System feasibility: Designing a chlorine dioxide self-generating package label to improve fresh produce safety part I: Extrusion approach

Abstract

Abstract There is need for in-package anti-microbial technology to control microbial growth on packaged fresh food. This research evaluated the feasibility of delivering chlorine dioxide (ClO 2 ) via package labels made of synthetic polymers extruded with citric acid (CA) and sprayed with sodium chlorite. Heat pressing facilitated ClO 2 generation and moisture triggered ClO 2 release. Of three synthetic polymers tested, only ethylene vinyl acetate (EVA) label withstood extrusion and storage conditions without structural changes. EVA labels containing 15 or 7.5% CA generated 3.2–4.2 and 0.5–1.0 mg ClO 2 /L air, respectively. Total inactivation of Salmonella cells on TSA plates (2.13 log CFU/plate) was achieved following exposure to 15% CA labels for 2 h; 7.5% CA labels gave partial inactivation (1.03 log CFU/plate) following up to 6 h of exposure. Our findings demonstrate: 1) the practical feasibility of this synthetic package label design; 2) ClO 2 generation and release following activation; and 3) antimicrobial effectiveness against Salmonella growth. Industrial relevance Feasibility for synthesizing a package label to generate and deliver chlorine dioxide (ClO 2 ) as an effective antimicrobial inside individual food packages has been demonstrated. The approach extrudes polymers with citric acid, then sprays the surface with sodium chlorite. Heat pressing the label just before application initiates reaction between these two agents to generate ClO 2 . Release of ClO 2 is stimulated and maintained by moisture in the film and emanating from fresh foods.