The shelf life of grade-A pasteurized milk has increased from 7 days to 15 days with an innovative packaging solution by Agrindus, an agribusiness company located in Sao Carlos, Brazil, as per phys.org. This was achieved by incorporating silver-based nanoparticles 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 Sao 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 Sao 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 Simoes. According to Simoes, 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," Simoes said.
In addition to Agrindus, the material is also being tested by two other dairies that distribute fresh milk in plastic bottles in Sao 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 4-10 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℃ to 150℃ 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," Simoes said, adding, "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."
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.
Completed in April 2016, the BIO4MAP project is now bringing a new type of sustainable food packaging to the market. The consortium promises a significant increase in shelf life for fresh pasta and cheese, a cost 25% lower than alternatives, and an environmental and carbon footprint reduced by up to 29%. The newly developed packaging material consists at least 75% of raw materials from renewable sources. It includes different layers of bioplastics - PLA, PVOH and adhesives - and a wax coating produced from olive leaves. It is easy to recycle, presents excellent mechanical properties, is biodegradable and protects its content from oxygen and humidity, thereby preventing the development of bacteria and fungi. The project, which had a budget of EUR 1.5 million, was coordinated by AIMPLAS - a research technology centre located in Spain with 25 years of experience in plastics research and development. 'The role of AIMPLAS in this project, besides coordinating it, has been focused on developing the biodegradable and oxygen-barrier material needed to comply with the final requirements of the food to be packaged, as well as being the responsible of processing the new materials developed to obtain the new multilayer packaging,' Nuria Lopez, main Researcher at AIMPLAS, explained.
Brought together, the materials contained in the BIO4MAP's packaging have a carbon footprint that is 57% lower than that of materials traditionally use to pack cheese and fresh pasta. PLA boasts excellent mechanical properties and ease of recycling, whilst PVOH is a good gas barrier with water solubility: it disappears in the washing process, allowing PLA to be properly isolated and recycled. A wax coating processed by project partner Fraunhofer covers the external layer of the packaging, providing water vapour barrier and improving the flexibility of PLA. All these materials are joined by a new generation of biodegradable adhesives, which is one of the main innovations brought by BIO4MAP. While these materials were already commercially available, their processing as a co-extrudate into a multilayer laminate had yet to be achieved.