Food-grade phosphoric acid: the documentation checklist buyers should ask for

Food-grade phosphoric acid is a commodity acid with an uncommon documentation burden. The specification is well known — FCC or equivalent, with tight limits on heavy metals — but a purchase order for a beverage or dairy plant is not satisfied by a grade claim alone. The buyer needs to know which lot was tested, how it was packed, where it was stored and what happened between the source plant and the receiving bay.

FCC grade is a specification, not a document set

FCC, USP and food-chemical grades define limits and test methods. They do not, by themselves, produce a lot record. A COA can cite the grade while omitting the lot-specific heavy-metal result, or report a result without the method. Both are gaps. The grade claim tells you what the supplier intends to meet; the lot data tells you what the batch actually did.

The COA should match the lot, not a catalogue

For food-grade phosphoric acid, the critical lines are assay, fluoride, chloride, sulphate, iron and heavy metals — particularly lead and arsenic, depending on the grade. The exact limits come from the specification the buyer has accepted. The method matters: a colorimetric screen is not the same as ICP-MS, and a result below a limit is only meaningful if the detection capability is adequate. Ask for the method alongside the number.

The COA should also show the pack size and the lot number actually delivered. A certificate for a 35 kg carboy does not cover a 1,200 kg IBC unless the traceability record links the two to the same source batch and repack operation.

Traceability from source to pack

Traceability is a chain, not a document. The source plant’s batch number should link to the receiving record at the terminal, the repacking record, the pack label and the dispatch invoice. If the acid is repacked into carboys, the repack lot needs its own identity and its own retained sample. Without that link, a recall or a customer complaint can only be answered at the level of “a drum from that shipment” — which is not an answer.

Packaging integrity and food-contact controls

• The carboy or drum should be new or dedicated to food-grade use, with a clean liner and a sealed closure. A reconditioned container needs a documented food-contact cleaning history.
• The closure should be tamper-evident where the application requires it, and the pack should arrive with an intact seal.
• Labels should identify the product, grade, lot, net weight, hazard marks and the food-grade status without ambiguity.
• Storage should be segregated from technical-grade acids, with no shared decanting equipment or drip trays.
• Any repacking should be covered by a cleaning log, a line-clearance record and a deviation process.

Questions for the supplier qualification file

1. 01 Which specification and grade does the lot meet, and can you share the lot-specific COA with methods?
2. 02 What is the heavy-metal profile, including lead and arsenic, and which method was used?
3. 03 How is the food-grade material segregated from technical-grade acid in storage and repacking?
4. 04 What is the traceability chain from source batch to the delivered pack, and how long are records retained?
5. 05 What food-grade declaration and regulatory registrations apply to the site and the activity?
6. 06 What is the pack construction, closure and cleaning history?
7. 07 What is the deviation and recall procedure if a lot is found non-conforming after dispatch?

Food-grade documentation is not paperwork for its own sake. It is the evidence that the acid in the carboy is the acid that was tested, packed and released. Build the qualification file around that chain and the audit becomes a review, not a reconstruction.