Utilization of gold nanoparticles to detect formalin adulteration in milk

Despite the addition of formalin in milk or any food product is banned in most of the countries, its use continues because of capability to increase shelf life of food by several folds and cheap availability. An addition of small quantity of solution of gold nanoparticles enhanced the capability of Tollen's reagent and produced visible change in color due to presence of trace amount of formalin in solution. In order to establish this new technique, various samples of milk with different quantities of formalin were prepared and color change after the reaction with gold nanoparticles suspended in Tollen's reagent was visibly observed. This was also monitored by UV-Visible Spectrophotometry to confirm the formation of gold core silver shell particles. This paper presents an easy, cost effective way to detect formalin adulteration in milk at very low concentrations and could be adopted in the area of quality control and can be further modified for use in the testing of other food products. (C) 2021 Elsevier Ltd. All rights reserved.