In any kitchen that uses a deep fryer—restaurant, fast-food outlet, snack bar, school cafeteria, nursing home, community center, caterer, or food processing facility—monitoring the quality of frying oil is both a health requirement and a major economic issue. Oil that is too old degrades the taste, is detrimental to the health of diners (appearance of toxic polar compounds, trans fatty acids), and can lead to HACCP non-compliance during a veterinary inspection. Conversely, changing it too soon means wasting a significant amount of money. 3M LRSM test strips provide a simple and objective solution to this dilemma: in 30 seconds, a color change from blue to yellow precisely indicates the level of oil degradation, allowing you to confidently decide whether to keep it or change it. It is the long-standing standard for frying oil quality control in the professional food service industry.
What exactly does the 3M LRSM tester measure?
LRSM = Low Range Shortening Monitor. The strips measure the concentration of Free Fatty Acids (FFAs) in the oil—compounds that form during the oxidation of triglycerides under the influence of heat, humidity, and repeated cooking cycles. The older the oil, the higher the FFA levels. Each of the four blue reactive bands changes from blue to yellow when a specific FFA threshold is reached.
| Strip (from the one furthest from the red line to the closest) | AGL Threshold |
| Band 1 | = 1.0% |
| Band 2 | = 1.5% |
| Band 3 | = 2.0% |
| Band 4 | = 2.5% |
This should be considered in light of the cost of a frying oil bath (20 L at €25-40 excluding VAT) renewed judiciously: a single oil change saved per year more than covers the cost of the strips. The financial benefit becomes even more significant for a restaurant chain.
Recommended storage for the tester
For normal daily use: store at room temperature, in the tightly closed tube, away from moisture.
For long-term storage (emergency stock): store in the refrigerator in the original closed tube.
Cold weather can cause a slight discoloration (blue? pale green) which is reversible and has no impact on effectiveness.
Always close the tube tightly after each sample: moisture degrades the reagents.
Check the expiry date indicated on the tube.
Concrete advantages of the LRSM tester
- Easy to use: requires no training
- Fast: immediate test result (30 seconds after immersion)
- Objective: the result is independent of the person performing the test
- Hygienic: the test strip cannot contaminate the oil being tested
- Precise: allows oil to be discharged at a precise level
- Reassuring: ensures that dietary rules are followed