that use serial communication. The spectrometric setup was encapsulated within an opaque container to prevent any external light to reach the surface of the sensor. The analysed samples were placed between the light source and the visible sensor to detect any intensity changes caused by milk degradation in time. To prevent any displacements between the systems components, a 3D-printed holder was designed and printed to support the sensor, the light source and the cuvette with the sample. The purpose of this work is to investigate if visible spectroscopy can be used to validate milk freshness. The sensor acquired data for several days. The results show a change in the spectral data read by the sensor which correspond with the moment the analysed milk turned sour. This sourness of the milk is the results of the fermentation process which causes lactose to turn into lactic acid.