Globally growing demands of food supply chain has heightened concerns regarding food safety where rising instances of food adulteration has created an urgent need for rapid, cost-effective, and accurate sensing technologies. In recent years nano colorimetric and plasmonic based sensing techniques have been studied extensively as innovative approach for the detection of food adulterants. In particular, colorimetric sensors driven by nanoscale mechanisms, inducing alteration in optical characteristics of the material, have the ability to detect a variety of adulterants. Similarly, plasmonic sensors identifies the same range of contaminants by leveraging surface plasmon resonance for enhanced sensitivity. Here in this chapter, an overview into the principles behind nano colorimetric and plasmonic phenomena have been described highlighting several probes designed for adulterant detection. In addition, the chapter also explores the current challenges in the field and compares the present technique with existing sensing protocols. Lastly, the chapter concludes with a discussion on future perspectives and emerging trends summarizing a comprehensive review on the potential of such methods towards the advancement of food safety monitoring.