Shelf-Life Extension of Refrigerated Pork Nuggets by Active Tray Packaging in Polypropylene Trays with Different Barrier Wrap Films and an Iron-Based Oxygen Scavenger

Abstract

Pork nuggets are an emulsion-based, cooked, ready-to-eat meat product whose lipid- and protein-rich matrix is highly susceptible to  oxidative deterioration and post-process microbial recontamination during chilled retail. The present study evaluated the effect of four  food-grade wrap films (LDPE, LLDPE, HDPE and PVC) combined with food-grade polypropylene trays, with or without an iron-based  oxygen scavenger sachet (2.5 g O-SORB U100), on the physico-chemical, microbiological and sensory quality of refrigerated pork  nuggets. Pork nuggets prepared from a standardised emulsion (70% lean meat, 10% vegetable oil, 10% ice, 3.5% onion-garlic, 2.5% corn  flour and curing salts) were heat-processed to a core temperature of ≥82 °C, sliced (13 mm) and tray-packaged (200 g per tray). Eight  treatments were stored at 4 ± 1 °C for up to 23 days and sampled on days 0, 5, 10, 13, 16, 19, 21 and 23. Pork nuggets tray-packaged with  HDPE wrap and an in-pack oxygen scavenger (THDPE) retained acceptable quality up to 23 days, whereas the same product wrapped  in HDPE without scavenger or in LDPE, LLDPE or PVC with scavenger remained acceptable only up to 21 days, and pork nuggets in  control LDPE, LLDPE or PVC packs (no scavenger) spoiled by day 19. On day 19, THDPE recorded the lowest values of TBARS (0.403 mg  MDA/kg), free fatty acid value (0.464% oleic acid), tyrosine value (0.601 mg/g), total plate count (3.58 log CFU/g), and highest sensory  acceptance, in comparison with CLDPE (TBARS 0.480 mg MDA/kg, FFA 0.683%, tyrosine 0.704 mg/g, TPC 4.03 log CFU/g). The HDPE +  oxygen scavenger system therefore extended the refrigerated shelf-life of pork nuggets by 4 days (from 19 to 23 days) relative to current  LDPE retail practice and represents a practical, cost-effective tray-packaging upgrade for chilled processed-pork retailing.