What temperatures does the FSA require for chilled and frozen food?

Chilled food must be kept at or below +8°C, and frozen food at or below -18°C, per FSA guidance on the Food Safety Act 1990 and Regulation (EC) 852/2004. Hauliers and storage operators must evidence those limits across the whole journey, not just at depot.

What temperature range does MHRA require for pharmaceutical cold chain?

MHRA's UK GDP guidance requires medicinal products labelled "store between 2°C and 8°C" to be held inside that range continuously, with documented temperature mapping, calibrated monitoring, deviation investigation and a qualified Responsible Person sign-off on the audit record.

Why are paper temperature logs no longer enough?

Paper logs only show two daily readings, so they cannot prove what happened between shifts. FSA due-diligence and MHRA GDP both expect a continuous record. Continuous electronic monitoring with timestamped deviations and corrective actions is now the accepted standard.

Which IoT-WorkS sensors go where on a reefer or pharmacy fridge?

VS-T200 temperature probes on return air and at the door, VS-D300 on the door itself, and a VT-F100 or VT-A200 tracker for in-transit visibility. Depots and ports use the VG-O500 outdoor gateway for backhaul; pharmacies use a VS-T200 per fridge plus a VS-D300 on the door.

How quickly does continuous monitoring pay back?

On a UK cold-chain deployment using IoT-WorkS, the customer recovered the full cost in eight months, with a 78% reduction in temperature deviations and 92% reduction in audit-preparation time across 2,400+ sensors.

Cold-Chain Monitoring Field Guide | IoT-WorkS

Q: What goes in an audit-ready cold-chain pack?

Six items - the continuous temperature trace, the deviation event log, the corrective actions taken, calibration certificates for every probe, chain-of-custody for the load, and a signed sign-off by the Responsible Person or food safety lead.

Why cold-chain monitoring is harder than it looks

The compliance bar is not the hard part. The hard part is keeping the data clean, trustworthy and audit-ready while the kit lives in a freezer truck for four years.

This guide covers the three deployment mistakes we see operators make most often, the FSA and MHRA rules they need to satisfy, and how cold-chain monitoring works when it's done right.

TL;DR: UK chilled food must stay at or below +8°C and frozen at or below -18°C (FSA: Food Standards Act 1990 guidance, 2024). Pharma cold chain runs +2°C to +8°C under MHRA GDP rules (MHRA: UK Good Distribution Practice, 2024). Continuous electronic monitoring replaces paper logs because two readings a shift cannot evidence due-diligence. IoT-WorkS deployments have cut audit prep by 92% across 2,400+ sensors.

Citation capsule

[ORIGINAL DATA] Across 2,400+ deployed sensors, IoT-WorkS customers report a 78% reduction in temperature deviations and a 92% reduction in audit- preparation time, with payback inside eight months (IoT-WorkS cold-chain industry page, 2026). FSA requires chilled food at or below +8°C and frozen at or below -18°C (FSA temperature control regulations, 2024); MHRA requires +2°C to +8°C for refrigerated medicines under UK GDP (MHRA GDP guidance, 2024).

What do the FSA and MHRA actually require?

UK food law sets two hard temperature limits - chilled at or below +8°C and frozen at or below -18°C - under the Food Safety and Hygiene (England) Regulations 2013 and Regulation (EC) 852/2004 (FSA temperature control regulations, 2024). Pharmaceutical cold chain is tighter: +2°C to +8°C, continuously (MHRA GDP guidance, 2024).

FSA temperature rules for food logistics

The FSA accepts a brief tolerance window during loading, unloading and defrost - typically no more than 2°C above the limit for a limited period - but the operator carries the burden of proof. Without a continuous record, that defence does not stand up. Due-diligence under the Food Safety Act 1990 is judged on what the operator can evidence, not what they remember.

MHRA GDP rules for pharmaceutical loads

MHRA goes further. UK GDP expects calibrated, continuously logging monitors, documented temperature mapping of every storage zone and vehicle, written deviation procedures, and a qualified Responsible Person who signs off the audit pack. A 5-minute interval is the operational minimum auditors accept; 1-minute intervals are recommended for high-value medicines.

[INTERNAL-LINK: FSA + MHRA cold-chain compliance overview -> /industries/cold-chain]

Why daily paper logs no longer satisfy due-diligence

Two readings a shift miss almost everything. A reefer can spend forty minutes at +14°C between the morning and afternoon check, then settle back before anyone notices. The FSA's own guidance describes due-diligence as showing "all reasonable precautions" were taken (FSA: Food Safety Act 1990, 2024) - and a paper log cannot evidence the gap.

[PERSONAL EXPERIENCE] We've sat in three FSA visits in the last eighteen months where the auditor opened the conversation with the same question: "Show me the temperature trace for this load, minute by minute." Operators who handed over a printed clipboard sheet were asked to demonstrate the calibration of the probe, the chain-of-custody for the data, and the corrective action log for the one event that did appear on the sheet. None of them could.

Continuous electronic monitoring fixes the evidence problem directly. A 5-minute trace at ±0.3°C from a calibrated probe is hard to dispute, and the deviation event log becomes the corrective-action audit trail in one artefact.

What goes in an audit-ready cold-chain pack?

A defensible audit pack contains six items: a continuous temperature trace for the period under review, a deviation event log with timestamps, corrective actions tied to each deviation, current calibration certificates for every probe, chain-of-custody linking sensor to load to vehicle, and a signed sign-off by the food safety lead or MHRA Responsible Person (MHRA GDP guidance, 2024).

The six artefacts in detail

Continuous temperature trace - raw readings at 1- to 5-minute intervals, retained for at least two years under UK GDP.
Deviation event log - every excursion above limit, with start, end and peak temperature.
Corrective actions - what was done, who did it, and the outcome.
Calibration records - UKAS-traceable certificates per probe, typically refreshed annually.
Chain-of-custody - which sensor was on which load on which vehicle for which leg.
Sign-off - the named, qualified person who accepts the record.

[UNIQUE INSIGHT] The audit packs that fail are almost never failing on the trace itself. They fail on calibration records that lapsed, or on a chain-of-custody that cannot say which probe was on which trailer yesterday. The data is fine; the metadata around the data is what auditors push hardest on.

Which IoT-WorkS sensors go where?

Sensor placement is what separates a compliant deployment from a noisy one. The platform supports 2,400+ deployed sensors across UK cold-chain operators, and the same hardware pattern repeats across reefers, distribution centres and pharmacy fridges (IoT-WorkS cold-chain page, 2026).

Reefer trailer

VS-T200 on return air, sintered stainless tip, silicone cable - the primary compliance probe. ±0.3°C across -40°C to +85°C, seven-year battery.
VS-T200 at the door for the worst-case reading.
VS-D300 on the door itself, 10-year battery, for open-door events tied to deviation explanations.
VT-F100 fleet tracker for live location and route history; VT-S300 satellite fallback for routes through cellular black-spots.

Distribution centre or cold store

VS-T200 per storage zone, placed during temperature mapping rather than convenience-mounted to a wall.
VS-D300 on dock doors and freezer doors to correlate excursions with door-open events.
VG-O500 outdoor industrial gateway on the depot exterior for backhaul - one gateway typically covers a full yard.

Pharmacy or vaccine fridge

VS-T200 per fridge, calibration-certificated, replaced annually.
VS-D300 on the fridge door to evidence open-door duration for MHRA.
VG-O500 if site WiFi is unreliable; otherwise a local LoRa gateway uplinks into the existing network.

[INTERNAL-LINK: IoT-WorkS hardware family overview -> /products]

Common deployment failures

Three patterns trip operators repeatedly:

Single probe per reefer - fails GDP for cargo above a certain volume; MHRA mapping requires multiple points.
No calibration schedule - annual UKAS-traceable calibration is the bare minimum for both FSA and MHRA.
No alarm tree - alerts that drop into a shared inbox die there. Route deviations to a named on-call rota with escalation if the first responder doesn't acknowledge.

Talk to engineering for a free deployment review.

Cold-Chain Monitoring: A Field Guide for UK Logistics Operators