Limit of Detection for Five Common Adulterants in Milk: A Study With Different Fat Percent

Milk adulteration is one of the most dishonest food preparation, which not only reduces the nutritional value but also causes various diseases to human. Some of the common adulterants are detergents, ammonium sulphate [(NH
₄
)
₂
SO
₄
], sodium hydroxide (NaOH), sodium-bi-carbonate (NaHCO
₃
), and common salt (NaCl). The aim of this paper is to identify the minimum detectable limit for the above five adulterants in milk. An impedance sensor is used, which is sensitive to the ionic concentration of the measuring medium and gives different phase angle of the impedance, when immersed in different adulterated/unadulterated milk. Signal transduction circuit is designed to convert the phase angle to voltage and for display in liquid crystal display. By this detection system, the limit of detection of adulterants in milk with different fat % (from 1.5% to 20%) is studied. Commercial packet milk, ultra high temperature milk, and raw-milk (directly collected from the milk collection center) are used for the experiment. Experimental results are plotted in origin software and statistical analysis method analysis of variance is applied on experimental data for verification of the result and to check the data consistency.