Food Spoilage: Chinese Research Team Develops New Smart Tag

Most people throw out food rather than take a risk of contamination or spoilage beyond the expiration date presented on the package. In many cases, the food is still okay to consume after the date indicated but out of understandable fear, the response is to get rid of it. This is no longer necessary, as a Chinese research team has found a way to determine the freshness of canned foods and dairy products without the upleasantness associated with that smell test we all know so well and without even opening the package!


Bad Smell: Source: Smell: Source:


What is The American Chemical Society?

 According to a report presented at the  recent 247th National Meeting & Exposition of the American Chemical Society (ACS), a new, color-coded smart tag on the packaging of food products can tell consumers if their canned goods and dairy products have turned sour. This same tag can be utilized to determine the freshness of medications and other products that are considered perishable.


Food Spoilage Tag: Source: redorbit.comFood Spoilage Tag: Source:


A non-profit organization chartered by the United States Congress, ACS boasts more than 161,000 members. It is the world's largest scientfic association, with main offices in Washington, DC and Columbus, Ohio. The recent meeting, which was held at the Dallas Convention Center, was attended by thousands of scientists from all over the world and featured more than 10,000 reports on scientfic advances.


In the words of Chao Zhang, PHD, of Peking University in Beiijing, China, the lead reseracher in this project of developing food deterioration tags:

"This tag, which has a gel-like consistency, is really inexpensive and safe, and can be widely programmed to mimic almost all ambient-temperature deterioration processes in foods...And a real advantage is that when manufactureres, grocery-store owners and consumers do not know if the food has been unduly exposed to higher temeperatures, which could cause unexpected spoliage, the tag still gives a reliable indication of the quality of the product."


How Do The Tags Work?


Food Tag: Source: Food Quality News. comFood Tag: Source: Food Quality News. com


About the size of a kernel of corn, the tag changes color from red (100% fresh) to green (100% spoiled) with orange and yellow in between.  if a label claims the product is good for 30 days, for example, and the tag is orange, that immediately tells the consumer that the produc tis good for another 15 days. The tags are comprised of  non-toxic metals (silver and gold nanorods) that cost less than one cent ($0.002) a piece to produce.

The E.coli bacteria found in milk was used as a reference model and the National Natural Science Foundation of China, Hong Kong Research Grants Council and National Basic Research Program of China sponsored the original study. In Zhang's own words:"We successfully synchronized, at multiple temperatures, the chemical evolution process in the smart tag with microbial growth processes in the milk."

The tags are versatile and can be customized for many foods and beverages. The next step in the process is to market the tags to grocery store owners and food manufacturers since their advantages fall within the purview of this industry as well as consumers. The tags serve as highly visible wathcdogs and although they don't bark, they are a reliable indication of the freshness factor of any canned or dairy product.

 What Makes The Tags Turn Color?

The process is pure alchemy. The tags contain silver chloride and vitamin C. According to Zhang:

"Silver chloride and vitamin C are also in the tags, reacting slowly and controllably. Over time, the metallic silver  gradually deposits on each gold nanorod, forming a silver shell layer. That changes the particle's chemical composition and shape. As tthe silver rlayer thickens over time, the tag color evolves from the inital red to orange, yellow and green and even blue and violet."

 Food Waste Infographic: Source: Daily Concepts.comFood Waste Infographic: Source: Daily


Will these food deterioration tags revolutiize the waste aspect within the  food industry?

Perhaps only time  will tell as every new product under the sun must go through its own marketing and acceptance phases. It seems evident, however, that these tags can only be as Martha Stewart always says, "a goofd thing."