Verifying Laundry Wash Temperatures with LaundryStrip Temperature Indicator Labels
In food manufacturing, healthcare, and other regulated environments, washing protective clothing and workwear at the correct temperature is not just a hygiene preference — it is a legal and regulatory requirement. Pathogens including Salmonella, Listeria, E. coli, and Staphylococcus aureus can survive on fabric at low wash temperatures, and inadequately laundered workwear is a recognised contamination vector in food production environments. The LaundryStrip temperature indicator label provides a simple, cost-effective method of verifying that each wash cycle achieves and maintains the required thermal exposure to reduce microbial risk to acceptable levels.
This article explains how LaundryStrip labels work, where they are used, the regulatory requirements they support, and how to incorporate them into a documented laundry temperature monitoring programme.
The Importance of Laundry Temperature Validation in Food and Healthcare Environments
Protective clothing worn in food manufacturing — including coats, aprons, gloves, hairnets, and sleeve protectors — comes into direct or indirect contact with food products throughout the production process. If this clothing carries viable pathogens when workers return to the production floor after breaks, the potential for product contamination is significant. The same concern applies to clinical workwear in healthcare settings, where inadequately laundered garments can serve as a vehicle for healthcare-associated infection (HAI) transmission.
The temperature at which laundry is washed determines its effectiveness as a pathogen reduction step. Most vegetative bacteria — those without the protection of spore formation — are inactivated at 60°C, and extended exposure at this temperature achieves the microbial reduction required by most food industry standards and healthcare hygiene guidelines. Prion-contaminated garments require significantly higher temperatures and specific chemical treatments, but these represent a specialist case beyond the scope of standard workwear laundering.
The problem is that wash cycle temperature settings are not self-verifying. A washing machine programmed for a 60°C cycle may not actually reach 60°C due to element failure, limescale build-up, overloading, insufficient hot water supply, or calibration drift. Without a method of verifying that each cycle actually achieves its target temperature, the laundry process cannot be treated as a validated hygiene step.
How the LaundryStrip Label Works
The LaundryStrip is an irreversible temperature indicator label designed to be attached to a garment or placed inside a wash bag and subjected to the full wash cycle alongside the clothing being laundered. The label contains multiple windows, each calibrated to a specific temperature threshold relevant to laundry hygiene applications — typically covering the range from below effective microbial reduction temperatures to above the target wash temperature.
During the wash cycle, each window that reaches its rated temperature undergoes a permanent colour change. After the cycle is complete, the label is read: a window that has changed colour confirms that the corresponding temperature was reached during the wash. A window that has not changed colour indicates the corresponding temperature was not reached. This provides an immediate, objective record of the maximum temperature achieved in that wash cycle, and confirms whether the target hygiene temperature was met.
The colour change is permanent and irreversible — it cannot be induced by steam, pre-wetting, or other laundry process conditions, only by the true thermal exposure experienced during the cycle. This makes the LaundryStrip a reliable and tamper-evident verification tool.
Placement and Use
LaundryStrip labels are typically attached to the inside of a garment near the collar or waistband, or to a small fabric tab that is folded inside a wash bag with the load. The label must remain in contact with the clothing and exposed to the full wash temperature — it should not be shielded from hot water by excess fabric or by placement at the periphery of an overloaded drum.
For a documented monitoring programme, a label should be used in each wash cycle, or at a minimum frequency defined in the facility's HACCP plan or hygiene management procedure. After the cycle, the label is read by the laundry supervisor or hygiene manager, the result is recorded (pass/fail against the target temperature), and the label is either attached to the record sheet or retained with the wash cycle log. Failed cycles — where the target temperature was not reached — should trigger an investigation of the washing machine's performance and a repeat wash before the garments are returned to use.
Regulatory Context
In the food manufacturing sector, the BRC Global Standard for Food Safety (Issue 9) requires documented evidence that laundry processes achieve the temperatures necessary to reduce microbial contamination to acceptable levels. BRC Issue 9 Clause 7.2 specifically addresses workwear laundering and requires either in-house or contracted laundry to be able to demonstrate that adequate wash temperatures are consistently achieved. The LaundryStrip provides the per-cycle evidence required to satisfy this clause during BRC audits.
SALSA (Safe and Local Supplier Approval) and the SQF Food Safety Code make similar requirements for smaller food manufacturers. NHS healthcare laundry specifications, including the Health Technical Memorandum HTM 01-04, specify minimum wash temperatures and hold times for different categories of linen and workwear, and require records demonstrating consistent achievement of these parameters.
In the UK, the Food Hygiene Regulations (England) 2006 and equivalent devolved legislation require food business operators to maintain written procedures based on HACCP principles, covering all steps in the production process with a potential food safety impact — including the management of workwear hygiene. Laundry temperature monitoring with a documented record provides auditable evidence that this HACCP element is effectively controlled.
In-House vs. Contracted Laundry Services
Food manufacturers and healthcare facilities can choose to launder workwear in-house or through a contracted commercial laundry service. In both cases, the requirement to demonstrate adequate wash temperatures applies.
For in-house laundry, the LaundryStrip can be incorporated directly into standard operating procedures, with labels applied to a designated indicator garment or wash bag in every cycle. For contracted laundry services, the contractor should be able to provide evidence of wash temperature achievement — either through their own monitoring records or by accepting LaundryStrip labels submitted with each batch of laundry. Some contracts specify this requirement explicitly; others rely on the contractor's own quality management system documentation.
Where contracted laundry records are relied upon, it is good practice to conduct periodic independent verification using LaundryStrip labels submitted with selected laundry batches, without prior notice to the contractor. This provides objective evidence of the contractor's actual performance independent of their self-reported monitoring data.
LaundryStrip in HACCP Documentation
For HACCP documentation purposes, the LaundryStrip monitoring programme should include a description of the critical control point (wash temperature) and the critical limit (e.g., minimum 60°C), the monitoring method (LaundryStrip label, read after each cycle), the monitoring frequency (every cycle, or as specified), the corrective action procedure for out-of-specification results, the record format (log sheet or digital record), and the verification and review schedule (periodic review of monitoring records, equipment calibration checks).
Temperature Indicators Ltd can provide guidance on documenting the LaundryStrip programme within your HACCP plan, and can supply the labels in pack sizes appropriate for high-volume in-house laundry operations.
Frequently Asked Questions
What temperature does the LaundryStrip verify?
LaundryStrip labels are available in configurations covering laundry hygiene temperature ranges, with the most commonly specified target being 60°C for food industry and general healthcare workwear. Higher-temperature variants are available for applications requiring verification of 65°C or 71°C cycles, as specified in some NHS laundry guidance for high-risk items. Contact Temperature Indicators Ltd to confirm the correct variant for your target wash temperature.
Can a single LaundryStrip be used for multiple wash cycles?
No — LaundryStrips are single-use. Once a window has changed colour, it has permanently recorded that temperature and cannot be reset. Using the same strip across multiple cycles would make it impossible to determine which cycle achieved — or failed to achieve — the target temperature. Use a fresh strip in each monitored cycle.
Does the LaundryStrip work in all washing machine types?
LaundryStrip labels are suitable for use in domestic, commercial, and industrial front-loading and top-loading washing machines. They are designed to withstand the mechanical agitation, water immersion, and detergent chemistry of a standard wash cycle while accurately recording thermal exposure. They are not suitable for use in dry-cleaning processes, as these use solvents rather than hot water and would not register a thermal event.
How are LaundryStrip monitoring records used in a BRC audit?
BRC auditors will ask to see evidence that laundry processes consistently achieve the required temperatures. LaundryStrip monitoring records — showing the strip readings, dates, wash cycle identification, and any corrective actions taken for out-of-specification results — provide this evidence directly. Records should be organised by date and retained for the period required by your quality management system, typically a minimum of twelve months for BRC Food Safety compliance.
What should I do if a LaundryStrip shows the target temperature was not reached?
First, quarantine the garments from that cycle and do not return them to use until they have been successfully re-washed and the re-wash has been verified with a fresh LaundryStrip. Then investigate the washing machine: check the temperature setting, inspect the heating element and thermostat, check for limescale build-up, and verify that the machine was not overloaded. If the machine cannot be confirmed as operating correctly, take it out of service until it has been inspected and repaired. Record the non-conformance and the corrective action taken.
About Temperature Indicators Ltd
Temperature Indicators Ltd is a specialist global distributor solely focused on temperature-sensitive labels, tags, and indicators for cold chain monitoring, process validation, and regulatory compliance. With 35 years of experience and operations shipping to over 50 countries worldwide, we supply food manufacturers, pharmaceutical distributors, sterile services departments, and logistics providers with the temperature monitoring solutions they need to maintain compliance. Contact us for expert guidance on temperature monitoring for your application.
Legal Disclaimer
The information provided in this article is for general guidance only. Temperature Indicators Ltd makes no warranties, express or implied, regarding the accuracy or completeness of this content. Product specifications, regulatory requirements, and industry standards may change over time. Always verify current requirements with the relevant regulatory authority and consult a qualified professional before making decisions based on information contained in this article. Temperature Indicators Ltd accepts no liability for actions taken in reliance on information provided here.
- Temperature Indicators Staff
