Jack Kenny03.21.16
This morning I went shopping for groceries. The sell-by date on the milk is five days from now. Both the package of cookies and the container of V8 juice are stamped October 2016, letting me know that each has enough chemistry to keep them “fresh” until the leaves fall to the lawn (and it’s still winter). The beer says “Canned on 12/02/15.” If I didn’t know much about beer and its shelf life I wouldn’t know how long this one would remain drinkable.
The parmigiano reggiano cheese doesn’t have any kind of a sell-by, packaged-on or freshness date. It says it’s been aged already for 24 months, so it will be fine for a few more. But the fresh strawberries and oranges don’t have any such info either, and they surely don’t last too long.
Inventors and packaging specialists have been at work for years trying to come up with successful methods of informing consumers of the freshness of perishable products – or at the least, to inform them when a product has passed its recommended window of consumption. I live well within the great circle of influence of New York City, where one would think such inventions would be visible and available. Haven’t seen one yet.
More than a decade ago, a New Zealand converter named Jenkins Group, working with a science tank called HortResearch, came up with a fruit freshness detector, a label that functions as an intelligent sensor, causing a printed dot on the substrate to change color as the fruit ripens. Known as ripeSense, it is red when the fruit is young, then changes to orange and finally to yellow as it reaches maturity. It works by reacting to the gases produced by the fruits, and changes color when the composition of those gases is altered by age.
Jenkins, a major supplier to New Zealand’s horticultural industry, is still producing ripeSense, but perhaps its use is limited to certain regions of the world.
We’ve all seen and known about time-temperature indicators for years, but their use in the food industry at retail has been limited, probably because of cost factors. A couple of years ago, however, a team from Peking University in Beijing unveiled a tag for food containers that changed color with the passage of time along with changes in temperature.
Time-temperature indicators work by tracking a product’s exposure to extreme temperatures and the amount of time at that temperature. The researchers from China say that their color-changing tag would be much cheaper than previous devices and can be programmed for different foods.
When the food is fresh the tag is red. As time goes by, the tag passes through orange and yellow to green to indicate declining stages of freshness. The final color, bright green, means the product is no longer fresh. Preliminary research results were published in ACS Nano.
The tags are made of silver and gold nanorods and other chemicals, including chloride and vitamin C. “The metallic silver gradually deposits on each gold nanorod, forming a silver shell layer,” says Chao Zhang, the lead author of the study. “That changes its chemical composition and shape, so the tag color now would be different. Therefore, as the silver layer thickens over time, the tag color evolves from the initial red to orange, yellow, and green, and even blue and violet.”
The laboratories are busy. Less than two years ago, five scientists at Kasetsart University in Bangkok developed a food spoilage indicator for monitoring the freshness of skinless chicken breasts. The on-package indicator used color-change technology to measure the migration of carbon dioxide out of the chicken, because the CO2 increases as the chicken piece gets older. Around the same time, a study was published by three Korean scientists who developed a spoilage indicator for fish. There’s no word yet whether the inventions have been commercialized.
Bump Mark
A clever tool for detecting freshness and spoilage in food products – still in the exploration phase – is a little tag called Bump Mark, developed by Solveiga Pakstaite, a recent graduate of Brunel University in the UK. An energetic industrial designer, Pakstaite has already delivered a TED talk and promotes her work at Design by Sol.
In the course of conducting research into how blind people utilize public transportation, Pakstaite became aware of the difficulties that sightless people have when shopping for food. Without sight they have less ability than those who see to determine if a package’s contents appear to be fresh. She came up with a small tag that affixes to the corner of a package that will give freshness information to consumers, blind or otherwise, by use of a simple tactile process.
Bump Mark is a four-layer construction: The top is plastic film, under which lies a layer of gelatin; below the gelatin is a plastic sheet with raised bumps; the bottom layer is plastic film with an adhesive below. When the food inside the package is fresh, the surface of the Bump Mark is smooth. But as freshness deteriorates, the finger can detect the embedded bumps, at first slightly and then more distinctly as the chemistry of the food goes south.
The gelatin is the key. The substance, made from the bones of animals, is a solid jelly when it sets, but turns to liquid when it ages. Gelatin mimics the reaction of the food in the package to changing temperatures. If it is kept in the cold it will remain solid for longer, but in warmer conditions it will deteriorate more quickly, as would a piece of meat. It is the transformation of the gelatin to a liquid that enables the consumer to detect the bumps on the embedded layer of the tag.
“The Bump Mark would be stuck onto the package at the same time as the food is at its freshest and this basically starts decaying at the same time,” Pakstaite said in an interview with The Guardian. “If you take it out of the fridge, the food starts expiring quicker obviously because of the higher temperature, and the gelatin is going to start expiring quicker as well. I have basically taken another food to tell you what is happening to the food inside the package. It is just that this type of food [gelatin] has the unique property of changing states, and gelatin has this property of when it completely expires, it releases its bonds because all of the bacteria has eaten those bonds and it turns back into a liquid. So when you run your finger over the top, you can feel the bumps underneath. It is really simple – it is a sandwich which breaks down and reveals the bumps underneath.”
The Bump Mark would be applied at the time the food is packaged. If crates of the food were exposed for a period of time to warm, non-refrigerated air, the changes in the food would be mirrored by changes in the gelatin. With the Bump Mark, “the store will have to be completely diligent and regimented and honest.”
Early market research has taught Pakstaite that some vegetarians would not look favorably on Bump Mark because it makes use of an animal byproduct. Alternatives would be to use a different compound in the tag or to limit its use to dairy and meat products.
The author is president of Jack Kenny Media, a communications firm specializing in the packaging industry, and is the former editor of L&NW. He can be reached at jackjkenny@gmail.com.
The parmigiano reggiano cheese doesn’t have any kind of a sell-by, packaged-on or freshness date. It says it’s been aged already for 24 months, so it will be fine for a few more. But the fresh strawberries and oranges don’t have any such info either, and they surely don’t last too long.
Inventors and packaging specialists have been at work for years trying to come up with successful methods of informing consumers of the freshness of perishable products – or at the least, to inform them when a product has passed its recommended window of consumption. I live well within the great circle of influence of New York City, where one would think such inventions would be visible and available. Haven’t seen one yet.
More than a decade ago, a New Zealand converter named Jenkins Group, working with a science tank called HortResearch, came up with a fruit freshness detector, a label that functions as an intelligent sensor, causing a printed dot on the substrate to change color as the fruit ripens. Known as ripeSense, it is red when the fruit is young, then changes to orange and finally to yellow as it reaches maturity. It works by reacting to the gases produced by the fruits, and changes color when the composition of those gases is altered by age.
Jenkins, a major supplier to New Zealand’s horticultural industry, is still producing ripeSense, but perhaps its use is limited to certain regions of the world.
We’ve all seen and known about time-temperature indicators for years, but their use in the food industry at retail has been limited, probably because of cost factors. A couple of years ago, however, a team from Peking University in Beijing unveiled a tag for food containers that changed color with the passage of time along with changes in temperature.
Time-temperature indicators work by tracking a product’s exposure to extreme temperatures and the amount of time at that temperature. The researchers from China say that their color-changing tag would be much cheaper than previous devices and can be programmed for different foods.
When the food is fresh the tag is red. As time goes by, the tag passes through orange and yellow to green to indicate declining stages of freshness. The final color, bright green, means the product is no longer fresh. Preliminary research results were published in ACS Nano.
The tags are made of silver and gold nanorods and other chemicals, including chloride and vitamin C. “The metallic silver gradually deposits on each gold nanorod, forming a silver shell layer,” says Chao Zhang, the lead author of the study. “That changes its chemical composition and shape, so the tag color now would be different. Therefore, as the silver layer thickens over time, the tag color evolves from the initial red to orange, yellow, and green, and even blue and violet.”
The laboratories are busy. Less than two years ago, five scientists at Kasetsart University in Bangkok developed a food spoilage indicator for monitoring the freshness of skinless chicken breasts. The on-package indicator used color-change technology to measure the migration of carbon dioxide out of the chicken, because the CO2 increases as the chicken piece gets older. Around the same time, a study was published by three Korean scientists who developed a spoilage indicator for fish. There’s no word yet whether the inventions have been commercialized.
Bump Mark
A clever tool for detecting freshness and spoilage in food products – still in the exploration phase – is a little tag called Bump Mark, developed by Solveiga Pakstaite, a recent graduate of Brunel University in the UK. An energetic industrial designer, Pakstaite has already delivered a TED talk and promotes her work at Design by Sol.
In the course of conducting research into how blind people utilize public transportation, Pakstaite became aware of the difficulties that sightless people have when shopping for food. Without sight they have less ability than those who see to determine if a package’s contents appear to be fresh. She came up with a small tag that affixes to the corner of a package that will give freshness information to consumers, blind or otherwise, by use of a simple tactile process.
Bump Mark is a four-layer construction: The top is plastic film, under which lies a layer of gelatin; below the gelatin is a plastic sheet with raised bumps; the bottom layer is plastic film with an adhesive below. When the food inside the package is fresh, the surface of the Bump Mark is smooth. But as freshness deteriorates, the finger can detect the embedded bumps, at first slightly and then more distinctly as the chemistry of the food goes south.
The gelatin is the key. The substance, made from the bones of animals, is a solid jelly when it sets, but turns to liquid when it ages. Gelatin mimics the reaction of the food in the package to changing temperatures. If it is kept in the cold it will remain solid for longer, but in warmer conditions it will deteriorate more quickly, as would a piece of meat. It is the transformation of the gelatin to a liquid that enables the consumer to detect the bumps on the embedded layer of the tag.
“The Bump Mark would be stuck onto the package at the same time as the food is at its freshest and this basically starts decaying at the same time,” Pakstaite said in an interview with The Guardian. “If you take it out of the fridge, the food starts expiring quicker obviously because of the higher temperature, and the gelatin is going to start expiring quicker as well. I have basically taken another food to tell you what is happening to the food inside the package. It is just that this type of food [gelatin] has the unique property of changing states, and gelatin has this property of when it completely expires, it releases its bonds because all of the bacteria has eaten those bonds and it turns back into a liquid. So when you run your finger over the top, you can feel the bumps underneath. It is really simple – it is a sandwich which breaks down and reveals the bumps underneath.”
The Bump Mark would be applied at the time the food is packaged. If crates of the food were exposed for a period of time to warm, non-refrigerated air, the changes in the food would be mirrored by changes in the gelatin. With the Bump Mark, “the store will have to be completely diligent and regimented and honest.”
Early market research has taught Pakstaite that some vegetarians would not look favorably on Bump Mark because it makes use of an animal byproduct. Alternatives would be to use a different compound in the tag or to limit its use to dairy and meat products.
The author is president of Jack Kenny Media, a communications firm specializing in the packaging industry, and is the former editor of L&NW. He can be reached at jackjkenny@gmail.com.