High frequency pre-slaughter electrical stunning in ruminants and poultry for halal meat production: A review

Assessing meat quality and textural properties of broiler chickens: the impact of voltage and frequency in reversible electrical water-bath stunning

The implementation of the head-only electrical stunning procedure in poultry processing has been aimed at enhancing eating, ethical, and religious quality. However, inconsistencies in voltage and frequency standardization, along with variations in previous research outcomes, have led to numerous cases of both under-stunned and over-stunned birds. Thus, this study aimed to comprehensively evaluate the effects of varying voltages and frequencies during electrical water bath stunning on carcass quality, meat attributes, and textural properties in broiler chickens. A cohort of 240 healthy female broilers (Cobb 500, 42-days-old, 2 kg ± 0.1 kg) was meticulously selected from a commercial farm. The birds underwent exposure to different stunning voltages (2.5, 10.5, 30, and 40 V) and frequencies (50 and 300 Hz). Subsequent analyses were conducted on meat samples to assess physicochemical properties, carcass quality, and textural attributes. The findings revealed a higher incidence of petechial hemorrhage (P < 0.05) in birds stunned at 10.5 V compared to other voltage. Notably, no broken bones were recorded in birds subjected to high voltages (30 and 40 V). Low frequency (50 Hz) significantly increased the occurrence of petechial hemorrhage and simultaneously resulted in pectoralis major muscle with decreased redness (a*). Birds subjected to the 10.5 V stunning treatment exhibited a lower cooking loss percentage. Significant interactions between voltage and ageing (V × A) were observed. Birds stunned at 30 V and aged for 7 d displayed highest drip loss compared to a one-day ageing period across different voltage levels. This interaction also impacted pH values, with birds subjected to 10.5 V showing significantly lower (P < 0.05) pH at d 7 of ageing. The meat hardness was influenced by the V × A interaction, wherein birds stunned at 10.5 V exhibited lower hardness after one day of ageing compared to other voltage levels. Red wing tips, lightness (L*), adhesiveness, and resilience were also significantly impacted (P < 0.05) by the interaction between frequency and voltage. A notable 3-way interaction was observed for gumminess and chewiness (F × V × A), where the 2-way interaction between frequency and voltage (F × V) affected both parameters differently at various ageing periods. Additionally, there was a significant interaction (P < 0.05) between frequency and voltage influencing shear strength and yellowness.

Are spiritual, ethical, and eating qualities of poultry meat influenced by current and frequency during electrical water bath stunning?

With the continuous rise of Muslim and Jewish populations and their increasing preference for ritually slaughtered poultry meat, the industry is forced to redefine its existing product-centric quality standard toward a new consumer-centric dimension of quality. The new dimension is mainly attributed to ensuring animal welfare and ethical treatment (ethical quality), spiritual quality (such as halal status, cleanliness), and eating quality standards set by religion. To meet consumer quality requirements while maintaining high production performance, the industry has incorporated newer technologies that are compatible with religious regulations such as stunning methods like electrical water bath stunning. However, the introduction of new techniques such as electrical water bath stunning has been met with mixed reactions. Some religious scholars have banned the use of any stunning methods in religious slaughter, as halal status is believed to be compromised in cases where birds have been stunned to death before slaughter. Nevertheless, some studies have shown the positive side of the electrical water bath stunning procedure in terms of preserving eating, ethical, and spiritual quality. Therefore, the present study aims to critically analyze the application of various aspects of electrical water bath stunning such as current intensity and frequency on various quality attributes, namely, ethical, spiritual, and eating quality of poultry meat.

The efficacy of electrical stunning of New Zealand rock lobster (Jasus edwardsii) and freshwater crayfish (Paranephrops zealandicus) using the Crustastun™

Large numbers of decapod crustacea are farmed and harvested globally for human consumption. Growing evidence for the capacity of these animals to feel pain, and therefore to suffer, has led to increased concern for their welfare, including at slaughter. In New Zealand, decapod crustacea are protected by animal welfare legislation. There is a requirement that all farmed or commercially caught animals of these species killed for commercial purposes are first rendered insensible. The aim of this study was to evaluate the efficacy of the Crustastun™, a commercially available bench-top electrical stunner, in two commercially important New Zealand crustacean species; the rock lobster (Jasus edwardsii) and kōura (freshwater crayfish [Paranephrops zealandicus]). Animals were anaesthetised via intramuscular injection of lidocaine and instrumented to record the electrical activity of the nervous system, prior to being stunned according to the manufacturer's instructions. Stunning efficacy was determined by analysing neural activity and observing behaviour post stunning. All ten P. zealandicus and three J. edwardsii appeared to be killed outright by the stun. Of the remaining J. edwardsii, six exhibited some degree of muscle tone and/or slow unco-ordinated movements of the limbs or mouthparts after stunning, although there was no recovery of spontaneous or evoked movements. One J. edwardsii was unable to be stunned successfully, likely due to its very large size (1.76 kg). None of the successfully stunned animals showed any evidence of return of awareness in the five minutes following stunning. It was concluded that the Crustastun™ is an acceptable method for killing P. zealandicus and for stunning all but the largest J. edwardsii.

Determining the Possibilities of Reducing Visible Quality Defects in Commercial Elements of Turkey Carcasses Using an Alternative Stunning Device

The development of the quality and commercial value of poultry meat is related to the formation of visible quality defects (hemorrhages) in muscles during the first stage of production (stunning). The production of meat with an unusual appearance for the consumers affects their purchasing decisions and, consequently, the company's economics. The aim of this research was to determine the possibility of reducing visible quality defects (large and small hemorrhages) in commercial turkey carcass elements (fillet, loin, wing) using an alternative device (AD) for the electrical stunning of animals in comparison to the quality effects obtained using the conventional device (CD) in plant X. The factors differentiating the experiment were the electrical current frequency (AD: 125, 400, 800, and 1600 Hz; CD: 50 Hz) and process time (9 and 18 s). The increase in electrical current frequency used in the alternative device stunner (own construction) resulted in changing the percentage share of defective turkey meat production. The greatest reduction of minor and severe meat defects and improvement of its quality were obtained for the alternative device at f = 800 Hz and t = 9 s-considered optimal for specific industrial conditions. Extending the time of stunning turkeys to 18 s had a positive effect on visible quality defects in the evaluated commercial elements of the carcass; however, its application in practice will depend on the efficiency of the slaughter line of the plant. A comparative analysis of the results of the impact of the frequency of electric current in the alternative device and plant X on the improvement of meat quality showed a justified need to commercialize the research results and replace the device currently used in the plant with an alternative one.

Effect of halal and stunning slaughter methods on meat quality: A review

The handling and slaughtering processes for animals have a significant effect on meat quality. Islamic (halal) slaughter and many different stunning methods are used in the meat industry worldwide. The objective of the present review was to update the current literature and practices concerning halal slaughter and stunning methods, and their effects on meat quality. The present review used inductive reasoning and comparison between halal and stunning methods for the slaughtering of farm animals. Halal slaughter involves cutting the carotid arteries, jugular veins, oesophagus, and throat without stunning. Halal slaughter facilitates the draining of blood from the animal, which is necessary to produce high-quality meat with good conservation and increased shelf life. On the other hand, most stunning slaughter hinders the bleeding process in sheep and goats. The retained blood content may act as a suitable medium for the growth and multiplication of different kinds of harmful microorganisms and make badly bled meat hard to preserve. Proper halal slaughter has several advantages regarding meat quality in comparison to stunning methods, and requires greater management attention pre-, during, and post-slaughtering to maintain good welfare and the production of high-quality meat.

ELECTRONARCOSIS PROTOCOLS IN BROILER CHICKENS FOR THE HALAL MARKET

This study considered the parameters of the Halal market to evaluate different protocols for broiler electronarcosis regarding time to return of consciousness, bleeding efficiency, and carcass and meat quality. Was performed an experiment in a broiler slaughterhouse. One hundred and eighty-four 43 days old male broilers of the Cobb® strain were used. The experimental design used was completely randomized with 46 broilers for each protocol. The protocols used: 80 v and 600 Hz; 50 v and 1,000 Hz; 60 v and 1,000 Hz; 70 v and 1,000 Hz. Time to return of consciousness, bleeding efficiency, bruising, presence of broken bones in pectoral muscle, and meat quality were evaluated. Birds subjected to stunning by the 50 v / 1,000 Hz protocol showed the shortest time to return of consciousness after electronarcosis, and high incidence of breast hemorrhage. Birds subjected to the 60 v / 1,000 Hz protocol had a higher percentage of broken bones in the Pectoralis minor. The 50 v and 1,000 Hz electronarcosis protocol fits better to the halal market due to the shorter time to return of consciousness and improved bleeding efficiency. This study suggests new proposals for stunning protocols to serve the halal market.

Pros and cons of different stunning methods from a Halal perspective: a review

There has always been a debate about the acceptability of stunning methods for preparing Halal slaughtered meat. Throughout the last few decades, stunning methods have become acceptable for Halal slaughtering due to an increasing majority of Muslim countries issuing Fatwas (religious rulings) that approve of stunning methods for the Halal slaughtering of food animals. With an increasing Muslim population worldwide, Halal meat provision is important for Muslims both economically and ethically. Moreover, there have been concerns regarding traditional Halal slaughter without the use of stunning from the standpoint of the animal's welfare. This article reviews the different stunning methods available and the associated processing practices, addressing their pros and cons in the commercial production of Halal meat.

Halal food supply chains: A literature review of sustainable measures and future research directions

Introduction. Although sustainability represents a high-profile topic in supply chain management, it remains an unexplored research area for Halal food supply chains (HFSCs). Hence, to bridge this knowledge gap, we conducted a systematic literature review to identify the measures necessary for the development of sustainable HFSCs and potential research gaps at the nexus of sustainability and Halal food literature. Study objects and methods. We carefully analyzed forty (40) papers selected from leading, highly-ranked journals to answer the following research question: “What are the measures necessary for the development of sustainable Halal food supply chains?” Results and discussion. The findings revealed that the improvement of Halal processes through the implementation of quality management systems, the effectiveness of Halal labeling, and the use of technology could enhance the economic performance of HFSCs. Furthermore, HFSC’s sustainability efforts are strengthened by enhancing trust and transparency benefitting human resource skills development, promoting animal welfare issues, and increasing regulatory compliance. The implementation of environmental protection measures is a primary driving factor for environmental sustainability activities. Environmental sustainability could be fostered by a shift to the application of greening practices and the support of environmentalism in the Halal food industry. Conclusion. The findings of this study provide critical managerial implications for Halal food practitioners as they can have a summary of the previous studies and thus use it as a benchmark for introducing sustainable measures in their Halal food firms.

Pain at the Slaughterhouse in Ruminants with a Focus on the Neurobiology of Sensitisation

Simple Summary

We pose based on a fundamental science examination that events that occur around the time of slaughter have the potential to intensify the pain response, through a process called sensitisation, or an exaggerated response to painful stimuli. Health conditions which result in inflammation, injuries arising from transport and handling and exaggerated fear responses may all be present at the slaughterhouse. Whilst there is limited evidence of a direct effect of these on the processes of sensitisation in animals at slaughter, by analogy with the human neurobiology literature the connection seems plausible. In this review we outline the biology of such a response, and the rationale for suggestion of a possible linkage between events at slaughter and a heightened animal pain response.

Abstract

We pose, based on a neurobiological examination, that events that occur around the time of slaughter have the potential to intensify the pain response, through the processes of sensitisation and enhanced transmission. Sensitisation, or an enhanced response to painful stimuli, is a well-discussed phenomenon in the human medical literature, which can arise from previous injury to an area, inflammatory reactions, or previous overstimulation of the stress axes. A number of events that occur prior to arrival at, or in the slaughterhouse, may lead to presence of these factors. This includes previous on-farm pathology, injuries arising from transport and handling and lack of habituation to humans. Whilst there is limited evidence of a direct effect of these on the processes of sensitisation in animals at slaughter, by analogy with the human neurobiology literature the connection seems plausible. In this review a neurobiological approach is taken to discuss this hypothesis in the light of basic science, and extrapolations from existing literature on the slaughter of ruminants. To confirm the postulated link between events at slaughter, and processes of hypersensitisation, further dedicated study is required.

Performance, carcass and meat quality of pigs submitted to immunocastration and different feeding programs

The feed restriction of pigs aims to improve the nutrient utilization of the diet, reduce carcass fat and increase lean meat. Immunocastration is a painless, reversible technique that improves animal welfare, decreases boar taint in meat, leading to lower fat deposition and increases lean meat. This study aimed at evaluating either feeding (restricted) programs (FP) and castration categories (surgically castrated × immunocastration) in terms of pig performance, carcass traits and meat quality. Castration category and FP did not influence marbling, initial pH and drip loss in loin and ham. However, immunocastrated pigs presented lighter loins and hams with lower ultimate pH, compared to the surgically castrated pigs. The FP with lower feed volume resulted in higher ultimate pH. Immunocastrated males had a higher live weight than those surgically castrated. Also, the more the feed supply decreased, the better the feed conversion. Immunocastrates had lower carcass yields, however these pigs had their backfat thickness decreased and lean meat increased in the carcass, without affecting the loin depth.

Electrical stunning parameters: impact on the quality of turkey meat (Meleagris gallopavo)

Pre-slaughter conditions can interfere with the quality of meat. Proper stunning systems can minimize the occurrence of meat anomalies. The goal of this study was to assess the effects of electrical stunning parameters on the quality of turkey meat. Nine assays were conducted, with varying frequency, current, and voltage. The variables assessed in the assays were incidence of bruising, bleeding, blood splash and contusions, pH, color, water holding capacity, and shear force. A high incidence of bruising was observed in the breasts (25.0-57.1%) and carcasses (52.5-58.5%) of the turkeys. The pH of the turkey breasts ranged from 5.9 to 6.0 and the shear force ranged from 13.9 to 18.4 N. The frequencies had different effects on the assessed variables, leading to the formation of two groups: group 1-low frequencies (50-200 Hz) and group 2-high frequencies (633-1500 Hz). The incidence of anomalies in the turkey breast and carcasses was higher in group 1 than in group 2. The use of frequencies to stunning below 200 Hz tends to increase blood spots, fractures/contusions and bruising in turkey meat.

Broiler stunned state detection based on an improved fast region-based convolutional neural network algorithm

An improved fast region-based convolutional neural network (RCNN) algorithm is proposed to improve the accuracy and efficiency of recognizing broilers in a stunned state. The algorithm recognizes 3 stunned state conditions: insufficiently stunned, moderately stunned, and excessively stunned. Image samples of stunned broilers were collected from a slaughter line using an image acquisition platform. According to the format of PASCAL VOC (pattern analysis, statistical modeling, and computational learning visual object classes) dataset, a dataset for each broiler stunned state condition was obtained using an annotation tool to mark the chicken head and wing area in the original image. A rotation and flip data augmentation method was used to enhance the effectiveness of the datasets. Based on the principle of a residual network, a multi-layer residual module (MRM) was constructed to facilitate more detailed feature extraction. A model was then developed (entitled here Faster-RCNN+MRMnet) and used to detect broiler stunned state conditions. When applied to a reinforcing dataset containing 27,828 images of chickens in a stunned state, the identification accuracy of the model was 98.06%. This was significantly higher than both the established back propagation neural network model (90.11%) and another Faster-RCNN model (96.86%). The proposed algorithm can complete the inspection of the stunned state of more than 40,000 broilers per hour. The approach can be used for online inspection applications to increase efficiency, reduce labor and cost, and yield significant benefits for poultry processing plants.

Halal Criteria Versus Conventional Slaughter Technology

Simple Summary

While legislation can be implemented, amended or revoked according to the requirements of a given time period, this is very difficult or even impossible with religious laws due to their sanctity. Faithful Muslims believe in the sanctity of the main Islamic laws (Quran and Hadiths) because, according to them, they originated from heavenly and divine sources (God and his prophet Muhammad). The technological means of the meat industry are constantly evolving to meet the requirements of the present day and may sometimes be inconsistent with ancient religious norms. Recently, greater attention has been paid to the halal meat industry due to the increased size of the Muslim community in Europe; the opportunity of producing and exporting meat and meat products to the Islamic world; and the ease of delivery, trade and transport. The purpose of this study is to highlight some of the controversial aspects of modern technological means and the principles of the halal meat industry. The controversial aspects that this study deals with include the practices of modern slaughter (animal fasting prior to slaughter, the animal’s body position during slaughter, the location of the incision during bleeding, stunning and mechanical slaughtering). This review may contribute to raising awareness among producers and consumers and to finding means of technology compatible with halal criteria.

Abstract

The halal meat industry is today a reality in many regions of the world, including the European Union. The main religious laws in the area of halal meat production were legislated in ancient times and may be unchangeable due to their sanctity perceived by faithful Muslims, while the modern technology used in the meat industry is constantly evolving and being updated. The objective of this study is to highlight the points of controversy between the principles of halal and the technological means currently used in the meat industry. Modern slaughter practices, including animal fasting prior to slaughter, animal body position, the location of the incision during slaughter, stunning and mechanical slaughter, are reviewed. The purpose of preslaughter feed availability according to halal criteria could be to ensure greater welfare for animals, though feed withdrawal is necessary today. Although there is no clear unified opinion among the Islamic sects, reversible stunning of animals is generally accepted. A neck cut at a higher position than the conventional low cut in cattle may reduce the compromise in welfare (the onset of unconsciousness), minimise false aneurysm and be compatible with halal criteria. This study may contribute towards consideration being given to technology that is not in conflict with the religious legislation, while at the same time meeting the requirements of the modern meat industry.

Electroencephalographic and blood parameters changes in anaesthetised goats subjected to slaughter without stunning and slaughter following different electrical stunning methods

Electrical stunning is the most widely used stunning method for sheep and goats. Because low frequency head-to-back electrical stunning induces cardiac arrest, it is non-compliant with halal requirements. In addition, conventional head-only electrical stunning method can have adverse effects on carcass and meat quality. To address these issues high-frequency electrical stunning systems were developed. High frequency head-to-back removes the potential for pain and distress compared with non-stunned slaughter and does not induce cardiac arrest like low frequency head-to-back stunning making it appropriate for halal. However, this claim is yet to be proven through a comprehensive neurophysiological study. Thus, the present study examined the effects of different pre-slaughter electrical stunning methods and slaughter without stunning on electroencephalographic and blood biochemistry changes. Thirty-two male Boer crossbred bucks were distributed into four groups of eight animals each and subjected to slaughter without stunning (SWS), low frequency head-only (LFHO) and low frequency head-to-back (LFHB) or high frequency head-to-back electrical stunning (HFHB). Slaughtering of animals with or without stunning was performed under minimal anaesthesia. Based on electroencephalograph results, at slaughter, the SWS animals showed an increase in brain electrical activity, which is consistent with the presence of post slaughter noxious sensory input associated with tissue damage. Meanwhile the electroencephalograph activities decreased immediately after application of electrical stunning in all animals, suggesting that they were insensible to pain during and after the neck cut. Electrical brain activities for goats subjected to HFHB were comparable to those for LFHO and those for LFHB. The percentage of animals that exhibited severe clonic activity was significantly lower after LFHB or HFHB stunning compared with LFHO. The concentrations of catecholamines and hyperglycemia in electrically stunned goats were higher compared with those from SWS. It was observed that LFHB caused cardiac arrest in all goats whereas all HFHB goats had no cardiac arrest. High frequency head-to-back electrical stunning may be an improvement on non-stunned slaughter and has advantages for meat quality. However, stunning effectiveness after head-to-back electrical stunning with high frequencies needs to be evaluated under industrial conditions before any recommendation is given.