Non-invasive milk quality estimator based on capacitive changes in milk with customized Electrode Receptacle

Milk is considered to be a complete food that provides all necessary nutrients to the human body. It is thus very important to ensure good quality milk is consumed. However, the quality of commercially available milk is inconsistent across various sources. A study conducted by the Food Safety and Standards Authority of India (FSSAI) in 2018 found that 68.7 % of milk and milk by-products produced in the country were found to be laced with polluting ingredients. Tasting the milk to ascertain its quality is not always feasible. Developing a device or a non-invasive method to quantitatively ascertain the quality of milk is the need of the hour. We have attempted to develop a system and an inexpensive device capable of detecting the quality of milk without opening the packaging. The experimental setup consists of a circuit and an electrode receptacle which is customized according to the targeted milk packaging. There has been a lot of research in this domain but correlating the capacitance directly to the quality of milk has not been attempted before. In this method, the dielectric constant of the milk is determined from the capacitance read from the experimental setup which is then correlated to the pH of the milk. pH is universally considered to be an indicator of milk quality with the pH of fresh milk being around 6.5-6.7. A regression based model is developed using the data capturing the change in capacitance and pH values over time to estimate the quality of milk. The deployment of this system in the Indian market will help in dynamic pricing based on a quantitative freshness measure and assure the customer of milk quality. The results of the research and a prototype of the device are presented in the paper.