Bacteriostatic Polymers and Composites for the Construction of Active Packaging – BRICAPAC

Regarding both economic and environmental concerns, there is an increasing demand in recent years for fresh food products with an extended shelf life, i.e. an extent of the DLC (limit date for consumption). In this context, the present project, BRICAPAC focuses on the construction of active packaging with bacteriostatic properties to limit the development of spoilage and pathogenic bacteria in fresh food, while keeping a beneficial level of endogenous flora, required for the maturation of meat.

Therefore, BRICAPAC should both contribute to a better preservation of fresh products, an increase of DLC and a reduction of food waste.
This project relies on a complementary and solid consortium:
- two academic Laboratories (Paris-Saclay University): one expert in surface chemistry and polymer/composite science (Laboratory of Innovation in Surface Chemistry and Nanosciences at CEA/NIMBE) and the other specialized in microbiology and bioadhesive phenomena (Laboratory Bioadhesion, Biofilms and Hygiene of Materials at INRA/APT).
- two industrial partners: BOLLORE Plastic Film Division, specialized in the production of food films and european leader for barrier shrink films for fresh food, and CHARAL Innovation Pole, patent holder of the famous HebdoPack system (thermoformed film under vacuum) which ensures meat conservation more than 20 days.

The main component in food packaging is polyethylene (PE). So far, the introduction of bactericide species into polyethylene films has been performed through the adsorption of small molecules such as triclosan, nisin or essential oils. The problem resides in the release of these molecules out of the packaging, due to the simple physical adsorption onto the film and/or to the low thermal stability of the molecules towards high temperature of packaging process. The diffusion into the food could lead to a modification of the taste, or even worse to an alteration of the food quality. Other main strategies rely on the introduction of inorganic nanoparticles into the PE matrix. Some of them were based on the formation of a layer of silver nanocomposites directly onto the film via film-casting or the reduction of silver salt onto treated PE film. These antibacterial coatings have shown to be particularly efficient, but the release of silver ions from the composites could not be controlled. This is a problem for long term use and also regarding the toxicity of silver ions or NPs.

In BRICAPAC, to prevent any releasing effect, and regarding recent agreement for new food packaging additives, we will focus the present project in the use of active polymers. Indeed the use of polymers will bring several advantages: i) a higher amount of biocide groups; ii) a larger mobility (important parameter for interactions with bacteria membranes); iii) a better stability towards process conditions (temperature, stretching, etc.).

We will form a bacteriostatic polymer film (bioactive contact) where most undesirable bacteria will be trapped to limit their growth in order to prevent their multiplication on the product. To avoid any releasing phenomena, we will develop three industrializable strategies based on covalent grafting or cross-linking of these bacteriostatic polymers in the polyethylene structure.

Allowing access to fresh products with a higher DLC while maintaining nutritional qualities, taste and safety, is a strong selling argument. This will have an economic impact both directly for our industrial partners (CHARAL, BOLLORE), but also indirectly for other manufacturers of fresh food, which will use these active films marketed by BOLLORE. Moreover, the reduction of food waste via the increase of the DLC will also be a strong economic argument for the distribution chain of fresh food, especially regarding inventory managements.
BRICAPAC has recently been labelled by the "Pôle de Compétitivité" VITAGORA (food/agribusiness)