Stop losing yield to vague tuna specs. Here’s a practical crosswalk for Indonesian yellowfin tuna loins that maps Trim A/Trim B, center-cut/back/belly, grade definitions, bloodline tolerances and size ranges into clear wording you can paste straight into your PO and your receiving checklist.
If you’ve ever received yellowfin loins that looked great on photos but bled yield on the cutting table, you’re not alone. We’ve watched buyers lose 5–12% margin simply because “Trim A” and “Grade A” meant different things to the plant and to the receiver. The fix is simpler than most people think. Define trim and grade in measurable terms, and verify them consistently.
Below is the crosswalk we recommend for Indonesian yellowfin tuna loins. It’s the same language we put in our purchase orders and receiving checklists when we want zero ambiguity.
What does “Trim A” really mean for Indonesian yellowfin loins?
In our experience, Indonesian processors generally use Trim A to signal a clean, ready-to-portion loin. But labels vary by plant. Spell it out like this:
- Trim A definition for PO: Skinless, boneless, belly-off unless otherwise specified. Bloodline-off with ≥95% removal. Residual dark meat halo not to exceed 3 mm thickness or 5% of cross-section surface area. Lateral line trimmed flush. No belly membrane or silver skin remaining.
- Defect tolerance: No skin, scales, bones, pin bones, or finlets. No parasites visible. Gaping allowed ≤5 mm width and ≤30 mm length, max 2 occurrences per loin. No oxidation or brown patches; color uniform deep red to cherry red. No cooked edges from temperature abuse.
Takeaway you can use: Don’t accept “Trim A” without quantitative bloodline, gaping, and color descriptors. That’s where most yield slips happen.
How is Trim B different and when is it acceptable?
Trim B is fine for steaks and cooked programs, but it’s risky for saku and premium sear. Define it like this:
- Trim B definition for PO: Skinless, boneless. Partial bloodline removal allowed. Remaining bloodline band ≤10–15 mm at widest point. Belly connective tissue and minor silver skin permitted. Tail taper allowed.
- Defect tolerance: Gaping ≤10 mm width and ≤50 mm length, max 4 occurrences. Color may vary from red to pinkish red. No brown or grey oxidized areas >1 cm².
When it’s acceptable: cooked steaks, cubes, or ground applications. If you want a ready-to-serve raw or sear-driven program, Trim B will cost you yield and complaints.
Does “bloodline off” mean 100% removal?
Practically, no. You’ll always see a faint halo where dark meat transitions. We specify either of these quantifiable options in POs:
- Option A: “Bloodline removal ≥95%. Residual halo ≤3 mm thickness across cut face.”
- Option B: “Residual dark meat area ≤5% of cut face surface area.”
Pick one method so your QA and your supplier measure the same way. We’ve found Option A is easier to verify visually with a ruler on a thawed cross-section.
Center-cut, back loin, belly loin and tail pieces. What’s the difference?
Here’s the thing. A “loin” isn’t one uniform piece. Yield and application change by location.
- Back loin (upper/above spine). Leaner, firmer, deep red color. Great for saku and sashimi blocks if center-cut. Lower visible sinew.
- Belly loin (lower/ventral). Slightly higher fat, can carry more sinew and connective tissue. Excellent flavor and sear, but requires tighter trimming for raw.
- Center-cut. The middle section of the loin with minimal taper. Uniform thickness for sashimi and premium portions. For PO: “Center-cut only, length 20–35 cm, width 6–9 cm, thickness 4–6 cm, taper <10% end-to-end.”
- Tail pieces. Tapered posterior sections with more sinew. Best for steaks, cubes, or ground.
If you care about saku yield, explicitly request “center-cut from back loins.” If you accept mix-of-cuts, you’ll see more tail and belly pieces in the box, which can be totally fine for cooked programs.
How do I write a clear grade and trim spec in my PO?
Here’s a copy-paste PO spec block we use for Grade A sashimi/sear programs. Adjust numbers to your tolerance.
PO Spec Template (Grade A, Trim A, Center-cut):
- Species/origin: Yellowfin tuna (Thunnus albacares), Indonesia. Non-CO treated.
- Cut/trim: Center-cut loin, back-loin preferred. Trim A. Skinless, boneless, belly-off. Bloodline removal ≥95%, residual halo ≤3 mm.
- Size range: 1–2 kg and 2–3 kg packs. No piece outside stated range. Sort and label by range.
- Color/appearance: Uniform deep red to cherry red. No brown/grey oxidized areas >0.5 cm². Surface dehydration ≤2 mm.
- Gaping/defects: Gaping ≤5 mm width and ≤30 mm length, max 2 per loin. No skin, scales, bones, or parasites visible.
- Odor: Clean, ocean-fresh. No sour, ammonia, or rancid notes.
- Temperature at loading: ≤ -18°C core.
- Packaging/label: Clearly state trim, grade, size range, production date, and lot number. Include pre-shipment photos of cross-sections.
If you’re not sure what tolerances match your yield targets, we’re happy to talk it through and tune per application. Need a quick sanity check for your current program? Contact us on whatsapp.
Mapping supplier grade AA/A/B to buyer spec
Letter grades aren’t standardized. We map them like this, then enforce numeric tolerances:
- Supplier AA. Typically sashimi-grade center cuts. Maps to our Grade A template above, sometimes with even tighter color/defect tolerances.
- Supplier A. Good for sear and premium foodservice. Often needs bloodline tolerances checked. May include some non-center-cut pieces.
- Supplier B. Steak/cook programs. Align with our Trim B definitions to avoid disputes.
Always anchor the PO to measurable definitions. Use the supplier letter grade only as a reference.
What size ranges are standard for export yellowfin loins from Indonesia?
Most plants sort by these common ranges:
- 1–2 kg. Very popular for retail and smaller saku programs.
- 2–3 kg. Bread-and-butter for foodservice and saku block yields.
- 3–5 kg. Less common but great for larger saku and steak cutting.
If your spec says “1–3 kg,” expect a mix of both sub-ranges. If you care about uniformity on the cutting line, specify the exact range and the allowed percentage in each. For example: “2–3 kg only. No more than 10% pieces 1.8–1.99 kg.”
How can I verify trim and grade on arrival without opening every carton?
Here’s a tight, low-effort receiving plan we’ve refined with buyers:
- Sampling. Open 1 carton per pallet plus 1 additional carton for the lot. If the lot is ≤5 pallets, open 2 cartons total. Use ANSI/ASQ Z1.4 if you need a formal plan.
- Temperature. Check core temp of 1 piece per opened carton with a calibrated probe. Record and photograph.
- Visual color check. Thaw one piece partially in the cooler just enough to inspect. Photograph cut faces. Compare to your color standard photo.
- Bloodline and trim. With a ruler, verify the residual halo thickness or area against your PO tolerance. Count gaping occurrences and measure width/length on the largest gaps.
- Documentation. Photograph label showing trim/grade/size and the cross-section of inspected pieces. Note any out-of-spec findings with measurements.
If more than 1 piece per inspected carton fails any single tolerance, escalate to a wider sampling. This approach catches most substitution without tearing through the entire lot.
Common mistakes that kill yield (and how to avoid them)
We see these over and over:
- Vague “Trim A.” Fix it with numeric bloodline and gaping limits.
- No cut-location control. Ask for “center-cut” explicitly if you want saku yield. Otherwise tail pieces creep in.
- Belly-on ambiguity. Write “belly-off” or “belly-on allowed” in the trim line. Belly-on boosts flavor but adds sinew and trimming.
- Size spread too wide. Split 1–2 and 2–3 kg, or your line will chase uniformity all day.
- Relying on letter grades. Use them as shorthand, but always attach the numbers.
What’s interesting is a recent trend in the last six months. More retail and foodservice buyers are requesting “non-CO treated” language for yellowfin and adding a quick metmyoglobin or color verification step. We support that. Put “Non-CO treated” in the PO and ask for a production declaration.
When Trim B makes sense (and what to buy instead of fighting the trim)
If your program is cooked steaks, kebabs, or cubes, Trim B can save money without sacrificing plate appeal. Pair that with portion control from the start and you’ll keep consistency.
- For cooked steaks, define Trim B plus a tighter tail exclusion if you hate taper. Or just move to pre-portioned Yellowfin Steak.
- For poke or sushi where you don’t want to manage trim, buy saku blocks directly. See our Yellowfin Saku (Sushi Grade).
- For value-added or industrial uses, spec Trim B and convert trimmings into Yellowfin Ground Meat (IQF). If you want a fattier profile, consider Bigeye Loin on specific runs.
If you’d rather browse finished formats and cut ideas before writing specs, you can always View our products for inspiration.
Quick-reference: phrases you can paste today
- Trim A, sashimi/sear: “Skinless, boneless, belly-off. Bloodline-off ≥95% removal. Residual halo ≤3 mm. Center-cut only. Gaping ≤5 mm × ≤30 mm, max 2 per loin. Deep red to cherry red. Non-CO treated.”
- Trim B, cooked/steak: “Skinless, boneless. Partial bloodline allowed ≤15 mm band. Gaping ≤10 mm × ≤50 mm, max 4 per loin. Tail taper allowed. Red to pinkish red.”
- Size control: “Size range 2–3 kg only. No pieces outside range. Label cartons by size.”
- Back vs belly: “Back-loin center-cuts only” or “Belly-on permitted” depending on your program.
Final thought. Spec clarity is boring until it saves you a container’s worth of margin. We’ve found that two small changes make the biggest difference. Force a numeric bloodline tolerance and call your cut location. Do those and the rest of your program gets easier.