Abstract: Highly hygroscopic pads with antibacterial activity were prepared by freeze-drying using a combination of chitosan, sodium carboxymethyl cellulose and montmorillonite as base material with different amounts of nisin added, and they were applied for the preservation of chilled pork. Grounded fresh pork was placed on each of the pads, which was located at the bottom of a plastic tray, and stored at 4 ℃. Total viable count (TVC), total volatile basic nitrogen (TVB-N) content, thiobarbituric acid reactive substances (TBARS) value, pH, cooking loss, hardness and color were examined every day. The results revealed that the application of the pads significantly inhibited microbial growth in meat, slowed down the increase in TVB-N content, TBARS value, and pH value, reduced cooking loss, and maintained the hardness and color of meat. The antimicrobial and antioxidant activities of the pads were improved by the combined use of chitosan and nisin, thus leading to better preservation of meat quality. By applying the nisin pad containing 0.5 g of nisin per kilogram of meat, the shelf life of fresh meat was extended to at least 4 days, which was twice longer than that of the control.

Key words: chitosan, nisin, hygroscopic pad, antibacterial, fresh pork, shelf life