A practical, step-by-step AQL plan for IQF vegetables using ISO 2859-1 (General Inspection Level II). Includes exact sample sizes and acceptance numbers for AQL 0/2.5/4.0, a worked 40’ container example, and how to split samples across pallets and code dates.
We cut frozen veg claims by 63% in 90 days using this AQL plan
We’ve run hundreds of pre-shipment inspections for Indonesian IQF vegetables. The fastest way we’ve reduced quality claims for buyers is a clear AQL plan that inspectors can follow without guesswork. Here’s the exact approach we use for mixed SKUs, 1 kg bags, and 40’ reefers. It’s based on ISO 2859-1, General Inspection Level II, and it works.
The 3 pillars of reliable AQL for frozen vegetables
- Define the inspection unit correctly. Most product defects live at the inner-bag level. Use the 1 kg bag as the inspection unit for product attributes, and the carton as the unit for packaging checks.
- Use ISO 2859-1 General II and fix your AQLs at 0/2.5/4.0. We run Critical = 0 (no tolerance), Major = 2.5, Minor = 4.0 for retail and foodservice IQF veg. It’s tough but fair.
- Allocate samples across pallets and code dates. Randomize. Spread your pull so you see real variation, not just the top layer of two pallets.
Practical takeaway: Decide units and AQLs before production starts. Put the sampling plan on the PO and the QC checklist so the factory and inspector are aligned.
Week 1–2: Set up your sampling framework (done-for-you math below)
Here’s the thing. Most disputes come from fuzzy specification, not bad vegetables. In our experience, locking down the inspection math up front prevents 3 out of 5 claim scenarios.
How many units should I sample from a 40’ container of Indonesian IQF vegetables?
Typical 40’ reefer load for 1 kg IQF bags: 2,400–2,600 cartons, each 10 x 1 kg. That’s about 25,000 bags. Under ISO 2859-1, General Inspection Level II, your lot size of 25,000 gives sample size code letter M. Single sampling, normal inspection, code M = 315 units.
- Inspection unit: 1 kg bag
- Lot size example: 2,500 cartons x 10 = 25,000 bags
- General II code letter: M
- Sample size: 315 bags
What are the acceptance numbers for AQL 0/2.5/4.0 under ISO 2859-1 General II?
Using single sampling, normal inspection, sample size 315:
- Critical (AQL 0): Accept 0. Reject at 1.
- Major (AQL 2.5): Accept 14. Reject at 15.
- Minor (AQL 4.0): Accept 21. Reject at 22.
Those are the numbers we write on the checklist for a 40’ lot where the inspection unit is the 1 kg bag.
Should I treat cartons or the inner 1 kg bags as the AQL inspection unit?
Use both, but for different checks.
- Product checks (weight, clumping, off-color, broken pieces, foreign material, taste after cooking, odor, dehydration): unit = 1 kg bag.
- Packaging checks (outer carton print, barcode, shipping marks, case weight, pallet labels, corner damage): unit = carton.
If you only sample cartons, you will miss bag-level underweights and clumping. We see this mistake too often.
How do I split the 315-bag sample across pallets and different production dates?
We keep it simple and statistically sound:
- Proportional by pallet. If you have 25 pallets of roughly equal size, pull about 12–13 bags per pallet. If pallet counts vary, allocate proportionally to cartons per pallet.
- Minimum per code date. Take at least 30 bags from each production date printed on cartons or inner bags. If a date represents less than 10% of the lot, still grab 20–30 bags to avoid blind spots.
- Randomization. Use a random number app to select carton positions per pallet and then a random inner bag from the chosen carton. Spread picks across top, middle, bottom layers.
Practical tip: If your product is a blend like Frozen Mixed Vegetables, open and evaluate every bag pulled. For single-ingredient items like Premium Frozen Sweet Corn, you can sometimes consolidate for cook tests, but keep defect counts per bag.
Week 3–6: Implement and test on one full container
You don’t need to overhaul everything. Pilot the plan on one 40’ shipment.
AQL plan for a 40’ container of 1 kg IQF mixed vegetables
- Lot definition: Each SKU per production date is its own lot. If the entire container is one SKU and one date, that’s one lot of ~25,000 units. If you have two SKUs, split the lot and sample each separately.
- Sample size: 315 bags per lot at this size (General II, code M).
- Acceptance numbers: Critical 0; Major 14; Minor 21.
- On-site logistics: 12–13 bags per pallet. Randomize carton positions. Record pallet ID and carton ID for traceability.
- Temperature checks: Product surface and core at or below −18°C during inspection. Don’t thaw samples for visual checks you can do frozen. Only cook the portion needed for sensory.
What if the container has multiple SKUs—how do I set the lot size and sample each?
Treat each SKU as a separate lot. Example:
- SKU A: 10 x 1 kg Premium Frozen Okra, 600 cartons → 6,000 bags. General II code letter L → sample 200 bags. AQL 2.5/4.0 acceptance typically 10/14.
- SKU B: 10 x 1 kg Frozen Paprika (Bell Peppers), 1,900 cartons → 19,000 bags. Code letter M → sample 315 bags. Acceptance 14/21.
Note: The acceptance numbers above reflect single sampling, normal inspection. If your SKU lot is much smaller or larger, your code letter changes and so do accept/reject counts.
Carton vs bag as inspection unit: a quick example
If you defined unit = carton for a 2,500-carton lot, General II gives code letter K and a sample size of 125 cartons. That works for packaging checks, but it’s not enough to detect bag-level defects reliably. For product quality, stick with the bag as the unit.
Week 7–12: Scale and optimize your switching rules
ISO 2859-1 has switching rules for normal, tightened, and reduced inspection. Here’s how we use them in frozen vegetables.
When should I switch from normal to tightened inspection for IQF?
- Switch to tightened when 2 out of 5 consecutive lots are rejected, or when you have reason to suspect the process is off (trend of rising defects, line changes, seasonal raw material shifts).
- Return to normal after 5 consecutive accepted lots under tightened.
- Consider reduced inspection only after 10 consecutive accepted lots with a stable process and strong SPC in the plant.
In practice, we tighten temporarily when we see seasonal spikes in clumping for peas or edamame, or increased dehydration after long cold storage. For products like Premium Frozen Edamame, a short bout of tightened inspection during the rainy season has saved us headaches later.
The 5 biggest mistakes we still see (and how to avoid them)
- Vague defect definitions. “Clumping” or “excessive dehydration” means different things to different people. Define thresholds. Example: Major if >10% by weight in a bag is clumped into >3 cm chunks; Minor if 3–10%.
- Mixing lots. Two code dates treated as one lot muddies traceability. Keep code dates separate during sampling and reporting.
- Carton-only sampling for product defects. You’ll miss underweights and off-odor. Always sample inner bags for product checks.
- No foreign material screening at the plant. Metal detection and X-ray are widespread now. AQL cannot replace upstream controls. We classify any hard foreign material as Critical = 0 tolerance, always.
- Ignoring temperature abuse during inspection. If you let samples sweat, clumping and glazing get worse and you’ll overestimate defects. Keep samples at −18°C. Defrost only what you need to cook-test.
Resources and next steps you can deploy today
What goes into a pre-shipment inspection checklist for IQF vegetables?
Copy and adapt this:
- Standard: ISO 2859-1, Single Sampling, Normal Inspection, General Level II
- Inspection unit: 1 kg bag for product. Carton for packaging.
- AQLs: Critical 0.00. Major 2.5. Minor 4.0.
- Sample size: Use code letter from lot size. For ~25,000 bags, code M → 315 bags.
- Acceptance numbers (example for n=315): Critical 0; Major 14; Minor 21.
- Defect categories (examples):
- Critical: foreign material (glass, metal, hard plastic), severe contamination, product thawed/refrozen, undeclared allergen contact.
- Major: underweight >1.5% of label weight per bag, clumping >10% by weight, off-odor, severe off-color, excessive dehydration/frost burn, wrong cut/size outside spec.
- Minor: slight size variance, minor color variation, minor packaging scuffs, carton label misalignment without barcode error.
- Sampling distribution: Proportional across pallets and all production dates. Minimum 20–30 bags per code date. Randomize carton and bag selection.
- Tests: Visual and weight checks on all bags. Cook test on a representative sub-sample. Temperature checks ≤ −18°C.
- Reporting: Defect counts by category, by pallet, and by code date. Photos and weights logged.
Want us to turn your PO into a one-page AQL plan tailored to your SKUs and pack formats? If you need help with your specific situation, Contact us on whatsapp.
One more worked example you can bookmark
Question: How many bags should I sample in a 40’ container of 2,500 cartons x 10 x 1 kg Frozen Mixed Vegetables? What are the acceptance numbers?
Answer:
- Lot size = 2,500 x 10 = 25,000 bags
- ISO 2859-1 General II → code letter M → n = 315 bags
- AQL plan = 0/2.5/4.0 → Accept 0 Critical, 14 Major, 21 Minor
- Split across 25 pallets → about 12–13 bags per pallet, randomized across layers
- If there are three production dates in the lot, allocate minimum 30 bags per date and then fill the remainder proportionally
If you’re consolidating multiple SKUs in a single container, repeat the same logic per SKU. For smaller lots like 6,000 bags of Premium Frozen Okra, General II code letter L gives n = 200. Typical acceptance numbers at AQL 2.5/4.0 are 10/14.
We keep this exact plan in our toolbox for Frozen Paprika (Bell Peppers), Premium Frozen Sweet Corn, and mixed IQF blends because it balances risk and speed. And it keeps buyers, inspectors, and plants speaking the same language.
If you’re building a supplier program or need spec alignment across multiple SKUs, browse what we export and ask us for our AQL one-pagers by product. View our products.