Integrating Temperature and Time Indicators - The Skinner Larkin Curve

Timestrip’s liquid-based indicators provide an easy and effective way to monitor product conditions. Designed as smart, self-adhesive labels, they provide a clear visual signal when temperature breaches have occurred somewhere along the supply chain.

Cost effective and simple to use, the labels can be applied directly to a product or its packaging at the point of manufacture or collection, and remain in place until the item reaches the final user. Because the indicators are straightforward to activate and interpret, staff at any level who handle the product can easily use them.

However, when temperatures rise, the time at which a product may be stored often reduces. So Timestrip has developed Time-Temperature Indicators (TTIs) for this situation. When temperatures rise above recommended levels, the allowable time limit shortens accordingly.

This feature makes them particularly useful for safeguarding products such as seafood or other perishable foods, which spoil more rapidly at higher temperatures. High value pharmaceutical products also may have long shelf lives, but may be degraded much more quickly at elevated temperatures.

In the case of seafood, the indicators will provide a reliable indication when the food is stored above 37°F (3°C) – conditions in which they may develop Clostridium botulinum (C. bot) bacteria, responsible for food-borne botulism.

Left untreated, botulism can cause respiratory paralysis and even death. C. bot. is a naturally occurring bacterium that grows even in the absence of oxygen. It is commonly found in fish, especially in the gut and on the gills.

Skinner-Larkin curve

Scientific studies show that C. bot. produces toxin very slowly at lower temperatures and more quickly at higher temperatures. The time/temperature standard for when C.bot. toxin can form is known as the Skinner-Larkin curve (see chart 1 below).

Chart 1

Timestrip’s indicator TP255 is designed to approximate to the Skinner-Larkin curve.

Key Features of Timestrip Seafood Temperature Indicator:

• Breach time 2-4 hours
• Temperature Range: 3C / 37F
• Alert: colour change window

Seafood Temperature Indicator Benefits:

1. Unambiguous Temperature Breach: Time elapsed from the breach is indicated by blue in the 2nd window
2. Activation Feature: Can be shipped and stored at ambient temperatures
3. Traceable: Unique serial number on each indicator
4. Customisation Possibilities: Products and carrying cards can be customised for brands.
5. Designed with FDA Guidance

Timestrip TTI indicators provide a simple, cost effective method for dealing with the complex relationship between temperature and acceptable exposure time for sensitive products and materials.

For more information, contact us or email us at info@timestrip.com

Ref: J Food Prot. 1998 Sep;61(9):1154-60. doi: 10.4315/0362-028x-61.9.1154.

Conservative prediction of time to Clostridium botulinum toxin formation for use with time-temperature indicators to ensure the safety of foods.