Andhra Pradesh Health Minister Satya Kumar Yadav said on Monday that the Tirumala temple complex is set to deploy advanced electronic nose (e-nose) and electronic tongue (e-tongue) machines to monitor the quality of prasadam and food served to devotees.
According to a report by NDTV, the devices will be part of a ₹25-crore food testing laboratory being set up at Tirumala to examine ingredients such as ghee, dry fruits and spices used in offerings.
The facility is meant to strengthen food safety checks and restore confidence after concerns around adulterated ghee used in prasadam preparation, NDTV cited officials as saying.
Here's explaining what exactly these e-nose and e-tongue machines are and how they work.
What are e-nose and e-tongue?
An e-nose is a sensor-based device designed to detect odours and volatile compounds released from food. Research published in the journal Biosensors explains that, rather than identifying a single chemical like conventional laboratory tests, an e-nose analyses the overall pattern of gases emitted by a sample. These patterns act as an “odour fingerprint” matched against known quality profiles.
An electronic tongue (e-tongue) applies a similar concept to liquids, focusing on taste-related chemical components. It uses multiple electrochemical sensors that respond to dissolved substances responsible for sweet, salty, sour and bitter characteristics.
How do they work?
E-nose system uses an array of gas sensors that respond differently to volatile organic compounds. The resulting electrical signals are processed using pattern-recognition software and statistical models to determine freshness, spoilage or adulteration. Widely used across dairy, edible oils and processed foods, e-nose helps detect fermentation changes and contamination by analysing volatile chemical signatures.
E-tongue, meanwhile, evaluates complex mixtures through overall response patterns instead of measuring one compound at a time. Electrical signals generated by sensor interactions are analysed using pattern-recognition models and compared with reference data. These systems are commonly used to assess oils, beverages and dairy products for consistency, quality control and adulteration detection.
Why both devices are used together
Research on multisensor food-analysis systems shows that combining smell- and taste-based sensors provides a more complete assessment of quality than either device alone.
- E-nose: Detects volatile compounds linked to aroma, spoilage or contamination.
- E-tongue: Detects dissolved chemicals that influence taste and composition.
Together, they can identify adulteration, freshness changes and flavour inconsistencies more quickly than traditional laboratory testing methods.
Studies on food-quality monitoring technologies also note that such systems offer rapid, repeatable and non-destructive testing, making them useful for routine screening in production environments.
How data is interpreted
Both devices rely heavily on computational analysis.
Sensor signals are processed using statistical tools and machine-learning models that classify samples into categories such as acceptable, spoiled or adulterated. The Biosensors study highlighted that advances in artificial intelligence (AI) are improving accuracy and enabling systems to learn from new samples over time.
Why such technology is used in food testing
Traditional food testing often requires laboratory procedures, trained personnel and time-consuming analysis. In the case of Tirumala, it can also complicate religious protocols in cases such as temple prasadam, which should not be consumed or handled in ways that violate ritual practices before offering.
Electronic-nose and electronic-tongue systems allow rapid and automated quality checks without requiring human tasting or smelling. Research and industry documentation show that they are already used globally in sectors such as dairy, edible oils, beverages and processed foods to detect spoilage, contamination and flavour variation.
Why is Tirumala deploying e-nose and e-tongue systems?
A controversy erupted in 2024 when Andhra Pradesh Chief Minister Chandrababu Naidu alleged that adulterated ghee had been used to prepare Tirumala laddus under the previous Jagan Mohan Reddy-led government. A Special Investigation Team (SIT) later confirmed adulteration in the supplied ghee.
According to the SIT report, the adulterated ghee supplied to TTD was made by mixing palm oil and palm kernel oil along with additives such as beta-carotene, acetic acid ester and artificial ghee flavour.
Following the episode, the state government approved a modern food testing facility in Tirumala to tighten monitoring of raw materials and finished prasadam. The new lab, backed by the Food Safety and Standards Authority of India (FSSAI), will deploy sensing technologies such as e-nose and e-tongue for routine checks.
What this means for Tirumala temple
If deployed in routine checks, such systems could help monitor raw materials and finished prasadam for consistency and purity by flagging unusual chemical patterns.
The technology does not replace full laboratory testing but can function as an early screening tool, allowing quicker detection of anomalies in taste, smell or composition.
 "What are 'e-nose' and 'e-tongue' techs being deployed at Tirumala temple?")
