Meat Processing Research Articles

Mitigating COVID-19 in meat processing plants: what have we learned from cluster investigations?

Several COVID-19 outbreaks have been reported in meat processing plants in different countries. The aim of this study was to assess the environmental and socio-economic risk factors favouring the transmission of SARS-CoV-2 in meat processing plants and to describe the prevention measures implemented. Data from epidemiological investigations of COVID-19 clusters in France, the scientific literature, structured interviews and site visits were collected and summarised to investigate the main risk factors for SARS-CoV-2 infection in meat processing plants, including determinants within and outside the workplace. An increased risk of infection was identified among workers with unfavourable socio-economic status (temporary/non-permanent workers, migrants, ethnic minorities, etc.), possibly related to community activities (house-sharing, car-sharing, social activities). Working conditions (proximity between workers) and environmental factors (low temperatures and inadequate ventilation) also appear to be important risk factors. These environmental conditions are particularly prevalent in cutting and boning plants, where the majority of reported cases are concentrated. Preventive measures applied included screening for COVID-19 symptoms, testing, wearing masks, increased hygiene and sanitation, physical and temporal distancing, control of ventilation. Certain food safety hygiene measures were compatible with protecting workers from SARS-CoV-2. The hygiene culture of agri-food workers made it easier to implement preventive measures after adaptation. This study made it possible to identify the environmental and socio-economic factors conducive to the transmission of SARS-CoV-2 in meat processing plants. The knowledge gained from this work was used in simulations to understand the transmission of the virus in the plants.

Monitoring airborne pathogen transmission for enhanced safety at food processing facilities

AbstractFood manufacturing and processing are part of the nation's critical infrastructure. Due to the recent global spread of the SARS-CoV-2 virus, the potential contamination of the food chain and the resulting public health implications are of high consequence to society. The current primary food manufacturing and processing facilities already have various mechanisms such as hazard analysis and critical control point (HACCP) system in place. However, the widespread microbial infections in these facilities raise concerns that they will not only threaten the welfare of food processing workers, but also have a potentially greater consequence on the public if the food is contaminated with an infectious agent.Despite the increasingly recognised role of the environment in the spread of microbes, the effect of air properties remains poorly understood. Heating, ventilation, and air conditioning (HVAC) systems in meat processing facilities not only provide a means of transport for viruses and bacteria but may also deposit them on surfaces where they can survive for days. To maintain a stable and safe food chain supply during the pandemic, the challenges to ensure safe food supply and protect the workers' health must be quickly addressed through sustainable, safe and economic approaches. With these two imminent challenges in mind, the overall goal of this review article is to provide a comprehensive overview of the role of the environment in the impaction and resuspension of bioaerosols, focusing on airborne bacteria and viruses. The review includes the latest results of modeling the spread of microbial aerosols in the airflow and the development of preventive measures to mitigate virus contamination in the unique environment of meat processing operations. By understanding how the environmental factors and seasonality affect the infectivity and spread of airborne pathogens, mitigation measures can be designed to minimise future infections within and beyond these facilities.

Optimization of pulsed electric fields-assisted thawing process conditions and its effect on the quality of Zhijiang duck meat

Freezing storage is a common preservation method for industrialized duck meat. However, both the frozen storage and thawing processes of meat can affect meat quality. Therefore, appropriate thawing methods are crucial for maintaining good meat quality. In this study, a pulsed electric field (PEF) was used for thawing zhijiang duck meat and the freshed duck meats were used as control. Optimization of the PEF-assisted thawing process and its effect on the quality of zhijiang duck meat were analyzed. Our data showed that the shear force in the 2 kV/cm PEF-assisted thawing group was the lowest in PEF-assisted thawing groups. The color of zhijiang duck meat in the 2 kV/cm PEF-assisted thawing group was optimal. The 2 kV/cm PEF-assisted thawing could improve the texture characteristics of zhijiang duck meat and enhance water holding capacity of zhijiang duck meat. PEF-assisted thawing could better maintain the microstructure of zhijiang duck meat. Our data showed that if the intensity or duration of PEF treatment is too high, the quality of duck meat will actually decrease. Therefore, appropriate parameters should be selected in practical applications, which will provide a reference for the application of PEF-assisted thawing on the market.

Reduction of Nitrate and Acrylamide in Heat-processed Meats using treatment with Lactobacillus Casei and Plant Extracts

Background: Food security has always been a concern in the multi-factorial systems analysis of health and wellbeing. The presence of nitrate and acrylamides in cooked meat leads to negative health outcomes. Objective: This study aimed to reduce nitrate and acrylamide content in different kinds of meats (chicken, turkey, lamb, beef, quail, and fish) using some plant extracts and lactobacillus treatment. Methods: The extracts were prepared from Coriandrum sativum, Nigella sativa, and Thymus leaves and stem. The used bacteria was Lactobacillus casei subsp. rhamnosus LCR6013. Acrylamide and nitrate were measured by liquid chromatography and colorimetric spectrophotometry methods Results: The results showed that both bacterial treatment and plant extracts could reduce the amount of acrylamide and nitrate. The most reduction in the amount of acrylamide and nitrate was obtained by adding Thymus and Nigella sativa extracts, followed by coriander extract and bacterial inoculum. Also, bacterial treatment was more effective for nitrate reduction than acrylamide. Conclusion: It was concluded that the plant extracts and bacterial treatment are appropriate solutions to reduce the amount of acrylamide and nitrate during the baking process of meat.

Application of Hazard Analysis Critical Control Point (HACCP) principles to beef mortadella production

A mortadella is a cooked sausage made from raw pork, beef, chicken or lamb. It is popular in Jordan and neighboring countries for its taste, texture, nutritional value and ease of inclusion in sandwiches. The product is sold in plastic packaging, in circular rolls or vacuum packed. Although it poses no serious threat to human health, the heat can be dangerous if used improperly. A HACCP system is used to manage the production process, with a focus on quality control (CCP) throughout the manufacturing phase. Safety risks are identified at all stages of production, from raw materials to storage and distribution. Foodborne illnesses are primarily caused by pathogenic microorganisms, and these raw materials include pathogenic plant cells, Bacillus cereus, Clostridium botulinum and Clostridium perfringens that survive after cooking and contamination detected after monitoring. Post-manufacturing controls are performed through Good Manufacturing Practices (GMPs). The objectives of the study were to identify potential hazards associated with the production of beef mortadella, determine the CCPs to be implemented, develop a monitoring plan and establish corrective action on a case-by-case basis. The HACCP plan was developed in collaboration with local stakeholders and follows a process flow diagram to identify potential hazards and preventive measures. The system includes the steps for obtaining and storing the ingredients, preparing the meat, adding non-meat ingredients, and transferring the raw mixture to an incubator. The meat is weighed and filled with the mixture to improve cleanliness and avoid excess nitrite. The storage time between incubation and cooking is controlled to allow bacteria to multiply. To kill plant pathogens and reduce the total number of microorganisms, the product is cooked in a steam oven at 75°C for 5 minutes. The aim of the cooking process is to reduce microbial growth before lethal temperatures have been reached and uniform heating of the product has been ensured. Cooking suitability is checked by thermographic records and visual inspection of the cooked product. The plan also includes personnel in charge of every stage of production, ensuring a clean and hygienic environment. Key words: HACCP, Mortadella, meat processing, hygiene control, food safety

Devising a technology for obtaining glued sausage casings from intestinal raw materials using electrophoresis

The object of research is the technique for obtaining glued sausage casings, in which adhesive related structures and electrophoresis for tanning are used to glue the layers of intestinal raw materials. Devising a technique for gluing sausage casings from intestinal raw materials with the use of adhesive related structures by stitching by tanning, via intensified electrophoresis, has been substantiated. The technology of glued sausage casings from intestinal raw materials, which are classified as unclaimed residues and waste, has been proposed. The technology differs from known similar technologies by applying a technique for gluing intestinal membranes using an adhesive related construct and electrophoresis during tanning. The devised gluing technique and the device for its implementation make it possible to avoid violation of the integrity of the raw material, are universal in relation to it, and are easy to operate. The rational parameters of electrophoresis, which is used to accelerate the tanning process of the place of gluing of the layers of the intestinal membranes using an adhesive related construct, have been determined. The potential difference between the electrodes and the duration of exposure of the gluing site for gluing the original intestinal raw materials: pork belly, lamb belly, beef belly were determined. At a potential difference of 100 V, the duration of exposure of the gluing site for pork and lamb bellies is 17 minutes, and for beef bellies − 20 minutes. It is noted that the results differ in the duration of exposure of the gluing site, which is probably due to the thickness of the layer of the raw material. The proposed technology would contribute to improving the efficiency of the technology of glued sausage casings from intestinal raw materials and could be used at enterprises for the processing of agricultural products and the meat processing industry

Effect of Poor Post-Slaughter Handling on Physicochemical and Microbial Quality of Fresh Broiler in Bangladesh

The slaughtering method and post-handling play an important role in meat processing. Countries followed different slaughtering methods, post-handling, and preservation techniques for post-slaughtered meat. Stress-oriented slaughtering, unhygienic handling, processing, and improper preservation are triggering factors of rapid oxidation and microbial proliferation in meat during storage. Bangladesh is a Muslim-oriented country but many vendors do not follow the halal slaughtering, and handling of meat in an unhygienic way due to a lack of food safety knowledge. Thus, the study aims to assess the effect of poor post-slaughtering handling practices on the physiochemical properties which include moisture, ash, protein content, fat content, drip loss, cooking loss, water holding capacity, pH, fat oxidation, color, heme iron, mineral content, and microbial qualities of fresh samples by total plate count during 0 days, 15 days and 30 days frozen storage at -18ºC. The live broiler was purchased randomly and slaughtered instantly from different slaughter shops in Jashore City, Bangladesh. The laboratory analysis was performed following the standard method of meat sample analysis. The outcome of this study revealed that heme iron content, minerals like Ca, Fe, Zn, and lightness values decreased significantly (p < 0.05) during 30 days of storage at -18 ºC. Post-handling had no significant effect (p > 0.05) on protein and ash content at 0 and 15 days of storage but slowly decreased with increasing storage time. The continuous increase in pH, cooking loss, and TBARS value indicate rises in lipid oxidation noticed in all samples, especially during 16-30 days of frozen storage (p < 0.05). The total viable count significantly raised (p < 0.05) and reached the highest value of 7.27 log10 CFU/g and 7.44 log10 CFU/g respectively after 15 days and 30 days of frozen storage compared to fresh condition. Bacteriologically meat samples were of very poor quality during storage compared to fresh ones.

Deer oil improves ulcerative colitis induced by DSS in mice by regulating the intestinal microbiota and SCFAs metabolism and modulating NF-κB and Nrf2 signaling pathways.

Deer oil (DO), a byproduct of deer meat processing, possesses high nutritional value. This study aims to evaluate the protective effects of DO on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice and to explore its potential mechanisms of action. DO was found to inhibit weight loss and colon shortening in colitis mice, significantly reduce disease activity index scores, and notably enhance the levels of tight junction proteins in colon tissues, thus improving intestinal barrier function. ELISA results indicated that DO markedly alleviated the mice's oxidative stress and inflammatory responses. Western blot analysis further demonstrated that DO significantly inhibited the phosphorylation of NF-κB while up-regulating the expression levels of Nrf2 and HO-1 proteins. Additionally, DO increased the abundance of beneficial bacteria such as Odoribacter, Blautia, and Muribaculum, reduced the abundance of harmful bacteria such as Bacteroides, Helicobacter, and Escherichia-Shigella, and promoted the production of short-chain fatty acids. Our study provides the first evidence that DO can effectively improve DSS-induced UC in mice. The underlying mechanisms may involve maintaining intestinal barrier function, inhibiting inflammation, alleviating oxidative stress, and modulation of gut microbiota. These findings offer valuable insights for developing DO as an adjunct treatment for UC and as a functional food. © 2024 Society of Chemical Industry.

Development of the Design of Plate with Variable Diameters of Holes and Its Impact on Meat-Grinding Quality and Efficiency

Meat-grinder plates are critical for efficiently processing meat, significantly influencing the grinding process. This study aimed to develop a meat-grinder plate with variable diameter holes and assess its impact on ground meat quality and processing efficiency. Various meat types (beef, horse meat, mutton, chicken, and pork) were processed using both plate designs: a control plate with a constant hole diameter of 12 mm and a developed plate with featured holes increasing in diameter from periphery to center (8 mm–12 mm–16 mm). The results demonstrate that the developed plate significantly improves the WBC of minced meat, with notable increases in beef (58.3% vs. 57.7%), horse meat (61.8% vs. 56.2%), chicken (51.0% vs. 49.1%), and pork (46.1% vs. 43.6%), indicating a more homogeneous particle size distribution. Yield stress, a critical factor influencing the rheological properties of minced meat, also showed substantial improvements, particularly in poultry (18.9% increase) and pork (31.3% increase). The variable hole design produced a higher proportion of intermediate-sized particles, contributing to a more cohesive texture and potentially enhancing the binding properties of processed meat products. Theoretical calculations based on the Hagen–Poiseuille equation and empirical data confirmed that the new plate design increases the grinder’s productivity by 50%, with average throughput rising from 150 kg/h to 225 kg/h. Additionally, the developed plate reduced power consumption by up to 7.3%, particularly in horse meat processing, highlighting its cost effectiveness for industrial applications. These findings suggest that the variable diameter hole plate design offers substantial improvements in ground meat quality and processing efficiency, with potential implications for industrial meat-processing operations.

Meat products in human nutrition and health – About hazards and risks

Meat processing has a long history and involves a wide and ever-increasing range of chemical and physical processes, resulting in a heterogeneous food category with a wide variability in nutritional value. Despite the known benefits of meat consumption, observational epidemiological studies have shown associations between consumption of red and processed meat - but not white meat - and several non-communicable diseases, with higher relative risks for processed meat compared to unprocessed red meat. This has led global and regional nutrition and health organisations to recommend reducing consumption of unprocessed red meat and avoiding processed meat. A plethora of potentially implicated hazardous compounds present in meat or formed during processing or gastrointestinal digestion have been reported in the literature. However, our mechanistic understanding of the impact of meat consumption on human health is still very incomplete and is complicated by the simultaneous occurrence of multiple hazards and interactions with other food compounds and host factors. This narrative review briefly discusses hazards, risks and their assessment in the context of dietary guidelines. It is argued that more mechanistic studies of the interactive effects of meat products with other foods and food compounds in different dietary contexts are needed to refine and increase the evidence base for dietary guidelines. Importantly, the great diversity in the composition and degree of processing of processed meats should be better understood in terms of their impact on human health in order to develop a more nuanced approach to dietary guidelines for this food category.

A lipidomic and volatilomic approach to map the lipid profile and related volatile compounds in roasted quail meat using circulating non-fried roast technology

Lipids play a significant role in aroma formation. However, lipid variations and their impact on aroma during the processing of quail meat remain unknown. Therefore, a comprehensive analysis of lipids and aroma compounds was conducted in circulating non-fried roasted quail meat. Nineteen odorants were identified as key aroma compounds in the roasted quail meat at 40 min with OAVs of >1. The concentrations of most key odorants significantly increased in circulating non-fried roasted (CNR) quail meat within the first 30 min of roasting, reaching maximum values at 40 min. Phospholipids, neutral lipids, and sphingolipids emerged as potential markers for distinguishing different samples. Neutral lipids had the highest peak areas and significantly contributed to the aroma retention. Phospholipids and neutral lipids with unsaturated fatty acids, particularly C18 acyl groups, played a crucial role in aroma formation. This study provides valuable insights into the role of lipids in determining aroma quality.

Effects of using pomegranate peel, beet leaf, and broccoli flower extracts on oxidative stability and physicochemical properties of cooked ground beef during refrigerated storage.

Plant extracts gained attention in the meat industry for their role in preventing microbial growth and oxidative deterioration. Antioxidant efficiency of various ratios (0.125, 0.25, 0.5, and 1%) of ethanolic or methanolic pomegranate peel (PP), beet leaf (BL), and broccoli flower (BF) extracts on cooked ground beef was investigated during refrigerated storage. Thiobarbituric acid reactive substances (TBARS), lipid hydroperoxide (LPO), p-anisidine, cooking loss (CL), pH, and color analysis were performed. Results revealed that CL increased (p < .05) with 0.5 and 1% PE or 1% BF extracts, whereas no CL change was observed in other extract applications. Although using 0.5% and 1% of ethanolic or methanolic PP extracts caused lower pH than control (p < .05), no pH difference was found among other treatments. L* values were not affected by extract applications, whereas a* decreased and increased with PP and BL extract addition, respectively (p < .05). Meantime, a* values decreased and b* values increased by elevation in extract ratio (p < .05). In terms of solvent impact, methanolic PP and ethanolic BL extracts caused higher b* (p < .05), whereas no difference in b* was obtained between ethanolic or methanolic BL extracts. TBARS, LPO, and p-anisidine analysis revealed that the highest lipid oxidation was obtained in control (p < .05). PP extract treatments exhibited the lowest lipid oxidation (p < .05). Lipid oxidation gradually increased in control and all extract-incorporated samples during storage (p < .05). In extract-incorporated samples, lipid oxidation decreased with increasing the extract ratio (p < .05). Lipid oxidation was inhibited more by all incorporation ratios for each tested extract compared to control (p < .05). Moreover, using 0.125% PP, 0.5% BL, or 1% BF extracts was more effective in lipid oxidation inhibition than BHT (p < .05). It may be concluded that PP, BL, and BF extracts may be utilized by the meat processors to achieve prolonged shelf life and improved quality features.

Effect of precursor amino acids for carnosine synthesis on breast fiber microstructures and myofiber differentiation-related gene expression in slow-growing chicken.

: The effects of carnosine synthesis on the structural and microstructural determinants of meat quality have not been studied to date. Therefore, this study aimed to investigate the effect of supplementation with carnosine synthesis precursors on the characteristics and microstructure of breast muscle fibers in slow-growing Korat chickens (KR). : Slow-growing KR were fed a non-supplemented commercial diet (control group) or a commercial diet supplemented with 1.0% β-alanine, 0.5% L-histidine, or a combination of both 1.0% β-alanine and 0.5% L-histidine. At 10 weeks, KR were slaughtered, and the breast muscle was collected. Samples were fixed and extracted to study the microstructure, fat level, and porosity of the meat using X-ray and scanning electron microscopy, and real-time polymerase chain reaction was performed to analyze the expression of genes related to myofiber differentiation. : L-histidine supplementation significantly altered myofiber diameter and muscle fiber density and compactness by regulating muscle fiber-type differentiation via carnosine synthase (CARNS1) and myocyte enhancer factor 2C (MEF2C) expression, as well as myogenic differentiation antigen (MyoD) and myogenic regulatory factor 5 (Myf5) expression. While excess L-histidine potentially stimulated CARNS1 to modify muscle fiber arrangement and tenderness in breast meat, dietary β-alanine supplementation alone or in combination with L-histidine supplementation induced a relatively less remarkable but not significant (p<0.05) effect on the breast meat characteristics studied. : Interestingly, the combination of β-alanine and L-histidine supplementation had no effect on meat microstructure, meat porosity, and fat content in comparison with the control group. Thus, this combination had the best selectivity for improving meat quality. However, further studies are required to clarify the effects of carnosine levels on meat processing.

Kinetics, thermodynamics, and optimization analyses of lipid extraction from discarded beef tallow for bioenergy production

ABSTRACT The wide expansion of the meat industry generated tremendous amounts of animal-based waste. Discarded beef tallow (DBT) is one of those prevalent lipid-rich wastes disposed of by slaughterhouses, meat processing units, and tanneries. The current study utilized the advanced technology of supercritical CO2 (SC-CO2) to extract lipid content from DBT for biodiesel production through transesterification. The effects of SC-CO2 parameters on the extraction rate were investigated over ranges of (32–80°C) for temperature, (10–50 MPa) for pressure, and (15–150 min) for treatment time. Using response surface methodology (RSM), both processes of SC-CO2 and transesterification were optimized. The highest extraction rate was 86.10%, obtained at the experimental conditions of 60°C for temperature, 30 MPa for pressure, and 120 min for treatment time. For the transesterification, the maximum yield of biodiesel was 95.15%, obtained at the reaction conditions of 1:7.5, 1.16 wt%, 58°C, and 72 min for lipid to methanol molar ratio, catalyst ratio, temperature, and time, respectively. The outcomes of the kinetic and thermodynamic analyses showed that the SC-CO2 extraction was an endothermal, unspontaneous, and temperature-dependent process. The characteristics of the synthesized biodiesel largely comply with the ASTM D6751 and EN 14,214 standards. The findings of the current study confirm the viability of SC-CO2 to extract lipids from DBT as a low-cost feedstock for biodiesel production.

Raman Spectroscopy for the Differentiation of Muscles and Tissues in Meat Using Chicken as a Model System

ABSTRACTThe application of Raman spectroscopy in the meat processing industry as a quality assurance is dependent on its ability to differentiate tissues from the animal. Meat is commercialised as different cuts with variations in quality and financial value. Whilst it is possible to conduct some analysis on meat quality, there are high costs and time involved. The meat processing industry could benefit from rapid methods for characterising meat quality for large quantities. This study demonstrates the ability of combining Raman spectroscopy with chemometrics to discriminate tissues in a chicken carcass. All spectra from the different tissues were analysed by applying chemometrics. The principal component analysis (PCA) and discriminant function analysis (DFA) showed successful classification of different muscles and tissues.

Gene emrC Associated with Resistance to Quaternary Ammonium Compounds Is Common among Listeria monocytogenes from Meat Products and Meat Processing Plants in Poland.

(1) Background: L. monocytogenes is a food pathogen of great importance, characterized by a high mortality rate. Quaternary ammonium compounds (QACs), such as benzalkonium chloride (BC), are often used as disinfectants in food processing facilities. The effectiveness of disinfection procedures is crucial to food safety. (2) Methods: A collection of 153 isolates of L. monocytogenes from meat processing industry was analyzed for their sensitivity to BC using the agar diffusion method. Genes of interest were detected with PCR. (3) Results: Genes emrC, bcrABC, and qacH were found in 64 (41.8%), 6 (3.9%), and 1 isolate (0.7%), respectively, and 79 isolates (51.6%) were classified as having reduced sensitivity to BC. A strong correlation between carrying QACs resistance-related genes and phenotype was found (p-value < 0.0001). Among 51 isolates originating from bacon (collected over 13 months), 48 had the emrC gene, which could explain their persistent presence in a processing facility. Isolates with the ilsA gene (from LIPI-3) were significantly (p-value 0.006) less likely to carry QACs resistance-related genes. (4) Conclusions: Reduced sensitivity to QACs is common among L. monocytogenes from the meat processing industry. Persistent presence of these bacteria in a processing facility is presumably caused by emrC-induced QACs resistance.

Benzotriazoles and bisphenols in wastewater from the food processing industry and the quantitative changes during mechanical/biochemical treatment processes

Benzotriazoles (BTRs) and bisphenols (BPs), categorized as contaminants of emerging concern (CECs), pose significant risks to human health and ecosystems due to their endocrine-disrupting properties and environmental persistence. This study investigates the occurrence and behavior of nine BTRs and ten BPs in wastewater generated in a large-scale meat processing plant, evaluating the effectiveness of a modern mechanical-biological industrial on-site treatment plant in removing these contaminants, and based on the concentration levels from eleven sampling points at different stages of the treatment process. The method used to determine these micropollutants' concentration was ultrasound-assisted emulsification-microextraction for analytes isolation and gas chromatography–mass spectrometry for detection (USAEME-GC/MS). The results indicate that the rigorous quality control processes in the meat processing facility effectively limit the presence of these micropollutants, especially concerning BPs, which are absent or below detection limits in raw wastewater. While the concentrations of some of these micropollutants increased at different points in the treatment process, these values were relatively low, typically below one microgram per liter. Among the compounds analyzed, the only one present after completing the treatment was 5Cl-BTR (maximum concentration: 3007 ng/L), and these contamination levels are around seven times lower than the reference value associated with non-cancer health risk for drinking water. This study contributes to understanding these CECs in industrial wastewater and highlights the importance of effective treatment systems for environmental protection.

Comparative analysis of Salmonella contamination in pork slaughtering facilities: Implications for food safety

Salmonella is a major cause of global gastroenteritis, with pig-based products being significant sources. The Hazard Analysis Critical Control Points (HACCP) standard ensures food safety by identifying Salmonella contamination dynamics and improving control strategies. A study in Thailand found that pork in HACCP-certified slaughterhouses had significantly reduced Salmonella contamination and antimicrobial resistance (AMR) compared to in non-HACCP facilities. However, both types of slaughterhouses still experience Salmonella contamination during the slaughtering process, with limited information available on contamination sources and critical steps. The current study compared Salmonella distribution and AMR profiles in two Thai pig slaughterhouses, one of which implemented HACCP. A total of 570 samples, including feces, carcass swabs, and environmental samples, were cultured for Salmonella and investigated for AMR. The overall prevalence was 24.7%, being significantly lower at the HACCP-compliant slaughterhouse 1 (S1, 13.7%) compared to the non-compliant slaughterhouse 2 (S2, 41.2%) (P = 0.03). Slaughterhouse-specific Salmonella prevalence varied across slaughtering steps, with S2 showing high contamination rates in carcasses post-final washing, persisting until post-cutting. Additionally, specific strains were found in various locations, including feces, carcasses, workers' hands, cutting boards, and knives before and during operations. Conversely, carcasses post-final washing in S1 had the lowest contamination. Real-Time PCR identified higher Salmonella contamination and a greater copy number in S2-cutting carcasses compared to in S1. Overall, 42.6% of isolates were multidrug-resistant, showing strong resistance to ampicillin and tetracycline, while 8.51% produced extended-spectrum beta-lactamase (ESBL). It is evident that continuous monitoring and control measures are crucial to mitigate contamination and antibiotic resistance in foodborne pathogens such as Salmonella. The current study confirms that adherence to HACCP in slaughterhouses significantly reduces Salmonella in pork products. However, contamination levels rose notably post-cutting in both HACCP and non-HACCP facilities, with equipment, other carcasses, and workers' hands acting as sources of contamination. Rigorous monitoring during cutting processes is essential to identify and mitigate contamination sources, thereby improving food safety in meat processing facilities.

Full-scale study on high-rate low-temperature anaerobic digestion of agro-food wastewater: process performances and microbial community.

The fast-growing global population has led to a substantial increase in food production, which generates large volumes of wastewater during the process. Despite most industrial wastewater being discharged at lower ambient temperatures (<20 °C), majority of the high-rate anaerobic reactors are operated at mesophilic temperatures (>30 °C). High-rate low-temperature anaerobic digestion (LtAD) has proven successful in treating industrial wastewater both at laboratory and pilot scales, boasting efficient organic removal and biogas production. In this study, we demonstrated the feasibility of two full-scale high-rate LtAD bioreactors treating meat processing and dairy wastewater, and the microbial communities in both reactors were examined. Both reactors exhibited rapid start-up, achieving considerable chemical oxygen demand (COD) removal efficiencies (total COD removal >80%) and generating high-quality biogas (CH4% in biogas >75%). Long-term operations (6-12 months) underscored the robustness of LtAD bioreactors even during winter periods (average temperature <12 °C), as evidenced by sustained high COD removal rates (total COD removal >80%). The stable performance was underpinned by a resilient microbial community comprising active acetoclastic methanogens, hydrolytic, and fermentative bacteria. These findings underscore the feasibility of high-rate low-temperature anaerobic wastewater treatment, offering promising solutions to the zero-emission wastewater treatment challenge.

Enhancement of pork marinating efficiency through pulsed electric field pretreatment: Integration of parameter optimization, kinetic modeling and quality characteristics

Marination is an important part of meat processing, the disadvantage is that the process of marinating is slow and prone to losing nutrients. In this study, pork tenderloins were pretreated with pulsed electric field (PEF) before being immersed in the marinade at 4 °C. The aim was to investigate the effect of PEF pretreatment (PEFP) on the marination process, specifically mass transfer and the quality of the pork. Additionally, the response surface method (RSM) was employed to explore the optimal conditions for PEFP. Results showed that under the best condition (2 kV/cm, 141.2 Hz and 2.3% duty cycle), the NaCl content of pork cured for 6 h reached 3.31%, which could effectively shorten the marinating time of pork (up to 40%). After marinating for 6 h with PEFP, the weight, moisture, and salt changes increased significantly. The effective diffusion coefficient (De) was raised to 1.71 × 10−10 (PEFP) from 1.36 × 10−10 (control) and the kinetic model of mass transfer over time has good linear correlation. The scanning electron microscopy (SEM) results indicate that PEFP altered the muscle fibre structure of pork to some extent, resulting in loosely arranged muscle fibre bundles. The total bacterial colony count results showed that PEFP had a good sterilization effect on microorganisms in pork. Furthermore, PEFP does not alter the colour or pH of marinated pork while improving its tenderness. These results showed that PEFP could effectively promote salt diffusion to shorten marinating time and improve meat tenderness.