Food grade antimicrobial delivery systems were studied in this work to enhance the effectiveness of antimicrobials inhibiting the growth of Listeria monocytogenes during storage. Corn zein was used as a carrier biopolymer and nisin and thymol as antimicrobials. Capsules produced by spray drying demonstrated different microstructures and release characteristics of nisin at different usage levels of thymol. Better release profiles were achieved when glycerol was additionally used to prepare capsules. Capsules showing sustained release of significant amounts of both antimicrobials effectively inhibited the growth of L. monocytogenes at pH 6.0 and 30 °C in the growth medium. Capsules were also more effective than free antimicrobials in inhibiting the growth of L. monocytogenes in 2% reduced fat milk at 25 °C. Our work showed that engineered delivery systems have promise to fulfill the antimicrobial effectiveness during shelf life storage of foods to ensure microbiological safety.