Dry Pork Research Articles

Prevalence of carcass lesions and their effects on welfare, carcass composition and meat quality in slaughtered pigs

Abstract The aims of this study were to determine the prevalence of carcass lesions in slaughtered pigs and to quantify their relationships with different animal characteristics, pre-slaughter factors, blood measurements, performance indices, carcass composition and meat quality traits. Data was recorded for 30 journeys referring to 1080 market-weight pigs that originated from 15 commercial small-scale finishing farms. Carcass lesions were visually assessed on the slaughterline in different parts of the carcass, i.e., anterior, middle and posterior, using a three-point scale. Complete blood count was investigated. The following performance indices and carcass composition traits were measured: average lifetime daily weight gain, live, hot and cold carcass weights, cooler shrinkage, dressing percentage, backfat thickness and meatiness. Meat pH and temperature were measured 45 minutes postmortem. Of the 1080 pigs slaughtered in 30 batches, 70.28% displayed some degree of lesions on the carcass (moderate – 30.00%; severe – 40.28%). The carcass lesions were the most prevalent (50.20%) in the posterior part of the pig carcass. RYR 1 genotype, live weight, loading density, lairage time, lairage density and slaughter season affected the carcass lesion prevalence. The presence of carcass lesions, irrespective of severity, was associated with alterations in blood measurements in slaughtered pigs, indicating compromised animal welfare. The presence of severe carcass lesions in slaughtered pigs was significantly associated with increased meat pH45min, which led to the highest occurrence of dark, firm and dry pork. In contrast, there was strong evidence of association between the presence of moderate carcass lesions in slaughtered pigs and both decreased meat pH45min and increased meat T45min, which led to the highest occurrence of pale, soft and exudative pork among the carcass lesion groups. In conclusion, this study showed a high prevalence of carcass lesions in slaughtered pigs, whereby the risk of their occurrence was affected by both animal characteristics and pre-slaughter conditions. Also, the presence of carcass lesions in slaughtered pigs, irrespective of severity, was significantly associated with alterations in the blood measurements and pork quality.

Laparoscopic management of rare smoked dry pork bezoar in the stomach.

Medical literature recognise only 4 types of bezoar - phytobezoar, trichobezoar, lactobezoar and pharmacobezoar. Here, we discuss a new unique type of bezoar composed of undigested dry pork. A 58-year-old male patient from Nagaland, India, presented with intermittent symptoms of gastric outlet obstruction and pain abdomen. On clinical examination, he was found to have an epigastric lump. Upper gastrointestinal endoscopy showed an undigested ball of swallowed meat at the pylorus and later at the fundus on repeat endoscopy just before the surgical intervention. Endoscopic mechanical fragmentation was tried, but owing to the large size and hard sticky consistency of the bezoar, fragmentation was not feasible. Due to persistent pain abdomen and clinical gastric outlet obstruction, a decision for operative intervention was taken. He finally underwent laparoscopic anterior gastrotomy and evacuation of the bezoar. The post-operative course was uneventful, and the patient went home symptom free on the 5th post-operative day.

Accuracy assessment of different CBCT acquisition protocols used in rapid prototyping models

This study compared the acquisition protocols of the Conical Beam Computed Tomography (CBCT) system, to assess the influence on image accuracy by different voxel sizes and the presence of soft tissue. Tomographic acquisition was performed in a fresh (F) and dry (D) pork jaw with voxel sizes of 0.4, 0.3 and 0.25 mm. The gold standard was obtained by scanning dry jaws covered with barium sulfate with a voxel size of 0.25 mm. The images were treated in the MIMICS® program, and noise areas were removed manually, using a fixed threshold for the purpose of generating 3D printing windows. Each window was virtually overlaid with the gold standard using the MeshLab software, obtaining absolute error values ​​between the meshes, generating a map of discrepancies. Significant differences were found between windows D 0.30 vs. F 0.30, D 0.30 vs. F 0.25, D 0.30 vs. D 0.25, D 0.30 vs. F 0.40, F 0.30 vs. D 0.25, F 0.25 vs. D 0.25, F 0.25 vs. D 0.40, D 0.25 vs. F 0.40, D 0.25 vs. D 0.40 and F 0.40 vs. D 0.40, (p <0.05). It was observed that the dry jaw windows showed a lower mean and standard deviation when compared to the fresh jaw windows. The 0.25 mm voxel protocol showed the most accurate result and the presence of soft tissues influenced the accuracy of the image when some protocols were compared statistically.

Acetylation and Phosphorylation of Proteins Affect Energy Metabolism and Pork Quality.

Preslaughter handling has been shown to significantly affect meat quality, but the mechanisms are not fully understood. In this study, we investigated protein phosphorylation and acetylation in pig muscles at early postmortem time and their associations with meat quality attributes. Thirty pigs were randomly assigned to traditional (TH, n = 15) or mild handling (MH, n = 15). Compared with TH, MH reduced the incidence of pale, soft, and exudative (PSE) or dark, firm, and dry (DFD) pork. MH induced 65 and 20 peptides that match with 39 and 12 proteins to be more highly phosphorylated and acetylated, respectively. Creatine kinase, β-enolase, α-1,4-glucan phosphorylase, tropomyosin, and myosin heavy chain isoforms 1, 4, and 7 were found to be simultaneously phosphorylated and acetylated, which may involve glycolysis, tight junctions, and muscle contraction. The phosphorylation and acetylation levels of differential proteins showed significant correlations with meat quality traits. These findings indicate that preslaughter MH can improve meat quality by regulating protein phosphorylation and acetylation involving energy metabolism in muscle.

Organochlorine Pesticides and PCBs in Traditionally and Industrially Smoked Pork Meat Products from Bosnia and Herzegovina.

The aim of this study was to determine the concentration of 19 organochlorine pesticides (OCPs): (hexachlorocyclohexane (α-HCH, β-HCH, δ–HCH), lindane, aldrin, heptachlor, heptachlor epoxide, trans-chlordane, cis-chlordane, endosulfane I, endosulfane II, endosulfane sulfate, dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), dieldrin, endrin, dichlorodiphenyldichloroethane (DDD), methoxychlor and endrin ketone and 6 polychlorinated biphenyls (PCBs) (PCB 28, PCB 52, PCB 101, PCB 153, PCB 138 and PCB 180). The samples were taken from pancetta, dry pork neck (budiola), pork tenderloin and sausages produced in Rakitno (Bosnia and Herzegovina), smoked in both a traditional smokehouse and in an industrial chamber. Instrumental analysis was performed using gas chromatography–mass spectrometry (GC–MS). The reliability of the results, i.e., quality control is ensured by standard laboratory practice, which involves participation in proficiency test, the use of blank samples, reference materials and implementation of recommendations given by the relevant international organizations. The concentrations of α-HCH, lindane, PCB 28, PCB 52 and PCB 153 were detected and quantified. The concentrations of OCPs and PCBs did not significantly vary depending on product type and the conditions of production. All the examined samples were for human consumption.

PSV-29 Changes in the PSE and DFD porcine muscle proteome during autolysis

Abstract Despite reducing of pale, soft, exudative (PSE) pork share, its amount is 45% in Russia and 65% in Belarus of the total. Dark, firm, dry (DFD) pork occurrence increases to 20% in Russia and 30% in Belarus. Protein changes in normal (NOR), PSE and (DFD) pork muscle during 5 days ageing were studied. Were found differences in their protein profiles and potential protein markers of such raw materials were identified. Mainly in range 600–1000 Da and up to 450 Da. Analysis of the peptide composition showed two myosin light chain isoforms (MLC) (Mw/pI): MLC-like protein — 21.8/5.00 and phosphorylated MLC f -21.0/4.90, in the sample. One of which is fast, the other is slow MLC isoform. Increase in the number of fragments was noted of such proteins as pyruvatekinase, α-enolase, muscle creatine phosphokinase and GPDH, adenylatekinase, αB-crystallin. A correlation between muscle proteins breakdown (the troponin group/troponin family) and the characteristics of meat was found. In NOR samples, troponin I decomposed quite clearly. The most obvious autolysis marker is the appearance and increase of three additional fragments of fast skeletal muscle troponin T, which differ in molecular weight and pI. According to the tryptic peptides mass spectra, the C- and N-molecule terminal parts peptides are no longer detected sequentially. Moreover, in DFD samples, they are most significantly split into shorter peptides. Appearance of short N-terminal GPDH 21 kDa fragment on the 5th day of autolysis is PSE specific marker. Totally 12, 14 and 18 specific peptides were identified in chilled and 18, 32 and 38 on 5th day of autolysis in PSE, NOR and DFD pork respectively. DFD meat can be considered a source of natural specific low-molecular peptides, specifically to produce meat products with functional properties. (Research was supported by the Russian Science Foundation, project 16-16-10073)

Effect of Moringa oleifera leaf powder on drying kinetics, physico‐chemical properties, ferric reducing antioxidant power, α‐tocopherol, β‐carotene, and lipid oxidation of dry pork sausages during processing and storage

The potential of Moringa oleifera leaf powder (MLP) to limit lipid oxidation in nitrite‐free unfermented dry pork sausages (droewors) was investigated. Total phenolic compounds, α‐tocopherol and β‐carotene content of MLP was quantified. Droewors with no additives, 0.75 g/100 g MLP or 15 mg/kg vitamin E (VE) oil were processed and sampled after drying (3 days) and during 56 days of storage. Thiobarbituric acid reactive substances (TBARS) of droewors made with MLP were lower until day 10. The effects of 0, 0.5, 1, and 2 g/100 g MLP on TBARS, ferric reducing antioxidant power (FRAP) and the α‐tocopherol, γ‐tocopherol, and β‐carotene content of droewors were assessed during drying and 7 days of storage. MLP inclusion significantly increased FRAP, α‐tocopherol, and β‐carotene content. From the end of drying, TBARS of droewors formulated with MLP were significantly lower compared to droewors formulated without MLP. Increasing the MLP inclusion level had no significant effect on TBARS. Practical applications: The research assesses and demonstrates the potential of Moringa oleifera leaf powder (MLP) as a natural additive to inhibit the rate and extent of lipid oxidation in unfermented dry pork sausages (droewors) with no nitrites/nitrates added. The inclusion of MLP in pork droewors at levels ranging from 0.5 to 2 g/100 g significantly increased the antioxidant activity (FRAP) and quantity of antioxidant vitamins (α‐tocopherol, and β‐carotene) in the product. Higher inhibition of lipid oxidation (TBARS) was observed in droewors with MLP added compared to the positive (vitamin E oil) and negative (no additives) controls. The different MLP inclusion levels used in the study resulted in similar lipid oxidation inhibition. Therefore, the findings show that the application of 0.5 g/100 g MLP is sufficient to decrease lipid oxidation in pork droewors and could potentially be applied to other types of dry‐cured sausages for this purpose.

Debaryomyces hansenii Metabolism of Sulfur Amino Acids As Precursors of Volatile Sulfur Compounds of Interest in Meat Products.

The ability of Debaryomyces hansenii to produce volatile sulfur compounds from sulfur amino acids and the metabolic pathway involved have been studied in seven strains from different food origins. Our results proved that l-methionine is the main precursor for sulfur compound generation. Crucial differences in the sulfur compound profile and amino acid consumption among D. hansenii strains isolated from different food sources were observed. Strains isolated from dry pork sausages displayed the most complex sulfur compound profiles. Sulfur compound production, such as that of methional, could result from chemical reactions or yeast metabolism, while according to this study, thioester methyl thioacetate appeared to be generated by yeast metabolism. No relationship between sulfur compounds production by D. hansenii strains and the expression of genes involved in sulfur amino acid metabolism was found, except for the ATF2 gene in the L1 strain for production of methyl thioacetate. Our results suggest a complex scenario during sulfur compound production by D. hansenii.

Effect of different drying methods and packaging conditions on physicochemical and sensory attributes of phytoingredients treated pork cubes during storage

A study was conducted to investigate the effect of certain phytoingredients on the physico-chemical and sensory qualities of dry pork cubes dried by solar and oven drier. Oven-drying was done at 60°C while solar drying was done at 55-60°C. The results showed that during oven-drying and solar-drying the dry matter and protein contents of the dried samples decreased (p less than 0.05). Due to addition phytoingredients there are certain changes in the proximate composition of the dry products. TBARS values of the samples were affected due to antioxidant contents of the phytoingredients. The solar-dried samples had higher acceptability level than the oven-dried samples. The products were kept in aerobic and vaccum packaging method at room temperature and changes were observed during storage up to six months. The results were attributed to the various changes that occurred during the drying process. Solar-drying of meat samples could be adopted under the hot humid environment done under hygienic conditions.

THE REASONABILITY OF BLUEBERRY CONCENTRATED JUICE APPLICATION IN THE MANUFACTURE OF DRY-CURED PORK

The aspects of the blueberry concentrated juice application in the production of dried pork as an ingredient of the salt mixture were studied. The organoleptic evaluation of the obtained products using concentrated blueberry juice with different concentrations of solids was carried out. The chemical composition of the finished experimental products is investigated. The influence of the concentrated juice of blueberries to the number of QMAFAnM on the surface of the product (bacteriostatic effect). It is shown that dry-cured pork, injected with a salt mixture with concentrated blueberry juice, has higher taste and aromatic characteristics, improved consistency. In this work, the chemical composition of experimental samples of dry-cured pork is evaluated. It is shown that the use of concentrated blueberry juice in salting increases the moisture content and essential micronutrients. Was found that the number of mesophilic aerobic and facultative-anaerobic microorganisms depends on the amount of dry substances, in particular organic acids, in concentrated blueberry juice, namely, with an increase in the concentration of blueberry juice used in the salt mixture, the amount of QMAFAnM on the surface of the product decreases. Concentrated blueberry juice acts as an inhibitor of growth of pathogenic microflora. On the basis of the conducted researches the optimum content of dry substances for application of the concentrated juice from blueberries at a salting of dry pork is established.

Preslaughter handling practices and their effects on animal welfare and pork quality.

At all times, prior to slaughter, pigs may experience stress from a range of handling practices, such as fasting, loading and transport, mixing, and interaction with humans. These factors can affect the welfare of pigs and carcass and meat quality, both individually and collectively. Preslaughter stress is both an animal welfare and a meat quality issue. Behavioral and physiological studies have revealed that poor handling practices at the farm, during transport and at the slaughter plant, have an adverse effect on pigs and may result in the loss of profits due to animal losses during transport and in lairage. Also, poor preslaughter handling can also lead to losses in carcass value as a result of reduced yield, the presence of lesions and bacterial contamination, and meat quality defects (e.g., pale, soft, exudative and dark, firm, dry pork). These economic losses can be limited by improving the design of facilities, controlling the environmental conditions, and implementing training programs for the correct animal handling at any stage preslaughter. The objective of this review was to review research findings on the effects of preslaughter practices on ante-mortem behavioral and physiological response in pigs, including muscle metabolism, and to provide recommendations aimed at limiting the impact of preslaughter handling on animal losses and pork quality.

Effect of surimi on quality characteristics of dry and semi-dry (non-fermented) pork sausages during cold storage

This study was conducted to investigate the effect of dry conditions and surimi addition on physicochemical properties of pork sausages during cold storage. Experimental designs are as follows (T1; semi-dry pork sausage, T2; semi-dry pork sausage with 14.04% surimi, T3; dry pork sausage, T4; dry pork sausage with 14.04% surimi). The dry condition and surimi addition interaction factors significantly affected the quality characteristics including: pH, moisture content, shear force, salt content, CIE color, whereas the texture properties were only affected by the dry condition in the sausages (P < 0.05). The storage characteristics including TBARS, volatile basic nitrogen, and growth of microorganisms were also influenced by these factors during cold storage (P < 0.05). The drying and surimi treat increased the TBARS and volatile basic nitrogen values, whereas decreased the microorganism counts of pork sausages during cold storage. As results, the physicochemical properties of pork sausages could be improved by the meat processing methods such as drying method and surimi addition.

The Influence of Pre-Mortem Conditions on Pale, Soft and Exudative (PSE) and Dark, Firm and Dry (DFD) Pork Meat

Abstract The aim of this study was to determine the effect of gender, stocking density in the transport vehicle, lairage time and season on the incidence of skin lesions on pig carcasses and PSE and DFD meat. Skin lesions on carcasses (480, in total) were assessed according to the Welfare Quality® protocol (2009). The pH and temperature measurements were performed 45 minutes after slaughter. The group of carcasses with skin lesions score 2 had significantly higher incidence of PSE and DFD meat compared to the groups of carcasses with skin lesions score 0 and 1. With regard to gender, there were no differences in meat quality parameters, as well as for the incidence of skin lesions and PSE and DFD meat. The results showed that a space allowance lower than 0.3 m2/100 kg and higher than 0.5 m2/100 kg pig had a detrimental effect to animal welfare and meat quality. Lairage time affected meat quality parameters, incidence of skin lesions score and PSE and DFD meat, where after long lairaging (&gt; 17 h) mean pH45 and t45 values became significantly higher, as well as the incidence of skin lesions and DFD meat. After short lairaging (&lt; 1 h) mean pH45 value became significantly lower, while mean t45 value and the incidence of PSE meat became significantly higher. A significantly higher number of skin lesions on the carcass were observed in winter compared to all other seasons. High temperatures during summer and low temperatures during winter had a negative influence on meat quality parameters and incidence of PSE and DFD meat.

Effect of sodium chloride reduction in dry pork on sensory quality parameters and instrumentally measured colour

The aim of this paper was to examine sensory properties and instrumentally measured colour of dry pork produced with less amount of sodium chloride. Trial was consisted from five batches, two control and three experimental. Pork from control group was cured with 6% nitrite curing salt (C1 group) and with 3% nitrite curing salt (C2 group), respectively. Pork from 1st experimental group was produced with 2% nitrite curing salt and 1% potassium chloride; pork from 2nd experimental group was produced with 1,5% nitrite curing salt and 1,5% potassium chloride; dry meat from 3rd experimental group was produced with 2% nitrite curing salt and 1% ammonium chloride. Curing process lasted for 7 days; smoking, drying and ripening for 21 days. In final products, water activity, moisture, protein and fat content was determined. Taste was best evaluated in dry pork from C2 group and worst in dry pork from 2nd group. The most expressed saltiness was determined in dry pork from the first control group (C1) that corresponded to the largest amount of added salt. Due to most expressed bitter taste, the evaluation for overall acceptability for dry meat from the second experimental group was the lowest. The evaluation for overall acceptability of dry pork from the first control group was significantly lower in the comparison with the evaluations for dry meat from the second control group (C2) and the first experimental group (P ? 0.05).

MYOPATIE JATEČNÝCH KUŘAT

High-powered means of slaughter chickens production cause on certain individuals abnormal biochemical development of postmortal changes in their muscles. It consequently lead to interferences of sensory quality of the chicken meat. So called myopathies of the chicken breast meat occur in the low extent. It is typical variation in dark colouring of breast muscle. Veterinary supervision confiscates chickens embodying myopathy by reason of sensorical unacceptable dark muscle colour. Deepness of colour is evaluated by adspection of veterinary supervisors. It is tendency leading to find out objective parameters for evaluating this sensual chicken meat colour variation. Incidence of the chickens with myopathy has been evaluating for 3 years in big poultry slaughter, therewithal high-quality chickens and chickens with perspicuous myopathy have been taking out of slaughter-line. Electric conductivity values and pH values were measuring during 60 till 330 minutes post mortem in breast muscles. Aproximately 9 millions chicken was annually slaughtered and 13 thousands of them was confiscated out of the slaughter line by reason of myopathy. It amounts to 0.14 per cent of annually count of processed chickens. Myopatical chickens had significantly higher muscle pH values as compared with healthy ones. Healthy chicken muscles decreased on ultimative pH values aproximately past 3 hours post mortem. It means pH 6.03, and after 300 minutes decreased to pH 5.82. However, myopatical chickens values varied from pH 6.46 to pH 6.30. Concurrently measured values of electric conductivity significantly corellated with pH values. Whereto, it's predication of similarity chicken myopathies and dark, firm, dry (DFD) pork or turkey meat. Beyond unacceptable dark meat colour have disadvantage in poor post mortem acidifying of the meat and in consequence of microbial proteolyse. Significantly correlation between pH and electric conductivity values foreshadows on identification of myopatical chicken meat by means of conductivity measuring.

Niacin supplementation increases the number of oxidative type I fibers in skeletal muscle of growing pigs

BackgroundA recent study showed that niacin supplementation counteracts the obesity-induced muscle fiber switching from oxidative type I to glycolytic type II and increases the number of type I fibers in skeletal muscle of obese Zucker rats. These effects were likely mediated by the induction of key regulators of fiber transition, PGC-1α and PGC-1β, leading to muscle fiber switching and up-regulation of genes involved in mitochondrial fatty acid import and oxidation, citrate cycle, oxidative phosphorylation, mitochondrial biogenesis. The aim of the present study was to investigate whether niacin supplementation causes type II to type I muscle and changes the metabolic phenotype of skeletal muscles in growing pigs.Results25 male, 11 wk old crossbred pigs (Danzucht x Pietrain) with an average body weight of 32.8 ± 1.3 (mean ± SD) kg were randomly allocated to two groups of 12 (control group) and 13 pigs (niacin group) which were fed either a control diet or a diet supplemented with 750 mg niacin/kg diet. After 3 wk, the percentage number of type I fibers in three different muscles (M. longissismus dorsi, M. quadriceps femoris, M. gastrocnemius) was greater in the niacin group and the percentage number of type II fibers was lower in the niacin group than in the control group (P < 0.05). The mRNA levels of PGC-1β and genes involved in mitochondrial fatty acid catabolism (CACT, FATP1, OCTN2), citrate cycle (SDHA), oxidative phosphorylation (COX4/1, COX6A1), and thermogenesis (UCP3) in M. longissimus dorsi were greater in the niacin group than in the control group (P < 0.05).ConclusionsThe study demonstrates that niacin supplementation induces type II to type I muscle fiber switching, and thereby an oxidative metabolic phenotype of skeletal muscle in pigs. Given that oxidative muscle types tend to develop dark, firm and dry pork in response to intense physical activity and/or high psychological stress levels preslaughter, a niacin-induced change in the muscle´s fiber type distribution may influence meat quality of pigs.

Effect of feed deprivation and lairage time on carcass and meat quality traits on pigs under minimal stressful conditions

Fasting pigs at the farm prior to transport and keeping pigs in lairage before slaughter can affect carcass, gastrointestinal tract content and meat quality. The aim of the present study was to determine the effect of the on-farm fasting periods and lairage on the killing-out, carcass and meat quality. Seventy-two pigs were submitted to a 2×2 experimental design, with two on-farm fasting periods (0 or 12h) and two lairage times (0 or 12h) while handling was performed under minimal stressful ante mortem conditions. Feed intake was monitored individually, and carcass and meat quality traits were studied. On-farm fasting time increased life body weight losses during the on-farm fast period (P<0.001) and cold killing-out (P=0.01). On-farm fasting time also tended to increase skin lesions (P=0.082) and pH measured at 45min in the Semimembranosus muscle (P=0.0753). Lairage also increased body weight losses (P<0.001) and killing-out (P=0.003), and did not affect any of the meat quality traits. The following meat quality classes were also defined: (i) pale, soft and exudative, (ii) red, soft and exudative, (iii) pale, firm and exudative, (iv) red, firm and non-exudative, and (v) dark firm and dry. Their incidence was studied: no incidence of dark, firm and dry pork was observed, and loins from pigs fasted up to 12h were mainly classified as red, soft and exudative. In the present study, long feed deprivation (24–26h) did not negatively affect carcass traits and reduced the incidence of exudative meat without increasing the occurrence of dark firm and dry pork.

Invited review: Effects of lairage and slaughter conditions on animal welfare and pork quality

Besides creating a reservoir of animals aimed at maintaining the constant speed of the slaughter line, the function of lairage is to allow the animals to recover from the stress of transport and unloading. However, inadequate treatment of slaughter pigs in this stage or lack of environmental control may result in additional stress leading to economic losses due to poor animal welfare (deads-on-arrival and downers), skin damage and poor meat quality. Short and long lairage times can result in increased incidences of pale, soft, exudative and dark firm, dry pork, respectively. However, these effects are influenced by the environmental conditions and the pig genotype. Mixing unfamiliar pigs increases skin damages due to fighting, but keeping pigs in small groups or at high stocking density may limit this effect. Research is needed to identify alternative tools to the electric prod and to design a stunning chute enabling a smooth flow of pigs into the stunner.

Control System for Sausage Drying Based on On-Line NIR aw Determination

Advanced control technologies have been used to monitor and control the process of drying of dry-cured meat products. The near-infrared sensor (NIR) system provides the controller with up-to-date information on the product. A control algorithm has been written in LabVIEW and runs on a programmable automation controller (PAC), Compact FieldPoint, by National Instruments. Using the on-line information from the probes and NIR, the controller calculates and modifies air relative humidity set points to properly develop the process of pork sausage drying, which enables maintaining the required superficial water activity of dry pork sausage.

Effect of ionizing radiation on quality characteristics of vacuum-packaged normal, pale–soft–exudative, and dark–firm–dry pork

Normal, pale–soft–exudative (PSE), and dark–firm–dry (DFD) pork Longissimus dorsi muscles were vacuum-packaged, irradiated at 0, 2.5 or 4.5 kGy, and stored at 4 °C for 10 days. The pH, color and lipid oxidation of pork were determined at 0, 5 and 10 days of storage. Volatile production from pork loins was determined at Day 0 and Day 10, and sensory characteristics at Day 7 of storage. Irradiation increased the redness of vacuum-packaged normal, PSE and DFD pork. However, the 2-thiobarbituric acid reactive substances (TBARS) values of three types of pork were not influenced by irradiation and storage time. Irradiation increased the production of sulfur (S)-containing volatile compounds, such as mercaptomethane, dimethyl sulfide, carbon disulfide, methyl thioacetate, and dimethyl disulfide, as well as total volatiles in all three types of pork. Normal pork produced higher levels of total and S-containing volatile compounds than the PSE and DFD pork did. The volatiles produced by irradiation were retained in the vacuum packaging bag during storage. Although the odor preference for the three meat types of pork was not different, the panelists could distinguish irradiated meat from the non-irradiated. Industrial relevance: Several US meat companies have already started test-marketing irradiated meat products. Irradiation and the subsequent storage of pork improved the color of PSE and DFD pork, and showed generally similar effects on the production of volatiles, except that there appeared to be a lower level of S-volatiles in the PSE than in the other two samples. This indicated that irradiation can increase the utilization of low-quality pork (PSE and DFD). DFD pork, in particular, which has shorter shelf-life than the others, could benefit the most from irradiation because the shelf-life of DFD meat can be extended significantly by both the methods of vacuum packaging and irradiation.