Researchers in Chile have invented a system incorporating natural microbial agents in a polymeric structure aimed at increasing the shelf life of refrigerated fresh salmon.
Abel Guarda said it could offer shelf life increases of up to four days depending on storage temperature. The application was made by Guarda, Ximena Valenzuela, Alberto Ramirez and Jose Maria Galotto from the Universidad de Santiago de Chile to the European Patent Office.
The first step to produce the active packaging material is described in the application as mixing a first extrusion of the antimicrobial active agent thymol with low density polyethylene powder to obtain a pellet. The next step is a second extrusion to obtain a film incorporating the pellet obtained in step one in a proportion of 10% polyethylene pellets. The last step is a three-layer coextrusion to develop the film into which the antimicrobial agent is incorporated.
Animicrobial effectiveness was measured with E.coli
, where a reduction of 100% was shown after 24 hours providing the concentration of microbial in the films was more than 10%. Reduction of Listeria
at 24 hours was more than 99% with a final effective concentration in the film of only 0.46%.
A chemical analysis compared the results between the active packaging and a control and showed that the active packaging material offers a difference of four days in the shelf life of packed salmon.
Source: Universidad de Santiago de Chile