Effects of incorporating calcined corals as natural antimicrobial agent into active packaging system for milk storage

A series of nylon (NY)/linear low-density polyethylene (LLDPE) containing calcined corals (NY/LL-CORALS) composite films were prepared using the cast extrusion method. We investigated the effect of different contents of incorporated calcined corals on the physical properties and antimicrobial activity of the composite films as well as their feasibility for milk storage applications. The results indicated that the main compound in calcined corals was calcium oxide (CaO). As the calcined corals content increased, the crystallinity of the composite films slightly decreased, but no significant changes in their thermal stability and permeability were observed. The NY/LL-CORALS composite films exhibited excellent antimicrobial performance against Escherichia coli and Staphylococcus aureus. Notably, the NY/LL-CORALS packaging significantly extended the lag time of bacteria and delayed the bacterial growth cycle in milk during storage. Thus, the NY/LL-CORALS composite films could be a potential food packaging material that could prolong the shelf life of fresh food.