Antimicrobial packaging based on E-polylysine bioactive film for the control of mycotoxigenic fungi in vitro and in bread

E-Poly-L-lysine (E-PL) is a cationic peptide with a broad-spectrum antimicrobial activity. This study
investigates the use of E-PL as natural antimicrobial to inhibit fungal growth and to reduce aflatoxins
(AFs) production. Antifungal activity of starch biofilms with different concentrations of E-Poly-
L-lysine (E-PL) was determined in solid medium against Aspergillus parasiticus (AFs producer) and
Penicillium expansum. Then, biofilms were tested as antimicrobial devices for the preservation of
bread loaf inoculated with A. parasiticus CECT 2681 and P. expansum CECT 2278. Shelf life and
AFs content were examined. Biofilms with concentrations of E-PL less than 1.6 mg/cm2 showed
no fungal growth inhibition in solid medium, while the antifungal activity of the films with greater
than 1.6 mg/cm2 of E-PL was dose dependent. The shelf life of bread inoculated with A. parasiticus
was increased by 1 day with the use of films containing 1.6–6.5 mg E-PL/cm2, while shelf life of
bread tainted with P. expansum was increased by 3 day with 6.5 mg E-PL/cm2. AFs production
was greatly inhibited by E-PL biofilms (93–100%). Thus, E-PL biofilms could be potentially used as
antimicrobial device during bread storage as a natural alternative to the synthetic preservatives.