Metals in Food: Features, Innovations, and Challenges of Newly Designed Colorimetric Probes

Metals in food originate from both natural and human sources. In living organisms, they are classified as essential or non-essential. Essential metals are vital for biological processes, whereas non-essential metals are typically harmful. This article offers a thorough overview of the physiological roles, sources, and legal regulations concerning metals in food. It explores innovative colorimetric sensing elements in which color changes indicate shifts in absorption and/or emission spectra within the visible range. A detailed review of advanced sensing components, such as macrostructures, nanostructures, biomolecules, and polyphasic systems, is included. Additionally, it covers the latest monitoring techniques and novel readout methods. The article highlights new A. I.-driven systems, mobile diagnostics, and CSA that enable rapid, sensitive, and intelligent detection. Integrating recently developed colorimetric probes with advanced readout technologies for visual detection improves selectivity and sensitivity, effectively addressing challenges posed by complex food matrices. In the last part, the article summarises key research with practical applications in modern colourimetric food analysis. In short, the review highlights the combined effectiveness of newly developed, highly selective and sensitive sensor components, advanced support materials, and innovative visual signal-processing systems. It describes how this modern visual platform enhances the essential analytical sector of metals in food.