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.

Modified Atmosphere Packaging of Chicken Thigh Meat: Physicochemical and Sensory Characteristics during the Frozen Storage Period

This study aimed to explore the utilization of modified atmosphere packaging (MAP) for chicken thigh meat pieces (CTMP) during frozen storage periods (FSP) of 1, 30, 60, and 90 days at −18°C. The treatments were divided into seven groups which are control, vacuum, 15% O2/15% N2/70% CO2, 30% N2/70% CO2, 50% O2/50% N2, 30% O2/70% CO2, and 1.5 ml clove essential oil. The results showed that treatment of 30% N2/70% CO2 was associated with a lower pH value than control. The pH, drip loss, TBA, peroxide number, and fatty acid percentage values were significantly ( $p<0.05$ ) increased as FSP rises. The effect of the MAP and muscle fiber index (MFI) was significantly different ( $p<0.05$ ) by the FSP. A decrease in the drip loss during storage and cooking when samples were treated with a MAP of 15% O2/15% N2/70% CO2, 30% N2/70% CO2, and clove oil groups were noted. The lowest values of TBA, peroxide number, and fatty acid percentage were recorded using 15% O2/15% N2/70% CO2, 30% N2/70% CO2, and clove oil groups, respectively. There was an improvement in all sensory characteristics of all MAP and clove oil treatments.

Effects of hot water spray and sub-zero saline chilling on bacterial decontamination of broiler carcasses

Reduction of Salmonella on poultry carcasses is one way to prevent salmonellosis. The purpose of this research was to evaluate the effects of subzero saline chilling (SSC) with/without hot water spray (HWS) on broiler carcasses prior to chilling for bacterial reduction. Eviscerated broiler carcasses were subjected to water immersion chilling (WIC, 0% NaCl/0.5°C) or SSC (4% NaCl/-2.41°C) with/without prior HWS at 71°C for 1 min. Broiler carcasses in SSC were chilled faster than those in WIC, regardless of HWS. The combination of HWS and SSC resulted in the best reduction of mesophilic aerobic bacteria, Escherichia coli, and total coliforms on the carcasses over the WIC, SSC, and HWS/WIC. No Salmonella was detected on the carcasses in SSC and HWS/SSC while Salmonella positive was observed on the carcasses chilled in WIC and HWS/WIC. A trace of Gram-negative genus was detected on carcasses in HWS/SSC while many other microbiomes were observed on those in WIC, SSC, and HWS/WIC when quantitative microbiota profiles of 16S rRNA gene sequences were evaluated. Based on these results, chilling of broiler carcasses in 4% NaCl/-2.41°C after HWS at 71°C for 1 min significantly reduced carcass chilling time and bacterial contamination over the control chilling.

Research Note: Subzero saline chilling improved chilling efficiency and bacterial reduction of turkey carcasses

The poultry industry has attempted to improve carcass chilling efficiency, meat quality, and product safety. The purpose of this research was to investigate the effects of subzero saline chilling on carcass chilling time and microbial safety. Eviscerated tom turkeys were randomly picked from a local turkey processing plant and subjected to chilling in one of the 3 chilling solutions: 1) 0% NaCl/0.5°C (ice slurry control), 2) 4% NaCl/-2.41°C, and 3) 8% NaCl/-5.08°C. The turkey carcasses in subzero saline solutions were chilled more efficiently and reduced the chilling time over the carcasses in ice slurry solution. No significant difference was observed for carcass chilling yield and fillet cooking yield regardless of chilling method (P > 0.05). The number of mesophilic aerobic bacteria (MAB), Escherichia coli (E. coli), and total coliform cells were significantly reduced in the carcasses chilled in subzero saline solutions over the icy control, except MAB in 4% NaCl/-2.41°C (P < 0.05). Based on these results, the chilling of turkey carcass in subzero saline solution appears to improve carcass chilling efficiency and bacterial reduction, especially Gram-negative bacteria such as E. coli and total coliforms.

Effects of dietary nicotinic acid supplementation on meat quality, carcass characteristics, lipid metabolism, and tibia parameters of Wulong geese

The purpose of this study was to evaluate the effects of nicotinic acid (NA) supplementation on the meat quality, carcass characteristics, lipid metabolism, and tibia parameters in Wulong geese. A total of 360 twenty-nine-day-old Wulong geese were randomly divided into 6 treatments, and each treatment included 6 pens with 10 birds per pen. Birds were fed a basal diet supplemented with 0, 20, 40, 60, 80, or 100 mg/kg NA for 12 wk. Dietary NA supplementation linearly decreased L* value and increased pH and water-holding capacity in the breast muscle (P < 0.05). Increasing NA levels linearly and quadratically decreased shear force of breast muscle (P < 0.001). Dietary NA supplementation linearly reduced the thickness of subcutaneous fat plus the skin and percentage of abdominal fat, and enhanced the width of intermuscular fat band (P < 0.001). Dietary NA addition linearly and quadratically increased intramuscular fat (IMF) content (P ≤ 0.001). Increasing NA levels decreased serum total cholesterol and low-density lipoprotein cholesterol levels and increased serum lipase activity and hepatic mRNA expression of lipoprotein lipase in a linear manner (P < 0.05). There were linear and quadratic effects in serum triglycerides and high-density lipoprotein cholesterol (HDL-C) levels and malate dehydrogenase activity with the NA addition (P < 0.05). Feeding the NA-supplemented-diets linearly increased tibia length, circumference, fat-free dry weight, and ash content (P < 0.001). There were linear and quadratic increases in Ca and P contents with the NA supplementation (P < 0.05). According to the quadratic regression analyses fitted to shear force, IMF content, serum triglycerides and HDL-C levels, and tibial Ca and P contents, the optimal dietary NA supplementation was 80 to 90 mg/kg. In conclusion, NA addition enhanced meat quality and IMF content, regulated lipid metabolism, and increased tibia quality of Wulong geese. The dosage of 80 mg/kg NA in Wulong geese aged 5 to 16 wk was recommended.

Effects of combined ultrasound and low-temperature short-time heating pretreatment on proteases inactivation and textural quality of meat of yellow-feathered chickens

This study aimed to investigate the effect of combined ultrasound and low-temperature short-time heating (ULTSTH) (40 kHz, 0.2 W/cm² at 55 °C for 15 min) as pretreatment on proteases inactivation and textural quality of yellow-feathered chicken (YFC). Results showed ultrasound and low-temperature heating synergistically improved the inactivation of the most important meat proteases, calpain, cathepsin B and total proteases, with kinetics following the first order decay(s). Degradation of meat proteins was effectively reduced by ULTSTH compared to the pretreatment of chilling. Importantly, ULTSTH increased the firmness of breast meat and led to improved texture and microstructure. Lipid and protein oxidation of meat pretreated with ULTSTH were reduced during refrigerated storage period. Additionally, microorganisms in meat were inactivated by ULTSTH, which resulted in an obvious increase in the shelf life of meat. These findings suggested that ULTSTH is promising as an alternative pretreatment to obtain a favorable textural quality of YFC.

Effects of subzero saline chilling on broiler chilling efficiency, meat quality, and microbial safety

The poultry industry has attempted to improve carcass chilling efficiency, meat quality, and product safety. The purpose of this research was to investigate the effects of subzero saline chilling on carcass chilling, breast fillet tenderness, and microbial safety. After evisceration, broiler carcasses were chilled using ice slurry control (0% NaCl/0.5°C) or subzero saline solutions (3% NaCl/-1.8°C and 4% NaCl/-2.41°C). Broiler carcasses in the subzero saline solutions were chilled efficiently and reduced the chilling time by 11% in 3% NaCl/-1.8°C and 37% in 4% NaCl/-2.41°C over the ice slurry chilling. The breast fillets of broiler carcasses in 4% NaCl/-2.41°C were significantly tenderized than those in water control (P < 0.05), with an intermediate value observed in 3% NaCl/-1.8°C. Before chilling, broiler carcasses possessed mesophilic aerobic bacteria, Escherichia coli, and total coliforms for 3.81, 0.78, and 1.86 log cfu/g, respectively, which were significantly reduced after chilling in 3% NaCl/-1.8°C or 4% NaCl/-2.41°C solution over the water control (P < 0.05), except the mesophilic aerobic bacteria. Based on these results, chilling of boiler carcass in 4% NaCl/-1.8°C solution appears to improve carcass chilling efficiency, meat tenderness, and bacterial reduction for E. coli and total coliforms.