PET and Active Coating Based on a LDH Nanofiller Hosting p-Hydroxybenzoate and Food-Grade Zeolites: Evaluation of Antimicrobial Activity of Packaging and Shelf Life of Red Meat.

Valeria Bugatti,Vittoria Vittoria,Luigi Vertuccio,Federica Zuppardi,Giuliana Gorrasi

doi:10.3390/nano9121727

Abstract

Layered double hydroxide (LDH) nanofillers were considered as hosts of p-hydroxybenzoate as an antimicrobial molecule for active coating. A food grade resin with LDH-p-hydroxybenzoate and two different types of food grade zeolites was used to prepare active coatings for Polyethylene terephthalate (PET) trays. The release kinetics of the active molecule were followed using UV spectrophotometry and the experimental results were analyzed with the Gallagher–Corrigan model. The thermal properties of the coating mixtures and the PET coating were analyzed and found to be dependent on the coating’s composition. On the basis of CO2 transmission rate and off-odors tests, the best coating composition was selected. Global migration in ethanol (10% v/v), acetic acid (3% w/v), and vegetable oil, and specific migration of p-hydroxybenzoic acid revealed the suitability of the material for food contact. Antimicrobial tests on the packaging demonstrated a good inhibition against Salmonella spp. and Campylobacter jejuni. Red meat was packed into the selected active materials and results were compared to uncoated PET packaging. Color tests (browning of the meat) and analysis of Enterobacteriaceae spp. and total viable count evolution up to 10 days of storage demonstrated the capability of the considered active packaging in prolonging the shelf life of red meat.

Highlights

Active packaging is a research area with important effects on the circular economy and consumer welfare
Layered double hydroxide (LDH) nanofillers were considered as hosts of p-hydroxybenzoate as an antimicrobial molecule for active coating
With antimicrobial activity for food products, can be divided into several categories: (i) volatile antimicrobial substances added into packaging, which are often enclosed separately in sachets or pads attached to the internal part of the package; (ii) antimicrobial agents incorporated into the bulk polymer; (iii) antimicrobials immobilized by ionic or covalent linkages to polymers; (iv) coating of polymer surfaces with antimicrobials; (v) use of polymers that are inherently antimicrobial [1,2,3]

Summary

Introduction

Active packaging is a research area with important effects on the circular economy and consumer welfare. The antimicrobial agent can be coated directly onto the film material before applying it to foods Another advantage over bulk incorporation is the fact that the incorporation of the active agent on the product contact side can minimize the amount used, and the cost of the active molecules required to impart efficacy to the system can be contained [4,5]. Poly(ethylene terephthalate) (PET) is one of the most used engineering polymers worldwide; around 50 million tons of PET are produced each year because of its applications, from packaging to fiber production In spite of this large use of PET in manufacturing, its consumptions in the last twenty years significantly increased over other alternative packaging materials (glass, aluminium, paper). The fresh meat’s shelf life was evaluated in terms of color change and inhibition against Enterobacteriaceae spp. and total viable count

Materials

Findings

Methods