Growth and reproduction of gram‐negative bacteria has a pivotal role in spoilage of seafood products. In order to identify the effect of lactoperoxidase system (LPOS), an antimicrobial activity was added to whey protein solution at the levels of 0 (control group), 1.25%, 2.5%, 5%, and 7.5%. Then, the shrimp samples were coated with immersion method and stored in the refrigerator for 16 days. In this period, the microbial tests of psychrotrophic bacteria, mesophilic bacteria, Pseudomonas fluorescens, Pseudomonas spp., and Shewanella putrefaciens , chemical tests of total volatile basic nitrogen, thiobarbituric acid, and pH, and sensory evaluation were carried out on the days of 0, 4, 8, 12, and 16. Adding LPOS in the coating resulted in a decrease in the total specific spoilage organisms and TVB‐N. There was no significant effect for the TBA test. The levels of LPOS showed a positive correlation with the acceptable measurement in the sensory evaluation.