A practical, importer-ready SOP for specifying, deploying, and verifying temperature data loggers in Indonesian frozen vegetable shipments. We cover setpoints, PTI, logger specs and placement, acceptance criteria, contract clauses, and what to do if there’s a breach.
If you can’t prove your frozen vegetables stayed at -18°C all the way from factory to your DC, you’re gambling with quality and claims. After years exporting IQF vegetables from Indonesia, we’ve built a simple system that buyers bookmark, auditors respect, and insurers accept. Here’s the exact SOP we use and recommend for Indonesian frozen vegetable data loggers.
We’ll use common SKUs like Premium Frozen Edamame, Premium Frozen Okra, Premium Frozen Sweet Corn, Frozen Mixed Vegetables, and Frozen Paprika (Bell Peppers) as examples, but the approach applies to most -18°C frozen vegetables.
The 3 pillars of a reliable data-logging program
- Specify clearly. Lock in reefer/PTI settings, logger specifications, calibration, and acceptance criteria in your PO or contract. Ambiguity is where most disputes start.
- Deploy smartly. Use enough loggers. Place them where they tell the truth about product temperature, not just air movement.
- Verify and act. Define what counts as a breach, the evidence you need, and the steps you’ll take with your supplier and insurer.
Phase-by-phase SOP (from pre-booking to arrival)
1) One week before stuffing: setpoints, PTI, and logger specs
What temperature should a reefer be set to for frozen vegetables?
- For IQF frozen vegetables, set supply-air setpoint to -18°C. Some buyers choose -20°C for a safety margin. Our default is -18°C unless your spec says otherwise.
- Fresh air exchange: 0%. Vent fully closed. Continuous air circulation on. Auto defrost on. High fan speed. Record the PTI printout.
PTI settings for frozen cargo. Ask your shipper to provide:
- Carrier PTI printout with unit number, setpoint, supply-air control mode, vent at 0%, and alarm-free status.
- Pre-cooling declaration. Product must be loaded already at -18°C or below. Never use the reefer to freeze product.
Data logger specs we trust and see accepted by US/EU buyers:
- Brands often accepted by insurers and retailers: Sensitech TempTale, Emerson GO, DeltaTrak, LogTag, ELPRO, Ellab. “Approved” lists vary, but these names reduce friction.
- Requirements: 12-month calibration certificate (ISO/IEC 17025 traceable), accuracy ±0.5°C at -20°C, IP65+ housing, 60–90 days battery at 10-minute intervals, PDF/CSV output without proprietary software, unique serials.
- When to use GSM loggers: When you need live visibility at transshipment. Great for risk control, but battery life and roaming cost matter. We still place at least one USB/PDF logger as independent evidence for claims.
2) Loading day: how many loggers and where to place them
How many temperature loggers do I need in a 40-foot container?
- Minimum 4. Better 5–6 for audit-grade proof. We use 5 as standard for 40RH frozen vegetables.
- Rule of thumb: 1 per 8–10 pallets or every 6–7 meters of load length.
Where should I place temperature data loggers inside the reefer?
- Logger A (nose/return-air zone): On the first pallet nearest the refrigeration unit, mid-height, shielded from direct airflow.
- Logger B (center mass): Inside a carton on a middle pallet, mid-height. This shows product-adjacent conditions. Many claims hinge on this.
- Logger C (center aisle): Between pallets at center, mid-height, not touching walls.
- Logger D (rear/door area): On a rear pallet, mid-height, shielded. Expect this to be the warmest point.
- Logger E (floor or top layer, center): If using a 5th, place floor-level at mid-load, or top layer center to capture vertical gradient.
Pro tip from experience. Start loggers 30–60 minutes before stuffing with a start delay so you avoid clutter from pre-staging. Photograph each logger’s location and serial number as you place it. Add a simple pallet map to the packing list. It’s the small details that win disputes.
Should I use dry ice or eutectic plates with reefer containers?
- For -18°C frozen vegetables in a powered reefer, no. Extra refrigerants can interfere with unit control and create unsafe CO2 levels. Only consider passive coolant if you knowingly face long no-power windows. In that case, use a genset instead.
Indonesian origin note. Terminals in Jakarta (Tanjung Priok) and Surabaya (Tanjung Perak) have dedicated reefer yards. We ensure plug-in timestamps are recorded on the EIR, and trucks move with gensets when required. Power continuity records matter during monsoon congestion.
3) In transit: interpreting reports and managing exceptions
How to interpret a PDF temperature logger report for reefer shipments:
- Check sampling interval. Ten minutes is ideal. Longer than 15 minutes hides spikes. Shorter than 5 minutes burns battery.
- Expect small defrost bumps. Supply/return air may rise 1–3°C briefly during defrost. Product-adjacent logger should stay stable.
- Look for time-above-threshold, not single spikes. For frozen veg, we set thresholds at -15°C and -12°C.
Door vs return air temperature difference in reefer monitoring:
- Return air reflects what the product “feels.” It’s more meaningful than supply-only readings. Door area is the warmest and will show higher variability, especially at transshipment. That’s normal within limits.
Acceptable temperature fluctuations for -18°C frozen vegetables during transit:
- Supply-air at setpoint -18°C ±2°C during steady state.
- Product-adjacent loggers remain ≤ -15°C for the entire voyage, with allowance for short transshipment spikes, not exceeding 2 hours above -15°C and never above -12°C.
- If your brand or buyer standard is stricter, put it in the PO. We can meet -18°C absolute with -16°C max spike on some lanes, but it requires tighter loading windows and costs more.
What counts as a temperature excursion for frozen vegetables?
- Define it contractually. Our default: any product-adjacent reading above -12°C for more than 60 consecutive minutes, or above -15°C for more than 120 consecutive minutes, is an excursion. Documented defrost cycles are not excursions if other loggers remain within limits.
4) Arrival: acceptance, documents, and claims
What documents should my Indonesian exporter provide to prove cold chain integrity?
- PTI printout with unit number and setpoint.
- Pre-cooling records and product core temperature checks at stuffing.
- Loading photos, logger serials and placement map, container and seal numbers.
- HACCP cold chain records and SOPs, including our temperature excursion policy and CAPA workflow.
- Logger calibration certificates and complete PDF/CSV reports.
- Power continuity records at port and any genset handovers.
How do I file a claim if the temperature logs show a breach?
- Do not break the cold chain unnecessarily. Move to a monitored cold store. Separate suspect pallets if needed.
- Notify insurer and carrier immediately. Request their reefer telemetry and alarm history.
- Engage a joint surveyor. Share your independent logger reports, PTI, photos, and placement map.
- Mitigate loss. Rework or salvage where safe. Keep a mitigation log.
- If breach ties to carrier performance, file a formal claim with both your independent logs and the carrier’s data. The combination is powerful evidence.
Template for temperature excursion CAPA with Indonesian supplier:
- Containment: quarantine affected pallets, extra QC checks, notify stakeholders within 24 hours.
- Root cause: five-why analysis on equipment, loading time, door openings, power continuity.
- Corrective actions: adjust staging time, add another logger at the weak zone, set tighter dispatch windows.
- Verification: next two shipments show stable logs, reviewed jointly.
Practical answers to the questions we get most
Which logger types do US/EU buyers accept?
- Single-use USB/PDF loggers remain the workhorse because they’re simple and auditable. Many retailers now ask for at least one real-time GSM unit per reefer for lane visibility. We often deploy a mix: 4 USB + 1 GSM.
How to calibrate temperature data loggers for frozen shipments?
- Use devices with ISO/IEC 17025 traceable certificates, calibrated near the operating range (0°C and -20°C points). Annual recalibration is standard. Keep certificates attached to your shipment file.
Sample purchase contract clauses requiring temperature loggers:
- “Seller shall load product pre-cooled to ≤ -18°C and set reefer supply-air setpoint to -18°C, vent 0%, continuous air, high fan.”
- “Seller shall place minimum five temperature loggers: nose, center carton, center aisle, rear door, and floor/top center. Provide serials, photos, and placement map with documents.”
- “Acceptable limits: product-adjacent loggers remain ≤ -15°C throughout transit; no period above -12°C longer than 60 minutes.”
- “All loggers shall have valid ISO/IEC 17025 calibration certificates. Reports in PDF/CSV must be delivered within 24 hours of arrival.”
What to do if temperature logger shows excursion at a transshipment port?
- Cross-check with carrier telemetry and the other loggers. A single door-zone spike during a brief unplug may not be product-impacting if center-carton remained stable. Escalate only if multiple positions show sustained warming.
Common mistakes we still see (and how to dodge them)
- Relying only on the carrier’s reefer data. It’s valuable, but independent loggers are your best evidence with insurers. Use both.
- Placing all loggers in the air stream. That overstates defrost effects. Always include one inside a carton and one at the door zone.
- No start delay. You’ll record ambient handling noise and bury the real story. Set a 30–60 minute delay.
- Sparse documentation. If it’s not photographed, mapped, and signed, it didn’t happen. Simple checklists win disputes.
When this advice applies (and when it doesn’t)
- Applies to -18°C frozen vegetables like our IQF Premium Frozen Sweet Corn, Premium Frozen Okra, and Frozen Mixed Vegetables. Also suits pre-fried SKUs like Premium Frozen Potatoes.
- Not ideal for fresh-chilled commodities like Tomatoes or leafy lines such as Baby Romaine. Those use return-air setpoints around +2 to +5°C and different logger placements.
Final takeaways you can put to work today
- Lock in -18°C supply-air, PTI proof, 0% vent, and high fan in your PO.
- Deploy five loggers in a 40RH as standard and map their positions with photos.
- Judge excursions by product-adjacent data and time-above-threshold, not isolated spikes.
- Keep a clean document pack: PTI, pre-cool, photos, map, calibration certs, logs, and power continuity.
If you’d like us to apply this SOP to your next shipment of Indonesian frozen vegetables, need a sample clause pack, or want our latest logger placement map template, just Contact us on whatsapp. You can also browse current SKUs and specs here: View our products.