The effectiveness of the chitosan-EAC may be due to the positive charge developed by chitosan in acidic medium (pH < 5.5). Protonation of an amino group present on each glucosamine unit makes it soluble in an aqueous medium and confers greater antimicrobial activity (Perdones and others 2012). Moreover, the nondissociated forms of sodium benzoate and potassium sorbate have antimicrobial activities, which increase with decreasing pH (the optimum effectiveness is pH 2.5 to 4.0). The coating forming solution based on chitosan and pectin were pH 4.00 and 4.10, respectively (data not shown), which may explain their abilities to reduce overall microbial growth. The coating forming solution based on pullulan was pH 6.68 (data not shown), and, therefore, it was less effective at reducing microbial growth in general.