Conventional Chilling Research Articles

LC-MS-based metabolomics reveals metabolite dynamic changes of beef after superchilling early post-mortem

To explore the underlying mechanisms by which superchilling (SC, −3 °C within 5 h of slaughter) improves beef tenderness, an untargeted metabolomics strategy was employed. M. Longissimus lumborum (LL) muscles from twelve beef carcasses were assigned to either SC or very fast chilling (VFC, 0 °C within 5 h of slaughter) treatments, with conventional chilling (CC, 0 ∼ 4 °C until 24 h post-mortem) serving as the control (6 per group). Biochemical properties and metabolites were investigated during the early post-mortem period. The results showed that the degradation of μ-calpain and caspase 3 occurred earlier in SC treated sample, which might be attributed to the accelerated accumulation of free Ca2+. The metabolomic profiles of samples from the SC and CC treatments were clearly distinguished based on partial least squares-discriminant analysis (PLS-DA) at each time point. It is noteworthy that more IMP and 4-hydroxyproline were found in the comparison between SC and CC treatments. According to the results of metabolic pathways analysis and the correlation analysis between traits related to tenderness and metabolites with significant differences (SC vs. CC), it can be suggested that the tenderization effect of the SC treatment may be related to the alteration of arginine and proline metabolism, and purine metabolism in the early post-mortem phase.

Quality evaluation of frozen and chilled fish: A review

AbstractAs fish is a perishable food item, multiple storage approaches need be considered to extend its shelf‐life, safety, and quality. Despite advancements in modern frozen storage techniques, chilling and freezing remain the most frequently employed preservation practices onboard. The purpose of this review is to outline ways of increasing the shelf‐life of fresh and frozen fish by assessing different conventional chilling and freezing conditions. Although there are additional elements that determine fish shelf‐life, such as the fish species, harvesting method, stress experienced after being captured, amount of ice, frozen storage temperature, and time are some of the most important factors. Furthermore, the way that fish is stored (whole, filleted, or gutted) influences the final product quality. Most studies show that the entire chilled or frozen fish has a longer shelf life as compared to the gutted and filleted fish. But other facts about the species, the way it is caught, and how it gets to preparedness at industries must be taken into account if the shelf life is to be extended. Meanwhile, this review could be helpful for the prolonged shelf‐life and quality at the industrial scale and household storage.

Effects of hot or cold boning on the freshness and bacterial community changes of lamb cuts during chilled storage

Deboning methods are vital during fresh meat processing, influencing the evolution of spoilage. In this study, we examined the effects of deboning methods (including hot boning (HB), conventional chilling and boning (CCB) and very fast chilling and boning (VFCB)) on freshness and bacterial changes of lamb cuts stored at 4 °C. The freshness of lamb was evaluated by total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), total viable count mesophilic (TVCm) and total viable count psychrophilic (TVCp), and the bacterial community was determined by 16S rRNA high-throughput sequencing. The results showed basically no significant difference in the freshness indicators between HB and CCB lamb, and those of VFCB lamb were significantly lower than HB and CCB lamb except TBARS. In the early and mid storage, Pseudomonas and Ralstonia were dominant in HB lamb and norank_f_Mitochondria was dominant in CCB and VFCB lamb. In the end of storage, Pseudomonas was dominant in all lambs. Furthermore, the nutrient metabolism and some pathways potentially involved in cellular interaction might be prominent during lamb spoilage. Our work can provide information for delaying spoilage and supporting the high-quality development of raw lamb.

The underlying mechanisms of the effect of superchilling on the tenderness of beef Longissimus lumborum

This study investigated the effect of superchilling (−30 °C until the core temperature achieved −3 °C, then stored at −1 °C until 24 h, SC) on the tenderness of hot boned beef M. longissimus lumborum (LL), with very fast chilling (−30 °C until the core temperature achieved 0 °C, then stored at −1 °C until 24 h, VFC) and conventional chilling (0– 4 °C for 24 h, CC) as the controls. The lowest initial shear force values were obtained in SC samples compared to those from the VFC and CC treatments (P < 0.05). Clear freezing damage of muscle fibers and more myofibril fragmentation were found in SC samples compared with the other samples early post-mortem. Moreover, SC samples showed the highest level of inosine 5-monophosphate at 3 h post-mortem (P < 0.05). A reduced glycolysis rate (as evidenced by lactate content) was also found in SC treated samples suggesting little contribution of glycolysis on the tenderization of SC.

Effect of the combination of superchilling and super-chilled storage on shelf-life and bacterial community dynamics of beef during long-term storage

This study investigated the effect of superchilling (−30 °C until the core temperature achieved −3 °C, and − 1 °C until 24 h, SC) on shelf-life and bacterial community dynamics of beef loins, with a typical very fast chilling (−30 °C until the core temperature achieved 0 °C, and − 1 °C until 24 h, VFC) and conventional chilling (0– 4 °C for 24 h, CC) as controls. The super-chilled storage (−1 °C) was adopted after each chilling procedure, and physicochemical traits and microbiological quality were evaluated during a long-term storage. No remarkable adverse impact on meat color and lipid oxidation were observed in SC treatment. The bacterial composition results showed that Carnobacterium spp. were the main bacteria in SC treatment in the late storage period (63– 84 days). The loss of Lactobacillus spp., due to the “ultra-low temperature” during the superchilling, might be the reason that the SC did not result in a longer shelf-life compared with CC samples.

Quantification of the Effects of Electrical and CO2 Stunning on Selected Quality Attributes of Fresh Pork: A Meta-Analysis.

Simple SummaryStunning is an important and statutory pre-slaughter process that aims to induce a state of unconsciousness and insensibility to pain just before sticking and bleeding out. In Europe, two main stunning methods that are applied at pig slaughter are electrical (ES) and gas stunning with high-concentration carbon dioxide (CO2). Stunning is not only crucial in terms of the welfare of pigs at slaughter, but it may also have effects on meat quality. Various studies have compared these two methods with respect to meat-quality traits. In several studies, stunning with CO2 has been shown to improve meat quality in comparison with ES; however, other research indicated that ES enhanced the meat quality as opposed to CO2 or had no significant effect. The current study analysed the combined results of independent research and experiments to achieve quantitative evidence of the effects of two stunning methods, electrical and gas with a high concentration of carbon dioxide, on selected quality attributes of fresh pork. The results of the meta-analysis revealed that relative to CO2 stunning, overall, ES pigs had a lower pH1, higher drip loss (DL) and lightness (L*). However, the greater alterations in these traits were achieved with the application of the head-to-back (HB) electrical-stunning method and conventional chilling (Conv.) of the carcasses. The results of the meta-analysis provide evidence that differences between these two stunning methods in DL and L* may be diminished by the application of the head-only (HO) or head-to-body (HBO) method, followed by the fast chilling of the carcasses.Stunning is a statutory pre-slaughter process that may affect the quality of pork. The objective of this study was quantification of the effects of stunning (ES vs. CO2 stunning) on selected quality attributes of pork, using a meta-analytical approach. Data from 18 publications with 46 individual experiments were combined using a random-effect model to estimate the effect size of stunning on the initial and ultimate pH (pH1, pHu); drip loss (DL); colour (lightness—L*, redness—a*, yellowness—b*); and tenderness (expressed as Warner–Bratzler shear force, WBSF) of pork. In overall, loins from ES showed significantly lower pH1 (by 0.08 units); greater DL (by 0.68 p.p.); higher L* (by 1.29 units); and a* (by 0.80 units) as they compared to those from CO2 stunning. In subgroups, a greater-than-overall negative change in pH1, pHu, DL, L* and a* was detected with the application of the head-to-back (HB) stunning method. Additionally, alterations in DL and L* may be magnified with the application of conventional chilling (Conv.) to ES pigs. There was no effect of stunning on WBSF but, due to a low number of research in the database, the reliability of these results may be misleading. These results provide evidence that the differences between these two stunning methods in DL and L* may be diminished by the application of the head-only (HO) or head-to-body (HBO) method, followed by the fast chilling of carcasses.

73 Commercial Management of Fresh Pork Quality Using Post-Mortem pH and Temperature Declines

Abstract Historically, research involving the pH decline of pork has been conducted under university conditions with the use of electrical stunning and conventional chilling (minimum temperature &amp;gt; -10). Most large commercial slaughter plants in the U.S. currently use CO2 stunning and many have some form of accelerated chilling of the carcass. With ante-mortem stress level of the pig and post-mortem carcass temperature decline being 2 of the major factors affecting post-mortem pH decline rate, it should be expected that the pH decline rate may be different in current commercial conditions when compared with the literature. Our work has focused on developing methods to measure pH and temperature decline in short intervals (5 min, 15 min, 30 min, or 1 h) and determine the critical time periods to manage the chilling process in order to slow pH decline and obtain higher ultimate pH levels (20h). This research indicates the potential to alter the carcass chill curve to make precision adjustments in the quality of pork.

The impact of carcass size, chilling, and electrical stimulation on beef postmortem temperature and pH decline

Variability in carcass size can influence carcass chilling rates which could result in issues associated with beef tenderness and color. Moreover, the usage of electrical stimulation can affect postmortem metabolism and meat quality. However, few studies have looked at the combined impact of chilling and electrical stimulation on temperature decline, postmortem biochemistry, and color among the current consist of US beef. Beef carcasses (N =162, &amp;lt; 30 months) were randomly selected from two beef processing plants. One side of each carcass was electrically stimulated (ES), while the opposing side was not electrically stimulated (NES). Matched sides were subjected to either conventional spray chilling (CONV) or delayed-spray chilling (DELAY). Deep tissue (10.5-cm under the pelvic bone) and surface temperature (1.5-cm under the loin fat) were continuously monitored during chilling in addition to temperature and pH measurements from the semimembranosus (SM), longissimus lumborum (LL), and psoas major (PM) muscles at an initial time (45 to 60 min), 6 h, 12 h, and after chilling (28 to 36 h) postmortem. Further, the instrumental (L*, a*, and b*) and visual color of the PM were evaluated. For data analysis, carcasses with hot carcass weights above or below the average were considered heavy or light, respectively. A nonlinear regression model was fitted to the continuous deep and surface temperatures, whereas other parameters were evaluated using a mixed model. Electrical stimulation improved (P &amp;lt; 0.05) the color of PM in light weight carcasses, but not (P &amp;gt; 0.05) in heavy weight carcasses. Temperature decline was faster (P &amp;lt; 0.05), and pH decline slower (P &amp;lt; 0.05) in the SM and LL of light weight carcasses under CONV. Exponential decay models for deep and surface temperatures indicated the rate of cooling differed (P &amp;lt; 0.05) due to the combination of treatment factors. Heavy weight carcasses in DELAY had slower rates of temperature decline (P &amp;lt; 0.05). Overall, the variability in carcass size affected temperature decline and postmortem metabolism. Therefore, postmortem management practices should consider carcass weights to ensure homogeneous meat quality.

Spray chilling on carcass weight loss, and physicochemical and microbiological quality of beef cuts during storage

ABSTRACT: Different chilling treatments are used before meat storage. The effect of spray chilling (SC) on meat quality appears to vary. Here, we investigated the effects of SC on beef carcass weight loss and meat quality during subsequent storage. The 2-h SC program tested involved 180-s initial spraying, followed by 60-s spray cycles at 540-s intervals. Deboned chuck tender (IMPS 116B) beef cuts were vacuum-packaged and stored for up to 60 d. Purge and cooking losses, Warner-Bratzler shear force, meat colour [CIE L*, a*, b*], and microbiological quality were evaluated. SC reduced carcass weight loss (P&lt;0.001) compared with conventional chilling. However, storage time affected the purge and cooking losses, and Warner-Bratzler shear force. CIE a* and b* values increased (P&lt;0.05) after 30-d aging in both chilling treatments. Pronounced psychrotrophic growth was observed during storage after both treatments. In conclusion, SC can be used to reduce the economic losses associated with meat chilling, without affecting meat quality attributes.

Effects of chilling rate on the freshness and microbial community composition of lamb carcasses

The freshness and microbial community composition of lamb carcasses were evaluated under three chilling rates treatments: conventional chilling (chilling rate was 1.76 °C/h), very fast chilling-I (VFC-I, chilling rate was 12.52 °C/h), and very fast chilling-II (VFC-II, chilling rate was 14.52 °C/h). The results showed that the freshness indicator including total viable counts (TVC), total volatile basic nitrogen (TVB-N), and thiobarbituric acid reactive substance (TBARS) values of VFC-II treatment were lower than conventional chilling and VFC-I treatments, and the bacterial species richness of the three treatments increased with the extension of storage time. The VFC-II treatment could inhibit the growth of Psychrotrophs and Corynebacterium. At the genus level, the Psychrotrophs became the main dominant spoilage bacterium, and the Turicibacter, Macrococcus, and Brevibacterium were positively correlated with TVB-N significantly. The chilling methods affected the initial diversity of microbiota, and the higher diversity of the microbial community was, the lower abundance of carbon metabolism and purine metabolism was. In conclusion, the VFC-II treatment is conducive to the preservation of lamb carcass.

The effect of chilling method on quality of pork with elevated glycogen stores

The objective of this study was to examine the effect of accelerated chilling (AC) on selected attributes of LLWH (Landrace × Large White) × Hampshire pork with elevated glycogen stores. Investigation showed that application of accelerated chilling compared to conventional chilling reduced the temperature of longissimus muscle, increased ultimate pH (pH48), and significantly decreased lightness (L*) and yellowness (b*) of meat at 48 hr postmortem without any effect on drip loss. Muscles with high (GP ≥ 180 µmol/g) glycogen stores from AC treatment produced less lactate than those from CC (conventional chilling) treatment. However, longissimus muscles exhibited low ultimate pH and elevated drip loss regardless of the type of the chilling treatments. Practical applications The investigation has shown that application of accelerated chilling (regardless of glycogen stores) has however a very limited ability to improve the quality of LLWH fatteners. The application of AC may reduce lactate production in muscles with high glycogen stores, but cannot prevent negative alterations in meat quality. Thus, the use of this treatment for pork with elevated glycogen stores seems negligible and commercially unjustified.

Electrical stimulation extends the time limits for very fast chilling of lamb loins

Context Very fast chilling (VFC) involves cooling meat to approximately –1°C before the onset of rigor, and offers potential benefits compared with conventional chilling that include accelerated tenderisation, improved shelf life and reduced inventory costs. However, the practical difficulties of achieving the required temperature profile prevents adoption of VFC commercially. Aims The objective of this study was to determine if electrical stimulation could be a way of making VFC easier to achieve for lamb meat. The hypothesis tested was that electrical stimulation would reduce the rate of chilling required with very fast chilling by accelerating the rate of pH decline post-mortem. Methods The experiment was a 2 × 3 factorial design whereby 54 loins from 27 lambs were allocated to one of six different treatments: no electrical stimulation and electrical stimulation, and chilling rates to reach −1°C at 1 h (Fast), 1.5 h (Moderate) and 2.5 h (Slow) post-mortem respectively. Key results Without electrical stimulation, shear forces were lowest for the Moderate chilling rate; but with electrical stimulation, consistently low shear force values were obtained with all chilling rates. Muscle pH depended on treatment, although this effect also depended on the time post-mortem. Shear force depended on chilling rate only when there was no electrical stimulation. Without electrical stimulation, the optimal chilling rate was the Moderate treatment. Effects on sarcomere length accounted for some, but not all, of the effects of treatment on shear force. Conclusions Electrical stimulation therefore reduced the chilling rate required to optimise tenderness with VFC, and could be a component of a practical VFC regime for lamb meat. Implications VFC could become a practical chilling method, but only when sensory evaluation supports the favourable shear force findings established in this study. This would require evaluation of VFC at a commercial scale.

Timing and duration of low voltage electrical stimulation on selected meat quality characteristics of light and heavy cattle carcasses

Context The present study investigated the effects of several electrical-stimulation parameters with conventional chilling of heavy- and light-grade carcasses from commercial feedlot cattle on selected meat-quality attributes. Aims The aim was to determine the combination of electrical-stimulation parameters that produced the most desirable results in terms of meat quality, which will serve as a guide to processors seeking to enact best processes in the meat industry. Methods Low-voltage electrical stimulation (110 V peak, 17 pulses/s, 5-ms pulse width) was applied either early post-mortem (PM) at 7 min or late PM at 45 min, for either 30 or 60 s on steer carcasses (n = 98) divided into two weight categories (light (≤260 kg) and heavy (≥290 kg) grades). The Longissimus lumborum muscle was evaluated for sarcomere length, myofibril fragment length (MFL), calpain-1, calpastatin, shear force and drip loss (3 and 14 days PM). Key results There were no significant differences in sarcomere length and no sarcomere shortening was observed. There were minor inconsistencies where early stimulation coincided with marginally longer MFL at 3 and 14 days PM, while late stimulation produced the shortest MFL at 14 days PM. Higher decline in calpain-1 concentration (mean 36.2%) was recorded in the early stimulated carcasses compared with the late stimulated carcasses (mean 29.7%) from 1 to 24 h PM, while calpastatin concentration decreased at a similar rate (mean 24%). Early stimulation resulted in lower shear force (P &amp;lt; 0.05) at 3 days PM, especially in the heavier carcasses, indicating that higher initial temperature did accelerate tenderisation. At 14 days PM, there were no significant differences in shear force as regards stimulation time or carcass weight. Higher drip loss was however recorded in the early stimulated carcasses. Conclusions Early application of low-voltage electrical stimulation produced faster tenderisation early PM, due to higher rigor temperature, but, after aging for 14 days, all meat was acceptably tender with a lower variability, regardless of the stimulation time and carcass weight. Higher drip loss was associated with higher tenderness, which is normal and not a defect. Implications The use of low-voltage electrical stimulation should be encouraged for its ability to reduce variability in meat quality due to carcass-weight differences, especially in the current feedlot systems.

Effect of sub‐freezing storage (−6, −9 and −12 °C) on quality and shelf life of beef

SummaryBased on the results of low field nuclear magnetic resonance (LF‐NMR) in our current study (the frozen state of −6, −9 and −12 °C were nearly the same with extremely low free water content), −6, −9 and −12 °C was designated as sub‐freezing temperatures. The effects of sub‐freezing storage compared with conventional chilling (4 °C), superchilling (−1 °C) and conventional freezing (−18 °C) on the quality and shelf life of beef were analysed. Results showed that the shelf life of beef is extended to 84 and 126 day at −6 °C and −9 °C, respectively. However, the TVB‐N values of the samples stored at −12 °C and −18 °C remained below 15 mg/100 g even on 168 day. Furthermore, shear force, colour, pH, thiobarbituric acid reactive substances (TBARS) and sensory properties were also measured. Consequently, the sub‐freezing storage has significantly extended the shelf life of beef compared to chilling and superchilling (P &lt; 0.05). Moreover, no significant difference (P &gt; 0.05) was found between the indicators for quality and shelf life of samples stored at −12 and −18 °C throughout 168 days.

The Influence of Time and Temperature at Carcass Boning on the Consumer Assessment of Eating Quality of New Zealand Beef

ObjectivesA consumer sensory panel was conducted to compare the palatability traits of New Zealand beef muscles that were either conventionally chilled or hot boned.Materials and MethodsForty carcasses were selected initially for the study. Sides from each carcasses were randomly assigned to either conventional chilling (CB) or hot boning (HB). Five subprimals were removed including the strip loin, cube roll, tenderloin, rump, and topside. Accessory muscles were removed from each subprimal leaving only the longissimus lumborum (LL), longissimus thoracis (LT), psoas major (PM), gluteus medius (GM), and semimembranosus (SM). HB muscles were removed within 90 min of slaughter. The CB sides were chilled overnight prior to fabrication. Subprimals were fabricated into 2.5 cm steaks and were appointed to one of three postmortem aging periods (7, 21, or 35 d). Steaks were cooked on a Silex clamshell grill (Model S-143K, Silex Grills Australia Pty Ltd., Marrickville, Australia) with a temperature set at 225°C for a predetermined time and rested 3 min prior to serving. Consumers rated tenderness, juiciness, flavor liking, and overall liking on 100- mm line scales. A total of seven samples were served to each consumer. Data were analyzed by muscle as a split plot design using the GLIMMIX procedure of SAS (SAS Inst. Inc., Cary, NC) with chilling treatment as the whole plot fixed effect and postmortem aging as the sub plot fixed effect. Carcass was included as a random effect. Treatment least squares means were separated using the PDIFF option (P < 0.05).ResultsNo 2-way interactions for chilling treatment or aging were observed for any consumer eating quality traits. Chilling treatment did affect tenderness, juiciness, and overall liking of the LT with CB being greater (P < 0.02) HB. Chilling treatment also affected the tenderness, flavor, and overall liking of the PM as CB was greater (P < 0.01) compared to HB. Finally, chilling treatment affected the SM for tenderness, juiciness, flavor, and overall liking; however, unlike the LT and PM, consumers scored HB SM greater (P < 0.01) than CB SM. Chilling treatment had no effect (P > 0.01) on the tenderness, juiciness, flavor, and overall liking of the GM or LL. In addition, postmortem aging affected tenderness of LT and SM with 21 d and 35 d being rated greater (P < 0.05) than 7 d samples. Postmortem aging also affected (P < 0.05) the tenderness, juiciness, flavor liking, and overall liking of the LL with consumers scoring 35 d samples most favorably, 21 d intermediate, and 7 d the lowest. Postmortem aging did not affect (P > 0.05) the tenderness, juiciness, flavor liking, or overall liking of the GM or PM.ConclusionThese results indicate that chilling treatment and postmortem aging had an impact on eating quality, but these results varied by muscle. Based on consumer evaluations of these five muscles, hot boning is not recommended for LT or PM due to the reduction of eating quality scores for these subprimals; however, hot boning and early removal of muscles like the SM benefited from an eating quality standpoint and was neutral for the strip loin and rump. Processors must weigh the benefits and disadvantages hot boning may have on a subprimal basis when determining if this practice should be implemented in their facilities.

The Effects of Hot vs. Cold Boning on Eating Quality of New Zealand Grass Fed Beef

Sides of the 40 selected carcasses were alternately assigned to both conventional chilling and cold boning (CB) or hot boning (HB). Fabrication of CB sides took place after overnight chilling (20 h postmortem) and subsequent carcass grading, while fabrication of HB sides occurred on the day of slaughter within 60 min of exsanguination. Five muscles were removed, including the longissimus lumborum (LL), longissimus thoracis (LT), psoas major (PM), gluteus medius (GM), and semimembranosus (SM) for consumer evaluation, compositional analysis, and sarcomere length determination. Cold boning muscles had longer (P &lt; 0.05) sarcomere lengths compared to HB muscles, expect for the GM and SM. Chilling treatment and postmortem aging (7, 21, or 35 d postmortem) had an impact on eating quality, but these results varied by muscle. Cold shortening could be responsible for the differences in sarcomere length and ultimately differences in tenderness between HB and CB muscles. Based on consumer evaluations, HB is not recommended for LT or PM due to the reduction (P ≤ 0.02) of tenderness and overall liking scores for these subprimals; however, HB and early removal of muscles like the SM benefited (P &lt; 0.01) from an eating quality standpoint for all palatability traits, and was neutral (P ≥ 0.21) for tenderness, juiciness, flavor, and overall liking of the LL and GM. Postmortem aging did not affect (P ≥ 0.07) eating quality of the GM and PM, but improved (P &lt; 0.01) tenderness of LT and SM, as well as the tenderness, juiciness, flavor liking, and overall liking of the LL.

Influence of rapid chilling on biochemical parameters governing the water‐holding capacity of pork longissimus dorsi

SummaryThe aim of this study was to investigate the effects of rapid chilling (RC) of carcasses on the quality of pork longissimus dorsi (LD) compared to conventional chilling (CC). Carcasses subjected to RC were chilled at −20 °C for 1.5 h and then moved to 4 °C until 24 h post‐mortem, while carcasses that were CC were placed directly in a chill at 4 °C for 24 h post‐mortem. RC accelerated the rates of temperature decline post‐mortem (P &lt; 0.01) and increased pH values at 1.5 and 8 h post‐mortem (P &lt; 0.05). RC could significantly decrease the denaturation of myosin and sarcoplasmic proteins during post‐mortem ageing. Samples of RC had a significant lower purge loss compared to CC group during post‐mortem ageing (P &lt; 0.05). Our study implies that RC could influence the biochemical changes of pork LD which may further regulate water‐holding capacity during post‐mortem ageing.

Effects of feeding high protein canola meal on dry cured and conventionally cured bacon

The aim of this study was to determine the effects of blast chilling of pig carcasses on the physiochemical and sensory properties of the longissimus lumborum muscle. To this end, right half-carcasses were blast-chilled for 70 min at − 24 °C and then for 22 h and 50 min at 1 °C, while left half-carcasses were chilled conventionally at 1 °C for 24 h. At 2 h and 6 h post mortem, blast chilling had significantly reduced the temperature of the carcasses, as well as the rate of pH decrease and the rate of increase in EC. It had no significant effect on the ultimate pH or its range, or on EC at 24 h post mortem, but it significantly lowered L*, b*, C* and drip loss compared to the conventionally chilled carcasses. Blast chilling adversely affected sensory characteristics such as tenderness and flavor. There were no significant differences between the effects of blast and conventional chilling systems on meat quality between conformation classes.

The effects of blast chilling on pork quality

The aim of this study was to determine the effects of blast chilling of pig carcasses on the physiochemical and sensory properties of the longissimus lumborum muscle. To this end, right half-carcasses were blast-chilled for 70min at −24°C and then for 22h and 50min at 1°C, while left half-carcasses were chilled conventionally at 1°C for 24h. At 2h and 6h post mortem, blast chilling had significantly reduced the temperature of the carcasses, as well as the rate of pH decrease and the rate of increase in EC. It had no significant effect on the ultimate pH or its range, or on EC at 24h post mortem, but it significantly lowered L*, b*, C* and drip loss compared to the conventionally chilled carcasses. Blast chilling adversely affected sensory characteristics such as tenderness and flavor. There were no significant differences between the effects of blast and conventional chilling systems on meat quality between conformation classes.

Poultry Carcasses Chilled by Forced Air, Water Immersion and Combination of Forced Air and Water Immersion

Conventional chilling methods such as forced air (FA) and water immersion (WI) are used in the industry to chill poultry carcasses from approximately 40 to 4C, which is essential to improve safety. Besides both processes, a combined method (CO) of WI and FA has been reported in the literature. The objective of this investigation was to compare the chilling of poultry carcasses by FA, WI and CO using an experimental apparatus specially designed for this purpose. Time-temperature evolutions of pectoral muscle and carcass mass variations during the chilling processes were determined under different chilling conditions, comprising different air velocities and relative humidities (RH). The results showed that it is possible to reduce the water loss (approximately 50%) and chilling time (reduction between 14.5 and 1.5%) of FA process using CO process. Air velocity and RH ranges can be varied to take advantage of evaporative chilling and to reduce the carcasses water loss. Practical Applications In the factories, poultry carcasses are chilled from approximately 40 to 4C by water immersion, which is crucial to ensure safe products. However, air chilling (AC) has been often used for safety reason and due to the limited availability of water. On the contrary, wetting the carcasses avoids excessive moisture loss in air chillers, whereas the evaporation of the water adhered to the carcass surface may assist the chilling process. The present paper evaluates the effectiveness of AC and of a combined chilling method (CC) (AC combined with water immersion chilling) of poultry carcasses at different relative humidity and air velocities. The results showed that the CC process was shorter and reduced carcasses weight loss compared with the AC process.