Supplement factory QC labs: what Thai law actually requires you to test

Supplement factories hear this question constantly: which notification do we test against? The wrong but widespread answer is MOPH No. 416, whose Clause 4 states outright that it does not apply to health supplement products or food additives (we covered 416 itself in the food pathogen-testing guide). The real criteria live in Notification of the Ministry of Public Health No. 293 (B.E. 2548), gazetted 28 December 2005, plus the duties GMP 420 attaches to every food factory.

Clause 5 of No. 293: five requirements

1. The product has the specific characteristics of its kind
2. Pathogenic bacteria within limits the FDA prescribes with Food Committee approval. The numbers sit in an FDA-level announcement, not in 293 itself. We could not find a current, verifiable copy published online; request it from the FDA or your contract lab directly rather than copying figures from a blog
3. Escherichia coli detected at less than 3 per 1 g by the Most Probable Number method. This is the one criterion where the notification itself prints both the number and the method
4. Microbial toxins, pesticide residues, contaminants and veterinary drug residues per the notifications specific to each
5. For vitamin or mineral products, content between 15% of the Thai RDI and the prescribed maximum. That is assay work, not microbiology, and nearly every factory already outsources it

What GMP 420 adds

Clause 7 of No. 293 binds producers to the production-process notification, which today is GMP 420, and four of its clauses land directly on the lab: finished-product analysis at least once a year by a government or accredited laboratory (3.9.1), balances and measuring equipment calibrated with appropriate frequency and at least once a year (2.8), records kept at least one year past the date on the label (3.12), and an internal quality audit once a year (3.13). Two common misreadings: clause 2.8 does not require an ISO/IEC 17025 calibration lab, and the word HACCP appears nowhere in the notification. Customers may demand both in contracts, but that is commerce, not law.

At the bench: what stays in-house

Our position: most supplement factories should not buy into a full in-house pathogen panel. The annual sample volume never justifies the expired media you will throw away or the method QC burden. Send the yearly panel to an accredited lab per 3.9.1 and keep the frequent work at home: E. coli and coliforms by the three-tube MPN of BAM Chapter 4, with LST broth as the presumptive tube, BGLB confirming coliforms and EC broth or EC-MUG confirming E. coli. The shelf needs test tubes with Durham tubes, three media, an incubator and pipettes, plus swabs for line hygiene monitoring. That genuinely covers the day-to-day.

Facts checked against the texts of No. 293, GMP 420 and BAM Chapter 4 on 24 August 2026, with one exception stated above: the FDA announcement carrying the Clause 5(2) pathogen limits, which we could not verify online. If you hold the real text, check it against this article before relying on either.