Subzero saline chilling with or without prechilling in icy water improved chilling efficiency and meat tenderness of broiler carcasses

Freshly slaughtered carcasses need to be chilled to improve product quality, meat safety, and processing efficiency. This research investigated the effect of subzero saline chilling (SSC) on broiler carcasses with or without prechilling in icy water. Water immersion chilling at 0.5°C (WIC) or SSC at 4% NaCl/−2.41°C (SSC) was a major chilling step. For the combination of pre- and postchilling, the warm water immersion chilling (WWIC) at 10°C was used as prechilling and the WIC as postchilling (WWIC-WIC), and WIC was used as prechilling and the SSC as postchilling (WIC-SSC). The internal temperature of breast fillets was monitored during chilling. Carcasses in a prechiller were transported to a postchiller when their internal temperature reached 15°C. Chilling was completed when the carcass temperature reached 4.4°C or below, and breast fillets were harvested at 3-h postmortem to measure the pH and sarcomere length. Color (L*, a*, and b*) values were evaluated on both breast skin and skinless breast surfaces. Meat tenderness was evaluated using the breast fillets after overnight storage and cooking to an internal temperature of 76°C. The carcasses in the SSC and WIC-SSC showed shorter chilling times (85–91 min) than those (100–144 min) of WIC and WWIC-WIC. A higher chilling yield was observed for the carcasses in WIC-SSC, and a lower cooking yield was seen for the carcasses in WWIC-WIC than other chilling methods (P < 0.05). The breast fillets of broilers in the SSC and WIC-SSC showed lower shear forces and longer sarcomere length than the WIC and WWIC-WIC. No difference was found for L* and a* values, while lower b* value was observed in the SSC than the other chilling methods (P < 0.05). Based on these results, chilling of broiler carcasses in the SSC (4% NaCl/−2.41°C) with or without prechilling in WIC at 0.5°C significantly improved chilling efficiency and meat tenderness, with minor color changes on carcasses.