The Analytical Laboratory of the Sri Lanka Tea Board (SLTB) is the national testing facility for safeguarding the quality and safety of Ceylon Tea in domestic and export markets. It undertakes chemical, microbiological, and pesticide residue analysis of made tea against parameters specified by national and international regulatory bodies, including pesticide maximum residue limits (MRLs). The laboratory holds ISO/IEC 17025:2017 accreditation from the Sri Lanka Accreditation Board for Conformity Assessment (SLAB) and applies internationally recognized test methods, as included in its accredited scope. The laboratory is equipped with state-of-the-art instrumentation, including LC-MS/MS, GC-MS/MS, and HPLC, and functions as Sri Lanka’s principal technical authority for tea quality assessment in the international tea trade.
Structure of the Laboratory
The Analytical Laboratory consists of the following units:
- Chemical Analysis Unit
- Microbiological Analysis Unit
- Pesticide Residue Analysis Unit
- Quality Assurance Unit
Chemical Analysis Unit
The Chemical Analysis Unit conducts testing of a wide range of chemical composition and quality parameters in tea using internationally recognized standard methods, including ISO methods, as well as validated in-house methods, as appropriate to the respective analytical parameter.
The Unit employs a range of analytical techniques, including gravimetric, titrimetric, spectrometric, and chromatographic techniques such as High-Performance Liquid Chromatography (HPLC) and HPLC with Evaporative Light Scattering Detection (HPLC-ELSD), to generate accurate and reliable analytical results. These include:
- Moisture Content (Loss in Mass) — Test Method: ISO 1573:1980
- Total Ash — Test Method: ISO 1575:1987
- Water-Soluble Ash — Test Method: ISO 1576:1988
- Alkalinity of Water-Soluble Ash — Test Method: ISO 1578:1975
- Acid-Insoluble Ash — Test Method: ISO 1577:1987
- Crude Fibre — Test Method: ISO 15598:1999
- Water Extract — Test Method: ISO 9768:1994
- Total Polyphenols — Test Method: ISO 14502-1:2005
- Theanine — Test Method ISO 19563:2017
- Caffeine — Test Method: ISO 14502-2:2005
- Determination of Basic Radiation
- Sieve Analysis / Tea Dust Analysis
Microbiological Analysis Unit
Conducts microbiological testing using standard culture-based and rapid detection methods, including Total Plate Count, Yeast and Mould Count, Coliform testing, and detection of Escherichia coli, ensuring the supply of safe, high-quality tea to local and international markets:
- Total Plate Count — Test Method: ISO 4833-1:2013
- Yeast and Mould Count — Test Method: ISO 21527-2:2008
- Coliform Test for Tea — Test Method: ISO 4831:2006
- Escherichia coli Test for Tea — Test Method: ISO 7251:2005
- Microscopical Examination
- Dead Insects and Fragments:
- Alive Insects and Fragments:
- Foreign Matter
- Visible Mould Growth
- Particle Appearance
Pesticide Residue Analysis Unit
Using advanced chromatographic and mass-spectrometric techniques, performs pesticide residue analysis to verify compliance with international food safety regulations and maximum residue limits (MRLs) set by markets.
- Diuron & Hexaconazole Analysis — Test Method: QuEChERS – LC-MS/MS
- MCPA & 2,4-D Analysis — Test Method: LC-MS/MS
- Imported Tea Analysis — Test Method: QuEChERS – LC-MS/MS
- Glyphosate Analysis — Test Method: LC-MS/MS
Quality Assurance Unit
Maintains the laboratory’s accreditation standards and overall quality management system. This includes overseeing compliance with ISO/IEC 17025:2017, coordinating inter-laboratory proficiency testing to benchmark and improve performance, managing internal audits and document control, and maintaining the quality management system documentation underpinning the laboratory’s operational consistency.
Functions of the Laboratory
Analytical Services for Stakeholders
The laboratory offers testing services to tea producers, exporters, and industry stakeholders, including chemical composition analysis, polyphenol and antioxidant profiling, microbiological testing for contaminant detection, and pesticide residue analysis to confirm compliance with international standards. It issues internationally recognized test reports and certificates of analysis required for export documentation, providing stakeholders and trading partners with the scientific assurance needed to compete with confidence in global markets.
Regulatory Support
The laboratory supports Sri Lanka’s tea industry by ensuring adherence to national and international food safety requirements. It conducts analyses for pesticide residues and other contaminants to safeguard consumer safety, assists the Tea Commissioner’s Division in regulatory enforcement and evidence-based decision-making through timely and reliable testing services, and verifies that black tea and green tea comply with ISO 3720 and ISO 11287 respectively, as well as SLTB’s Minimum Quality Requirements.
Research and Development Support
The laboratory collaborates with the Sri Lanka Tea Research Institute to develop new analytical methodologies and integrate them into routine testing operations. It participates in ISO working groups for standards and test method development, contributes to ISO-organized inter-laboratory comparison studies for the validation of new test methods, and supports university researchers to conduct their tea related research projects.
Technical Training support
The laboratory offers structured industrial training programmes for undergraduates, providing hands-on exposure to advanced laboratory practices and building technical expertise for the industry.
Through its testing protocols, adherence to international standards, and ongoing method development, the SLTB Analytical Laboratory remains a key technical resource supporting the quality and reputation of Ceylon Tea in global markets.
