Botanical and Pharmacognostical Methods for Detection of Adulteration in Commercial Spices and Plant-Based Foodstuffs

Food adulteration is a critical global public health concern that compromises nutritional quality and poses serious health hazards. Plant-based food products, particularly high-value spices, culinary herbs, and herbal powders, are frequently targeted for intentional economic adulteration using toxic dyes, inferior plant species, and inert starches. Traditional chemical detection techniques often fail to distinguish closely related plant species or organic plant substitutes. This study demonstrates the efficacy of botanical validation approaches combining anatomical microscopy, micro-chemical localization, and thin-layer chromatography (TLC) to detect common adulterants in commercial black pepper (Piper nigrum), turmeric (Curcuma longa), and chilli powder (Capsicum annuum). Anatomical screening revealed the presence of papaya seeds (Carica papaya) in black pepper samples through distinct sclereid ring structures and endocarp morphology. Metanil yellow and lead chromate contamination in market turmeric samples were identified via pH-dependent colorimetric reactions and micro-chemical staining. Furthermore, starch adulteration from wild roots was detected using iodinestaining microscopy under polarized light. Out of 50 commercial spice samples collected from local markets, 32% exhibited botanical or chemical adulteration. These findings underscore the importance of integrating botanical microscopy and simple qualitative chemical markers into routine quality control frameworks for ensuring safe and authentic food for consumers.