Now, an e-nose to sniff out pesticides in tea

With a crop of about 1,200 million kgs, India is the world’s largest black tea producer

The e-nose uses a multiplate reader-based system.

The Tea Research Association (TRA) has developed an ‘e-nose,’ a bio-sensing system for detection of pesticides in tea.

The project, implemented by the C-DAC (Centre for Development of Advanced Computing), Kolkata, has reached the prototype stage.

Field trials

“We now need field-trials before this system can be taken up for developing a commercially viable bio-sensing system,” according to Joydip Phukhan, TRA.

Mr. Phukhan said the machine needs to be simple-to-use with need for minimal maintenance as tea gardens are mostly located in remote areas ‘where servicing may become an issue.’

The methodology involves testing the tea leaves after cutting them into small pieces, washing them and then taking them through a chemical process. The tea leaves with presence of pesticides change colour. The ‘e-nose’ then measures the extent of the pesticide residue through a ‘multiplate reader-based system.’

“The proposed ‘proof-of-concept’ (PoC) study on pesticide detection in tea by the bio sensing system has been successfully completed by following two scientific approaches,” concluded a C DAC paper, which was given to the Union Commerce Secretary during her recent visit.

According to the paper, following successful completion of PoC study, it has been well established that the pesticide issue can be addressed through indigenously developed technology. It is being termed as an e-nose which will “sniff” out pesticide residues in tea.

TRA and Birla Institute of Technology and Science (BITS), Goa Campus were the collaborating agencies for this project while C-DAC was the implementing agency. BITS was entrusted with the development of enzyme-based colorimetric biosensor and enzyme biosensor while C-DAC developed the colour sensor with compatible algorithms and software. The Tea Board-funded project is worth Rs.40 lakh.

Imported kit

Alongside, the TRA is also trying to check the efficacy of an imported pesticide testing kit which is used on tea leaves washed in distilled water.

Ideally, to keep pesticide residues within permissible limits, it is essential that a six-day gap is given between the use of the chemicals and the plucking.

Problem arises when this is violated as then the chemical traces pass onto the crop.