Development of Antimicrobial Cellulose Nanofiber-Based Films Activated with Nisin for Food Packaging Applications.

The cellulose nanofiber (CNF) is characterized by the nano-sized (fibers with a diameter between 5 and 20 nm and a length between 2 and 10 μm), flexible and cross-linked structure that confer enhanced mechanical and gas barrier properties to cellulosic fiber-based packaging materials. The purpose of this work was to develop an antimicrobial packaging film by direct mixing nisin with CNF, followed by coating it onto polyethylene (PE), polypropylene (PP), and polylactic acid (PLA) films. The antimicrobial effectiveness of CNF-Nis+PE, CNF-Nis+PP, and CNF-Nis+PLA was investigated both in vitro end in ex vivo tests. In the latter case, challenge test experiments were carried out to investigate the antimicrobial activity of the coupled films of CNF-Nisin+PLA to inhibit the growth of 1770 during the storage of a meat product. The films were active against the indicator microorganisms and in in vitro test. Moreover, a reduction in the population of about 1.3 log cycles was observed immediately after the contact (T0) of the active films with hamburgers. Moreover, when the hamburgers were stored in active films, a further reduction of the population of about 1.4 log cycles was registered after 2 days of storage. After this time, even though an increase in load was observed, the trend of the population in hamburgers packed with active films was maintained significantly lower than the meat samples packed with control films during the whole storage period.