Food Fraud: Focus on Tea

Adulteration

Tea is widely recognized as one of the most popular beverages in the world, and its authenticity depends on numerous factors related to the chemical composition of the final product. Global climate change will have a significant impact on tea cultivation, its final quality, and, ultimately, tea prices. Rising temperatures and extreme weather events pose a serious threat to the resilience of tea production systems. Consequently, there is an increased risk of high-quality teas being adulterated by blending them with cheaper varieties. In fact, the most frequently encountered authenticity issues include the mislabeling of tea quality and geographical origin.

Genetic Analysis

The analytical method underpinning genetic analysis is the DNA amplification technique known as “Polymerase Chain Reaction” (PCR). Specifically, the “DNA fingerprinting” method exploits existing variations (polymorphisms) within the genetic code of species or varieties. This allows for the precise and reproducible identification of not only the genus and species but also the specific variety of a batch of medicinal plants, whether fresh or processed. Furthermore, the use of DNA-based technologies makes it possible to determine the purity of a raw material batch and identify the potential presence of adulterating species—referring to the deliberate and intentional addition of different botanical species, sometimes belonging to the same genus. DNA testing, using specific methodologies in combination with chemical and morphological analyses, represents a valuable tool for demonstrating the quality of plant raw materials and their derived products.

Botanical Identification

Botanical recognition analysis of a plant has application limits, especially when considering finely ground, powdered, or micronized raw materials. In such cases, even microscopic analysis does not allow for species identification or the detection of adulterants and contaminants. Furthermore, botanical analysis alone cannot correctly distinguish between varieties of the same species or determine their geographical origin. In recent years, the limitations of botanical plant identification have been overcome through genetic analysis, the same technology used in the forensic sector. DNA fingerprinting analysis enables the unique and reproducible identification of the genus, species, and variety of the raw material, even when it has been processed (e.g., dried, crushed, powdered, freeze-dried, pressed, etc.) and, in some cases, even within semi-finished or finished products.

Assessments

Similarly, detecting adulteration and identifying the botanical species present in herbal blends is essential to ensure safety and the benefits expected by consumers. A comprehensive and accurate assessment for plant identification requires a combination of physicochemical tests along with macroscopic and microscopic analysis of the plants’ morphological characteristics.