Tea Standards and Test Methods: The ISO Series, Residue Testing and the COA

A tea specification stands on four kinds of reference: the standard that defines the product, the standard that fixes the method, the legal limit of the destination and the report that shows the lot against both. This page lists the ISO standards for tea, says what each controls and links to the pages that explain the tests and the limits. Checked 19 October 2026.

The ISO series for tea

Standard	Subject	Edition seen	Use in a green tea spec	Page
ISO 11287	Green tea, definition and basic requirements	2011	Identity of the product	ISO 11287 for green tea
ISO 3720	Black tea, definition and basic requirements	2011	Not for green tea	Particle size page
ISO 1839	Sampling of tea	1980	How the sample is drawn	Sampling to ISO 1839, pre-shipment samples
ISO 11286	Classification of grades by particle size analysis	2004	Size method for the grades it fits	ISO 11286
ISO 1573	Loss in mass at 103 °C (moisture)	1980	Moisture line	Moisture and shelf life
ISO 1575 and ISO 1577	Total ash and acid-insoluble ash	1987	Mineral and soil content lines	Certificate of analysis
ISO 9768	Water extract	1994	Soluble content line	Certificate of analysis
ISO 14502-1 and -2	Total polyphenols and catechins	2005	Only if the buyer asks	Certificate of analysis
ISO 3103	Preparing tea liquor for sensory tests	See the article	Cupping	Tea cupping

Catalogue listings show these as published and confirmed. They are copyright texts and we did not read them. Cite the number with its year, and name the method in the spec so the lab and the buyer measure the same thing.

Legal limits for tea leaf in the EU

Subject	Limit seen	Where it comes from	Page
Pesticide residues	Specific MRL per pesticide, otherwise 0.01 mg/kg	Regulation (EC) No 396/2005	EU MRL lookup
Pyrrolizidine alkaloids, dried tea	150 µg/kg for the listed sum	Regulation (EU) 2023/915	Pyrrolizidine alkaloids
Perchlorate, dried tea	0.75 mg/kg	Regulation (EU) 2023/915	Anthraquinone and chlorate
Anthraquinone	See the article	Pesticide MRL rules	Anthraquinone and chlorate
Heavy metals	See the article	Contaminants rules	Heavy metals

For powdered tea extracts the contaminants regulation applies a concentration factor of 4 to the listed tea values. The figures are the ones published in the regulation at the time of writing. Check the consolidated text and the database before you contract.

Chinese type standards and microbiology

Subject	What it covers	Page
GB/T 14456	Chinese national green tea series: gunpowder, mee, steamed, large leaf and medium or small leaf	GB/T 14456 green tea types
Microbiological limits	Total count, yeast and mold, E. coli and Salmonella: buyer-set lines and the ISO methods behind them	Tea microbiology limits
Foreign matter	Extraneous and foreign matter, metal and iron filings: tray test, magnet test and how to write the limit	Tea foreign matter test

How the pieces fit

Question	Answer	Page
What is the product	The defining standard, plus buyer lines	ISO 11287
How was it sampled	ISO 1839 and the inspector’s record	Sampling to ISO 1839, sample guide
How was it tested for residues	A panel with a quantification limit at or below the limit	Test panel
What does the report say	A COA with methods and the lot link	COA
Which papers sit around it	Certificates and market rules	Certificates hub

Writing a standard into a spec

Part	Write
Product	“Green tea to ISO 11287:2011”
Method per line	The standard number with its year
Sampling	ISO 1839 or the pre-shipment procedure, drawn by the buyer’s inspector
Limit source	The regulation and the date of the lookup
Report	A COA per lot from an accredited lab with LOQ per analyte

The full spec template is in the green tea specification guide.

Common mistakes when citing a standard

Mistake	Why it matters	Fix
Number without a year	A later edition changes what the number means	Write “ISO 11287:2011”
Citing a standard that is not for the product	ISO 3720 is for black tea	Check the title and scope before it goes in a green tea contract
Copying a limit from a summary	Summaries, including ours, can lag the text	Buy the text or ask the lab to confirm
Treating an ISO method as a legal limit	ISO fixes how to measure, not what is allowed	Name the regulation for the limit and the ISO method for the test
No sampling line	Results cannot be tied to the lot	Cite ISO 1839 or the pre-shipment procedure: see sampling to ISO 1839

A note on this site. greenteavietnam.com is a matching service. We do not test tea, sell standards or issue certificates. Standards are the property of ISO and the national bodies. If you want matched Vietnamese suppliers who can work to your standards, name them in the RFQ form. We reply within 24 business hours.

Frequently asked questions

Sources

• Genorma: ISO 3720:2011 Black tea, definition and basic requirements
• Genorma: ISO 1839:1980 Tea, sampling
• Genorma: ISO 11286:2004 Tea, classification of grades by particle size analysis
• EUR-Lex: Regulation (EU) 2023/915 on maximum levels for certain contaminants in food (pyrrolizidine alkaloids and perchlorate in tea)
• EUR-Lex: Regulation (EC) No 396/2005 on maximum residue levels of pesticides

Standards and rules are cited as references. They are not claims about greenteavietnam.com or any supplier. Confirm the edition and current status with the issuing body.