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.
"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.
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.
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.
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.