Fraunhofer Institute researchers have developed an antimicrobial active-packaging film that destroys microorganisms on the product surface to increase shelf life of products like fresh meat, fish, cheese, and cold cuts. Carolin Hauser, a food chemist at the Fraunhofer Institute for Process Engineering and Packaging IVV in Freising, developed and tested a new, lacquer-based antimicrobial active film that incorporates a controlled release mechanism.

Fraunhofer notes that although freshly slaughtered fish and meat is virtually sterile it becomes contaminated during processing and packaging, with around 20 different species of bacteria, yeasts, and molds serving to discolor the product over time and create bad odors.

With Hauser's technology, an antimicrobial agent is released onto the product surface on direct contact. EU Regulation 450/2009 allows companies to use antimicrobial materials to extend the shelf life of packaged foods, and goes as far as to permit the incorporation of components that are specifically designed to release substances into or onto the food in question. Fraunhofer notes that this kind of packaging has already been introduced in Japan, where silver, wasabi, and ethanol are among the active ingredients deployed in packaging.

The active agents must not be poisonous or allergenic, and also must be neutral in terms of smell and taste. Furthermore, Fraunhofer says any active agent must be readily transferrable onto packaging film. Given this, Hauser elected to use sorbic acid, which she dissolved in a lacquer and deposited on a base film.

Hauser tested the film on several pieces of pork loin. A day after slaughter, she contaminated each of the loins with approximately 1000 colony-forming units of the E. coli pathogen, wrapping some of the meat in standard film as a control, with the rest stored in active film. After seven days in a refrigerator at 8ºC, Hauser noted clear differences in color. An microbial examination revealed that the active packaging had successfully destroyed many of the germs on the actively packed meat, with the number of E. coli on those pieces cut to a quarter of their original level. —[email protected]