How to Monitor Time/Temperature in the Food and Beverage Supply Chain
A variety of “smart” label technologies exist that give a clear indication of product freshness and quality.
Quality and safety are two of the key requirements in the food manufacturing supply chain-from packaging, distribution and food retailing through to the consumer. This, in turn, has lead to a growing demand for more information on the packaging so consumers can easily recognize when food is at its nutritional best and safe to eat, or when it should be disposed of to avoid ill health. Legislation on front-of-pack labeling, for example, now calls for clearer information on, say, nutrition and variations on “use by,” “sell by” and “use within” dates.
Similarly, in food retailing, there is an ongoing demand to better manage shelf life and environmental conditions-and again to provide a clear visual guide of “food freshness” for consumers.
The challenge for anyone in the food supply chain is that the deterioration of temperature-sensitive or time-temperature-sensitive foods starts immediately after the product has been processed and packed and will then largely depend on how well the cold chain can be maintained.
Temperature checks at the various points in the supply chain will verify that the stipulated “use by” date can still be trusted, but how does the manufacturer/supplier take into account any temperature abuse between checks? Ultimately it stops at the retailer, although ideally it should continue with the consumers’ handling of the goods to and in the home.
Ongoing and new advances in different forms of temperature or time/temperature indicators and monitors include devices that report a visual and straightforward summary of the time/temperature exposure history of foods and beverages.
One of the initial manufacturers of time/temperature indicators (TTI) was 3M. Today, the company’s Monitor Mark indicator provides an affordable and widely used solution for the monitoring of products that are sensitive to time/temperature abuse, offering an easy-to-read irreversible signal that estimates the time the threshold temperature has been exceeded. Able to monitor a range of food and beverage products, the Monitor Mark has a pressure-sensitive backing that allows convenient attachment to most clean, dry surfaces and is primarily used within secondary packaging, such as a case or box.
Another 3M indicator, Freeze Watch, uses a unique design to provide a clear visual indication that products have been exposed to freezing temperatures. It offers a reliable freeze alert system, based on a specially designed ampule that contains highly-sensitive liquid. The ampule fractures at a certain freeze point, releasing liquid that stains the paper behind it, providing an obvious indicator. These indicators are available at two temperature levels: 25° F. (-4° C.) and 32° F. (0° C.).
In 2005, a new company appeared, Timestrip. It already has a comprehensive range of clients for its time/temperature and freeze indicators across the world.
This company’s core technology is an inexpensive and easy-to-use smart label that monitors elapsed time and is easily adapted for numerous applications in the monitoring of product shelf life and environmental conditions. It is suitable for products which have a “use by” or “use within” date, providing an accurate food freshness indicator that adheres directly to fresh or frozen food packaging-or home re-packaging-for clear, visual monitoring of product shelf life. It can also act as a helpful reminder by providing a clear visual guide for the consumer.
As a result, food waste is reduced and consumers’ have greater confidence in the product. In addition, the Timestrip label acts as an anti-counterfeiting and tamper-evident device for manufacturers, helps to eliminate confusion over “use within” dates and adds brand value.
A new product from the company iStrip identifies if an accidental freezing event has taken place in the cold chain, whereon it irreversibly changes color if exposed to freezing conditions. iStrips can be applied as a standard label and have an adaptable freezing point.
Many time/temp indicators are developed for fresh products. The TXi time/temperature monitoring label from PakSense, for example, is currently being rolled out by JBS Swift & Co. on packs of fresh beef and pork in North America.
About the size of a sugar packet, the flat TXi label is able to digitally record time and temperature of a product’s environment during distribution, for up to eight weeks. Acceptable temperature ranges are pre-programmed into each label by PakSense and can be customized for each application, such as meats, seafood or produce. The user simply snaps the corner of the label to activate it and attaches it to the product. Labels, each identified by a unique serial number, are encased in food-grade packaging and are waterproof.
An LED light (green for good, yellow for suspect) provides a quick visual indication on whether appropriate temperatures were maintained during shipping. Additionally, all temperature readings stored in the non-volatile memory of the PakSense TXi label can be downloaded at any time via the PakSense Reader into a Microsoft Excel spreadsheet. Labels can also be stapled to shipping paperwork for those who wish to file temperature information with a bill of lading or other documentation.
To increase awareness of handlers throughout the supply chain and deter mishandling, Environmental Indicators from ShockWatch provide a proactive approach.
At the end of the line, the Environmental Indicators system informs shipment recipients of the product’s status and identifies necessary steps to take if the indicator is activated. But it also alerts handlers that the shipment is being watched-providing reinforcement to deter mishandling.
Each of ShockWatch’s five uniquely designed Environmental Indicators-ColdMark, WarmMark, WarmMark Duo, WarmMark Long Run and HeatWatch-determine shipment status immediately.
The user-friendly indicators adhere to environmentally sensitive products. Highly visible companion labels are placed on the outside of the box or case to give recipients a quick, definitive answer on whether the shipment has met environmental standards during transit. If not, an insert card reminds the user of appropriate courses of action. Additionally, companion labels come with a tear-away record for recipients to log any issues and hold carriers accountable.
To help optimize shelf life of perishable foods and beverages, Ciba Specialty Chemicals and FreshPoint jointly developed OnVu time/temperature indicators. They’re designed for meat, fish and convenience products with a shelf life of five to six days at 41° F. or for products with a shelf life of between four and 14 days at 32° F. to 39° F.
The OnVu technology relies on the properties of pigments that change color over time and if temperatures fluctuate. Once activated by an ultraviolet light source, the TTI first becomes dark and then grows progressively lighter as time passes, and also if and when the ambient temperature rises. Exposure to higher temperatures than those prescribed accelerates the lightening process. When the activated color attains the same shade as the reference, the product has reached the end of its shelf life.
OnVu indicators can be supplied as labels or printed directly on the package.
Thermochromatic inksOther developments include using thermochromatic (color changing) ink dots to indicate that products are at the correct temperature for serving following refrigeration or microwave heating. For example, plastic containers of pouring syrup in the United States that are labeled with a thermochromatic ink dot will indicate that the syrup is at the right temperature following microwave heating.
Similar examples can be found on supermarket shelves with beer and wine labels. And some fruit drink containers incorporate thermochromatic-based designs to inform the consumer when a refrigerated beverage is cold enough or at the optimum temperature to drink.
Similar technology has been developed in Israel, where thermochromatic dyes which change color in response to exposure to pre-determined temperature over time, are finding commercial application in new types of time/temperature indicators. These new labels change color irreversibly and warn the user when a product has been exposed to a temperature/time profile that has damaged it.
Unlike other time/temperature labels available today, these new labels can be stored at room temperature before being “triggered,” and the simple manufacturing process allows for an affordable price.
Developments in time/temperature and other “smart” label technologies are bringing increasing certainty to the food supply chain and are undoubtedly moving further towards a world where consumers can be sure-and see for themselves-that the food they buy, store and use is of the right quality and freshness.
SEE FOR YOURSELF
More innovative smart label solutions will be on display at Labelexpo Americas in September 9-11, and will also be part of the conference program. To learn more about this evolving “smarter” world of labels, visit the show.
For more information
Ciba Specialty Chemicals
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