The regulations, and the shape of their silence

Seaweed has no species-specific federal food safety regulation. In practice, a facility that washes, dries, cuts, toasts, blanches, or packages seaweed is a food facility and lands under Part 117 unless it qualifies as a farm or a qualified exempt operation.

The farm/facility line is where most California operators get stuck. Harvesting and washing on the boat or beach can read as farming; drying and packaging for sale usually reads as manufacturing/processing — which triggers facility registration and a full food safety plan.

Part 117 requires a preventive controls qualified individual (PCQI) to prepare or oversee the plan. There is no seaweed-specific PCQI curriculum, so operators are trained on produce or general food examples that don't cover iodine, arsenic, or biotoxin uptake.

Some states — Connecticut, Maine, Alaska among them — direct seaweed operators to seafood HACCP and require standardized seafood HACCP training. Others treat seaweed as a general food under Part 117. Both cannot be right nationally, and the difference changes required training, records, and inspection authority.

FDA's Fish and Fishery Products Hazards and Controls Guidance (4th ed.) — the operational manual behind Part 123 — has no seaweed chapter. States that route seaweed here are extending shellfish and finfish chapters by analogy.

The practical consequence: two California operators doing identical work can be told to build two different plans, and a buyer in another state may reject a plan built to the wrong framework.

The National Sea Grant Law Center's 2024 advisory to the Seaweed Food Safety Working Group documents exactly this: growers are drying and dehydrating seaweed and receiving different regulatory answers from different states.

The stakes are concrete. 'Processed food' triggers facility registration, a written plan, process validation for the drying step, and in some states a cannery or processed food registration. 'Raw agricultural commodity' does not.

Drying is also the step with the least validation data. Time, temperature, airflow, and water activity endpoints for safe seaweed drying are not standardized anywhere in federal guidance.

The National Shellfish Sanitation Program gives shellfish a workable structure: states classify growing waters, run monitoring, and other states accept the resulting certification so product can move interstate.

Seaweed has no classified-waters framework, no interstate certification, and no model ordinance. Water quality expectations for seaweed harvest and grow-out are set operator by operator, often by borrowing shellfish closure data — which is a reasonable proxy, not a legal standard.

This is the most commonly proposed structural fix: either extend NSSP-style growing-water classification to seaweed, or create a parallel model ordinance for it.

Seaweed concentrates trace elements — that is part of its nutritional value and its hazard profile. Inorganic arsenic in some brown algae and iodine in kelps are the two most consequential.

Without federal action levels, testing thresholds are set by buyer contracts, foreign standards (EU, France, Japan, Australia/New Zealand), or nothing. Two labs can report the same sample as pass and fail against different reference limits.

Species-specific and part-specific variation is large enough that a single blanket number would be poor policy — but the absence of any number is worse, because it removes the operator's ability to demonstrate compliance at all.

Standard nutrition and ingredient labeling under 21 CFR 101 applies to packaged seaweed products. Nothing in it addresses iodine load per serving, which matters for thyroid-sensitive consumers eating kelp regularly.

Wild and farmed seaweed routinely arrives with epibionts — bryozoans, amphipods, small crustaceans. Whether that requires a crustacean allergen advisory has no clear federal answer, and buyers ask about it constantly.

Finfish and shellfish aquaculture have health-certification and movement-control expectations. Seaweed has essentially none, despite documented disease and epiphyte problems in production systems worldwide.

Nursery-to-farm seedstock transfer, gear movement between sites, and genetic provenance of cultivated strains are handled — where handled at all — through state permit conditions written for a different purpose.

Biosecurity is where food safety and ecosystem risk overlap, which is exactly why it keeps falling between agencies.