Tag Archives: milk

Brazilian company encapsulates silver nanoparticles in milk packaging for longer product life

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They’ve managed to double the shelf life for fresh milk from seven days to 15 be encapsulating silver nanoparticles in ceramic microparticles in packaging for fresh milk. From an Aug. 4, 2015 news item on Nanowerk,

Agrindus, an agribusiness company located in São Carlos, São Paulo state, Brazil, has increased the shelf life of grade A pasteurized fresh whole milk from seven to 15 days.

This feat was achieved by incorporating silver-based microparticles with bactericidal, antimicrobial and self-sterilizing properties into the rigid plastic bottles used as packaging for the milk.

The technology was developed by Nanox, also located in São Carlos. Supported by FAPESP’s Innovative Research in Small Business (PIPE) program, the nanotechnology company is a spinoff from the Center for Research and Development of Functional Materials (CDFM), one of the Research, Innovation and Dissemination Centers (RIDCs) supported by São Paulo Research Foundation (FAPESP).

“We already knew use of our antimicrobial and bactericidal material in rigid or flexible plastic food packaging improves conservation and extends shelf life. So we decided to test it in the polyethylene used to bottle grade A fresh milk in Brazil. The result was that we more than doubled the product’s shelf life solely by adding the material to the packaging, without mixing any additives with the milk”, said the Nanox CEO, Luiz Pagotto Simões.

An Aug. 4, 2015 Fundação de Amparo à Pesquisa do Estado de São Paulo news release on EurekAlert, which originated the news item, expands on the theme,

According to Simões, the microparticles are included as a powder in the polyethylene preform that is used to make plastic bottles by blow or injection molding. The microparticles are inert, so there is no risk of their detaching from the packaging and coming into contact with the milk.

Tests of the material’s effectiveness in extending the shelf life of fresh milk were performed for a year by Agrindus, Nanox and independent laboratories. “Only after shelf life extension had been certified did we decide to bring the material to market,” Simões said.

In addition to Agrindus, the material is also being tested by two other dairies that distribute fresh milk in plastic bottles in São Paulo and Minas Gerais and by dairies in the Brazilian southern region that sell fresh milk in flexible plastic packaging.

“In milk bags, the material is capable of extending shelf life from four to ten days,” he said.

Nanox plans to market the product in Europe and the United States, where much larger volumes of fresh milk are consumed than in Brazil.

The kind of milk most consumed in Brazil is ultra-high temperature (UHT), or “long life” milk, which is sterilized at temperatures ranging from 130°C to 150°C for two to four seconds to kill most of the bacterial spores. Unopened UHT milk has a shelf life of up to four months at room temperature.

Whole milk, known as grade A in Brazil, is pasteurized at much lower temperatures by the farmer and requires refrigeration. “Doubling the shelf life of whole milk translates into significant benefits in terms of logistics, storage, quality and food safety,” Simões said.

Countless applications

The silver-based microparticles developed by Nanox are currently being used in several other products other than packaging for fresh milk, including plastic utensils, PVC film for wrapping food, toilet seats, shoe insoles, hair dryers and flatirons, paints, resins, and ceramics, as well as coatings for medical and dental instruments such as grippers, drills and scalpels.

But the company’s largest markets today are makers of rugs, carpets, and white goods, such as refrigerators, drinking fountains and air conditioners.

“We’ve supplied several products to white goods manufacturers since 2007,” Simões said. “This material is shipped to the leading players in the market.” Nanox currently exports the product to 12 countries via local distributors in Chile, China, Colombia, Italy, Mexico and Japan, among others.

The company now wants to enter the United States, having won approval in 2013 from the Food & Drug Administration (FDA) to market the bactericidal material for use in food packaging.

“We’ve applied for clearance by the EPA [the Environmental Protection Agency] so that we can sell to a larger proportion of the US market,” Simões said.

Neither Brazil nor the US has clear legislation on the use of particles at the nanometer scale [a billionth of a meter] in products that involve contact with food, so the company uses nanotechnology processes that result in silver-based particles at the micrometer scale [a millionth of a meter], he said.

The core of the technology consists of coating ceramic particles made of silica with silver nanoparticles. The silver nanoparticles bond with the ceramic matrix to form a micrometre scale composite with bactericidal properties.

“The combination of silver particles with a ceramic matrix produces synergistic effects. Silver has bactericidal properties, and while silica doesn’t, it boosts those of the silver and helps control the release of silver particles to kill bacteria,” he said.

I wonder if they’ve done any ‘life cycle’ analysis. In other words, what happens to the packaging and those encapsulated silver nanoparticles when the milk jugs (and Nanox’s other silver-based products) are recycled or put in the garbage dump?

You can find out more about Nanox (English language version) here and about Agrindus, a division of Letti?, (you will need Portuguese language reading skills) here.

Invisibility cloak effective in fog and milk

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It’s an intriguing notion, an invisibility cloak that’s effective in milk and I suspect that I’ve never entirely understood the implications of the research featured in a June 6, 2014 news item on Nanowerk,

Real invisibility cloaks are rather complex and work in certain situations only. The laws of physics prevent an optical invisibility cloak from making objects in air invisible for any directions, colors, and polarizations. If the medium is changed, however, it becomes much easier to hide objects. KIT physicists have now succeeded in manufacturing with relatively simple means and testing an ideal invisibility cloak for diffusive light-scattering media, such as fog or milk. …

A June 6, 2014 Karlsruhe Institute of Technology (KIT) press release, which originated the news item, provides more details,

In diffusive media, light does no longer propagate linearly, but is scattered permanently by the particles in the medium. Examples are fog, clouds, or frosted glass panes that let the light in, but hide the light source. “This property of light-scattering media can be used to hide objects inside,” says Robert Schittny, first author of the study. “The new invisibility cloaks have a rather simple structure.”

In the experiment, Schittny used an extended light source to illuminate a Plexiglas tank of a few centimeters in width from the back. The tank was filled with a white, turbid liquid. Objects inside cast a visible shadow onto the tank wall. Simple metal cylinders or spheres of a few centimeters in diameter were used as test objects. To hide them, they were first coated with a white dispersion paint, such that the light was reflected in a diffusive manner. To pass the light around the object, the researchers applied a thin shell made of the transparent silicon material PDMS, to which a certain concentration of light-scattering melamine microparticles was added. The silicon/melamine shell caused a quicker diffusion than in the environment and, thus, passed the light around the objects. Hence, they did no longer cast a shadow. “Disappearance of the shadow indicates successful cloaking.”

“Ideal optical invisibility cloaks in air have a drawback,” Martin Wegener points out. He conducts research at the KIT Institute of Applied Physics and the KIT Institute of Nanotechnology. “They violate Albert Einstein’s theory of relativity that prescribes an upper limit for the speed of light. “In diffuse media, in which light is scattered several times, however, the effective speed of light is reduced. Here, ideal invisibility cloaks can be realized.”

The researchers have provided this image to illustrate their work,

In a diffusive light-scattering medium, light moves on random paths (see magnifying glass). A normal object (left) casts a shadow, an object with an invisibility cloak (right) does not. (Image: R. Schittny / KIT)

In a diffusive light-scattering medium, light moves on random paths (see magnifying glass). A normal object (left) casts a shadow, an object with an invisibility cloak (right) does not. (Image: R. Schittny / KIT)

I’m not convinced that there’s actually a cloaked object in that image but I appreciate the call to use my imagination.

Here’s a link to and a citation for the paper,

Invisibility cloaking in a diffusive light scattering medium by Robert Schittny, Muamer Kadic, Tiemo Bückmann, and Martin Wegener. Science DOI: 10.1126/science.1254524 Published Online June 5 2014

This article is behind a paywall.

Blood-, milk-, and mucus-powered electronics

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Researchers at Tel Aviv University ([TAU] Israel) have already begun to develop biodegradable display screens in their quest to create electronic devices powered by blood, milk, and mucus proteins found in our bodies. From the March 7, 2012 news item on Nanowerk,

… a team including Ph.D. students Elad Mentovich and Netta Hendler of TAU’s Department of Chemistry and The Center for Nanoscience and Nanotechnology, with supervisor Dr. Shachar Richter and in collaboration with Prof. Michael Gozin and his Ph.D. student Bogdan Belgorodsky, has brought together cutting-edge techniques from multiple fields of science to create protein-based transistors — semi-conductors used to power electronic devices — from organic materials found in the human body. They could become the basis of a new generation of nano-sized technologies that are both flexible and biodegradable.

The March 7, 2012 news release on the American Friend of TAU website notes some of the issues with silicon-based electronics,

One of the challenges of using silicon as a semi-conductor is that a transistor must be created with a “top down” approach. Manufacturers start with a sheet of silicon and carve it into the shape that is needed, like carving a sculpture out of a rock. This method limits the capabilities of transistors when it comes to factors such as size and flexibility.

The TAU researchers turned to biology and chemistry for a different approach to building the ideal transistor. When they applied various combinations of blood, milk, and mucus proteins to any base material, the molecules self-assembled to create a semi-conducting film on a nano-scale. In the case of blood protein, for example, the film is approximately four nanometers high. The current technology in use now is 18 nanometers, says Mentovich.

Together, the three different kinds of proteins create a complete circuit with electronic and optical capabilities, each bringing something unique to the table. Blood protein has the ability to absorb oxygen, Mentovich says, which permits the “doping” of semi-conductors with specific chemicals in order to create specific technological properties. Milk proteins, known for their strength in difficult environments, form the fibers which are the building blocks of the transistors, while the mucosal proteins have the ability to keep red, green and, blue fluorescent dyes separate, together creating the white light emission that is necessary for advanced optics.

Overall, the natural abilities of each protein give the researchers “unique control” over the resulting organic transistor, allowing adjustments for conductivity, memory storage, and fluorescence among other characteristics.

I have previously featured work on vampire (blood-powered) fuel cells and batteries  in my July 18, 2012 posting and my April 3, 2009 posting so the notion of using blood (and presumably other bodily fluids) as a source for electrical power is generating (pun intended, weak though it is) interest in many research labs.

While the researchers don’t speculate about integrating these new carbon-based devices, which are smaller and more flexible than current devices, in bodies (from the American Friends of TAU news release),

Technology is now shifting from a silicon era to a carbon era, notes Mentovich, and this new type of transistor could play a big role. Transistors built from these proteins will be ideal for smaller, flexible devices that are made out of plastic rather than silicon, which exists in wafer form that would shatter like glass if bent. The breakthrough could lead to a new range of flexible technologies, such as screens, cell phones and tablets, biosensors, and microprocessor chips.

Just as significant, because the researchers are using natural proteins to build their transistor, the products they create will be biodegradable. It’s a far more environmentally friendly technology that addresses the growing problem of electronic waste, which is overflowing landfills worldwide.

The biodegradability of these proposed devices may be a problem if they are integrated into our bodies but it is certain that this will be attempted as we continue to explore machine/flesh possibilities.