A frozen surimi block is the raw-material format the surimi industry actually trades in: washed, refined fish protein blended with cryoprotectants and frozen into rectangular blocks — most commonly around 10 kg each, packed two to a carton — that travel the world at −18 °C or below and become crab sticks, fish balls, chikuwa and fish snacks at their destination. If you are buying surimi products, or specifying them for OEM production, understanding this format explains most of the price and texture differences you will meet downstream.
We have worked with surimi as a manufacturer in Samut Sakhon, Thailand since 1994 — more than 30 years and over 4,000 tonnes of finished product a year — so this guide covers what block buyers and product buyers alike should know.
What exactly is in a surimi block?
Short answer: concentrated myofibrillar fish protein, water, and a cryoprotectant system — typically sugar and phosphates — added so the protein survives frozen storage with its gelling ability intact. No flavour, no colour, no starch yet.
The block is deliberately unfinished. It is a functional ingredient, not a food: neutral in taste, pale in colour, and valued almost entirely for how strong a gel it forms when salt is added and the paste is heated later. That gelling ability is what the cryoprotectants protect — freeze the protein without them and it arrives at the destination factory unable to set properly, which is the difference between a springy crab stick and a mushy one.
How are surimi blocks graded?
Short answer: by gel strength, whiteness and impurity count, into grades usually labelled along the lines of SA, FA, A and downward. Species matters too — cold-water Alaska pollock sets the global benchmark, while tropical species such as threadfin bream (itoyori) are the workhorses of Southeast Asian production.
The practical meaning of grade for a buyer:
| What the grade reflects | Why it changes your product |
|---|---|
| Gel strength | Decides the bite — high-gel surimi gives the clean snap premium markets expect |
| Whiteness | Sets how bright the finished product looks without heavy colouring |
| Impurities (specks) | Visible dark specks in a white product read as poor quality instantly |
| Species and catch handling | Determines all three above and the price per tonne |
Two finished products with identical ingredient lists can be built from different grades, and the difference shows up in the mouth, not on the label. When comparing suppliers of finished surimi products, asking which grade and species they buy tells you more than the quotation does.
How should frozen surimi blocks be stored and handled?
Short answer: continuously at −18 °C or colder, with temperature fluctuation treated as the real enemy. Time in storage matters far less than stability of storage.
A freezer that cycles up and down does more damage than a steady one running twice as long, because each partial-thaw lets ice crystals regrow larger and cut through the protein network. Once gel strength is lost this way it does not come back. The handling rules that follow from this:
- Keep the cold chain unbroken from the producing plant to your production floor — including the truck and the dock.
- Thaw under controlled refrigeration on a planned schedule, not at ambient temperature under time pressure.
- Never refreeze a thawed block; plan batch sizes so thawed material is used.
- Record temperatures at handover points — most disputes about “bad surimi” are actually disputes about an undocumented cold chain.
What should an importer or product developer specify?
Short answer: species, grade, gel strength range, block and carton format, and the cold-chain terms — in writing. A price per tonne without those five items is not comparable to any other price per tonne.
For customs purposes, frozen surimi is classified under HS chapter 03 (frozen fish meat, heading 0304), with the exact subheading depending on species and preparation — confirm the code with your customs broker per destination rather than copying it from another shipment, because duty treatment can differ.
If your real goal is a finished product rather than raw material, the same specification logic applies one level up: the factory you choose is making these block-buying decisions on your behalf, and its choices become your product’s texture and cost. This is exactly why our own OEM process starts with product development and a prototype-sampling stage within four weeks — the grade decision gets tested in your actual product before full-scale production, not assumed.
Frequently asked questions
Is a surimi block ready to eat?
No. It is an intermediate ingredient that still needs formulation (salt, starch, flavour), forming and heat-setting to become a food.
Why is Alaska pollock surimi more expensive than tropical surimi?
Higher gel strength and whiteness from cold-water species, plus supply economics. Tropical surimi such as itoyori is not “worse” — it is a different tool, and many excellent products blend the two.
How long can a block stay in frozen storage?
Held stable at −18 °C or below, many months with functionality intact. The honest answer is that stability of temperature, not elapsed time, is what determines it — which is why storage records matter more than dates alone.
Can we buy blocks directly and have someone process them?
Yes — that is toll processing. But unless you have surimi expertise in-house, an OEM arrangement where the factory owns raw-material selection against an agreed specification usually produces fewer surprises.
Does block format matter, or only grade?
Format matters operationally: block weight and carton configuration must suit the destination factory’s thawing and batching process. It is a small detail that becomes a daily annoyance if ignored.
Big Kitchen is an OEM manufacturer of fish snacks and frozen surimi products in Samut Sakhon, Thailand — fish strips, fish chips, squid sheets, imitation crab, fish balls and chikuwa — operating a facility certified to FSSC 22000, HACCP, GMP and HALAL and exporting to more than 14 countries including Korea, Japan and China. If you are specifying a surimi product and want the grade conversation handled properly, see our OEM service and product range, or contact the team.
Last updated: August 2026 · Written by the Big Kitchen production team
Related services & references
Learn more: OEM manufacturing service · Fish snack & surimi product range · About Big Kitchen · Contact the team
Standards referenced (official sources): FSSC 22000 · Codex Alimentarius (FAO/WHO) · Thai FDA