Although the application of silver based antimicrobial systems is a widespread technology, its implementation in
areas such as food packaging is still challenging. The present paper describes the fabrication of poly(lactic acid)
(PLA) coated with beeswax with controlled release properties for sustained antimicrobial performance. Release
of silver ions from the polymers was monitored voltammetric under various conditions (surface contact,
immersion in various liquid media and at different pH values) throughout at least 7 days. A higher release was
noted with decreasing pH while surface release was much slower than the release when immersed in liquid
medium. While uncoated films demonstrated a high burst release which in some instances implied surpassing
some current migration restrictions (b0.05 mg/kg food), the addition of a beeswax layer allowed a sustained
release of the antimicrobial compound. Increasing the thickness of the beeswax layer resulted in an increase in
the water barrier properties of the films while reducing the relatively constant values of sustained release.
Antimicrobial performance was correlated with the release of silver ions, indicating threshold concentrations
for biocide action of b6 μg/L and 9–14 μg/L for surface contact and in liquid media, respectively. Either by surface
contact or by immersion in growth medium or vegetable soup, the coated films displayed a strong bactericidal
effect against Salmonella enteric. The application of this functional barrier thus offers the possibility of tuning
the release profiles of the films to suit a specific application and puts forth the possible suitability of these
materials for food packaging or other migration sensitive applications.