Mechanical and anti-pathogenic characterization of starch-based materials

Food products are susceptible to the growth of pathogenic microbes, such as Escherichia coli. Smart packaging is an effective non-invasive route to reducing food pathogens. Some lactic acid bacteria such as Lactobacillus plantarum inhibit the growth of pathogens. We report here the incorporation of L. plantarum within a starch matrix using sucrose as a protectant and glycerol as a plasticizer. The anti-pathogenic and mechanical characteristics of the films produced were tested. The properties of the films varied depending on their composition, with tensile strengths ranging from 6.8 - 8.7 MPa and maximum tensile stress relaxation from 4 - 13%. Antimicrobial activity (agar disk diffusion) assays showed that films incorporating L. plantarum inhibited E. coli moderately, and when assisted with starch-degrading α-amylase, E. coli growth was reduced significantly. These findings demonstrate the potential of this natural anti-pathogenic film to be applied as an edible coating for food and as a second layer with traditional synthetic thermoplastics to improve food shelf-life.