Meat Safety Research Articles

A One Health Perspective on Camel Meat Hygiene and Zoonoses: Insights from a Decade of Research in the Middle East.

The purpose of this review was to investigatethe microbial and chemical safety of camel meat and the zoonotic diseases associated with camels in the Middle East over the past decade, emphasizing the crucial role of a One Health approach. By systematically analyzing recent studies (in the past decade, from 2014), we assessed pathogen prevalence, contamination with heavy metals and pesticide residues, and the impact of zoonotic diseases like Middle East respiratory syndrome coronavirus (MERS-CoV). The findings revealed significant variability in pathogen prevalence, with the frequent detection of traditional foodborne pathogens (e.g., Salmonella and E. coli O157), as well as antibiotic-resistant strains like methicillin-resistant and vancomycin-resistant Staphylococcus aureus and extended-spectrum β-lactamase (ESBL)-producing E. coli, underscoring the need for stringent antibiotic use policies and robust food safety measures. Additionally, the review highlighted substantial contamination of camel meat with heavy metals and pesticide residues, posing significant public health concerns that necessitate stringent regulatory measures and regular monitoring. The persistent occurrence of zoonotic diseases, particularly MERS-CoV, along with other threats like trypanosomiasis, brucellosis, and Clostridium perfringens, emphasizes the importance of strengthening ongoing surveillance. Enhancing investment in diagnostic infrastructures, training programs, and planning capabilities is crucial to address these issues at the camel-human interface in the Middle East. Adopting a One Health perspective is vital to ensuring the safety and quality of camel meat and managing zoonotic risks effectively to ultimately safeguard public health and promote sustainable livestock practices.

Use of Essential oils as potential antimicrobial agents in meat preservation

The Producers and the manufacturers have been challenged by the increasing demand for the safe and high-quality meat and meat products over the past few decades. Particularly, the recent demand for minimally the processed, the easily prepared, and the ready-to-eat meat products combined with the novel concepts of all-natural and clean-label has rapidly increased. These products may contain natural or organic ingredients without artificial preservatives that do not trigger the common food allergies or the sensitivities. The meat and the meat products are highly prone to microbial contamination since they are rich in essential nutrients and perishable. This is further accelerated by some intrinsic factors including pH and water activity of the fresh meat. In general, the freshest meat has a water activity value higher than 0.85, and its pH value falls within the favorable pH range for spoilage bacteria of the meat. Hence, deterioration in quality and potential public health issues is common if these products are not properly handled and preserved. The significant spoilage of the meat and the meat products occurs every year at different levels of the production chain including the preparation, the storage, and the distribution. Besides the lipid oxidation and the autolytic enzymatic spoilage, the microbial spoilage plays a significant role in this deterioration process leading to a substantial economic and environmental impact.

Deep Learning-Based Automated Cell Detection-Facilitated Meat Quality Evaluation.

Meat consumption is increasing globally. The safety and quality of meat are considered important issues for human health. During evaluations of meat quality and freshness, microbiological parameters are often analyzed. Counts of indicator cells can provide important references for meat quality. In order to eliminate the error of manual operation and improve detection efficiency, this paper proposed a Convolutional Neural Network (CNN) with a backbone called Detect-Cells-Rapidly-Net (DCRNet), which can identify and count stained cells automatically. The DCRNet replaces the single channel of residual blocks with the aggregated residual blocks to learn more features with fewer parameters. The DCRNet combines the deformable convolution network to fit flexible shapes of stained animal cells. The proposed CNN with DCRNet is self-adaptive to different resolutions of images. The experimental results indicate that the proposed CNN with DCRNet achieves an Average Precision of 81.2% and is better than traditional neural networks for this task. The difference between the results of the proposed method and manual counting is less than 0.5% of the total number of cells. The results indicate that DCRNet is a promising solution for cell detection and can be equipped in future meat quality monitoring systems.

Modern methods of raw meat processing to reduce microbial contamination

There are various methods to preserve the quality and extend the expiration date of food products. Raw meat from different animal species is a highly perishable product. The relevance of this research is driven by the need to summarise contemporary knowledge on approaches and techniques aimed at extending the storage duration of safe and high-quality meat, alongside their scientific justification. This article focused on finding means to reduce bacterial contamination, as microorganisms are the primary cause of meat spoilage. This study aimed to identify the most promising and optimal methods for extending the freshness of raw meat. To conduct the analysis, information from scientific primary sources, and electronic resources was used, and the results of experimental data on the application of scientifically based safe approaches were studied. A review of the main methods and measures aimed at extending the storage period of raw meat was carried out. The advantages and disadvantages of various methods of raw meat processing that have a bactericidal or bacteriostatic effect on various, including pathogenic, microorganisms that not only cause meat spoilage but can also be a danger to the potential consumer were established. Various traditional, novel, and innovative methods are currently employed in meat processing. Given the advancements in science and technology, a comprehensive approach to raw meat processing is emerging as the most promising. After analysing the research findings of numerous scientists, it has been concluded that biological technologies utilising lactic acid bacteria, combined with traditional physical methods such as refrigeration, offer the most optimal solution. This approach preserves the freshness of meat while minimising the impact on organoleptic properties, provided that temperature regimes and processing technologies involving cultures of lactic acid microorganisms are adhered to. The practical significance of this study lies in identifying the most promising directions for further research and improving existing safe antimicrobial treatments, particularly through the use of various strains of lactic acid starters. Their practical application will enable the preservation of meat freshness and extend its storage life

Implementation of Meat Inspection Code (Republic Act No. 10536) and Challenges Encountered by Butchers and Meat Inspectors in Calamba City

Implementation of the Meat Inspection Code and Compliance with Food Safety are two important factors required to meet the quality of fresh and safe meat produce and satisfy the consumers' desire to serve this fresh meat at their dining table. This has been a long-time struggle for the City Veterinary-Slaughterhouse Management Division since no system has been implemented. The authority whose function is to safeguard the cleanliness and safeness of these produce and maintain the quality of food animal that consumers expect every day for their families. This discussed the problems and concerns that could potentially obstruct achieving the goal of client satisfaction and retention, as well as the relationships between the level of implementation of the meat inspection code and the degree of seriousness of the challenges faced by the butchers and meat inspectors. A researcher-made questionnaire was utilized in this study. This was used to randomly gather surveys from 64 respondents of butchers and meat inspectors. The Mean, Pearson Product-Moment Correlation, and Four-Point Likert Scale were used to analyze and assess the model. Based on the findings, there was a slight but statistically significant positive correlation between the degree of implementation and the severity of the difficulties faced. Additionally, the study suggested a course of action to create and enhance new methods to support the current program and modernize the system, which will help enhance the quality and condition of meat produced at a slaughterhouse that has received accreditation.

Effects of in-package cold plasma treatment on poultry breast meat packaged in high CO2 atmosphere

High CO2 in packages significantly extends microbiological shelf life of poultry meat. Cold plasma is an emerging antimicrobial treatment, which generates various reactive gas species and inactivates microbials effectively. The objective of this study was to explore the potential effects of combining high CO2 package and in-package cold plasma (IPCP) treatments on the quality and safety of raw chicken breast meat. Non-inoculated samples and samples inoculated with Campylobacter jejuni and Salmonella Typhimurium were packaged in 0, 30, 70, or 100% CO2 (with make-up gas N2) and treated with IPCP at 70 kV for 3 min. Ozone formation, microbial counts, drip loss, pH, and color were measured. There was no interaction effect between high CO2 package and IPCP on microbial counts, drip loss, and color measurements. IPCP reduced spoilage microbial growth by 0.43 log (from 7.00 log to 6.57 log, P = 0.033) and C. jejuni populations by 0.67 log (from 4.82 log to 4.15 log, P < 0.001) on meat surface but did not affect S. Typhimurium (P = 0.206). Increased CO2 in packages had more effect on spoilage microbial growth (more than 1.5 log from 8.08 log to 6.35 log, P < 0.001) and S. Typhimurium populations (more than 0.5 log from 4.94 log to 4.39 log, P = 0.004) than IPCP but did not affect C. jejuni (P = 0.163). IPCP resulted in increases in changes in L* by 1.67 units (0.70 versus 2.37, P = 0.016) and a* values by 0.56 units (0.73 versus 1.29, P < 0.001) and decreases in b* values by 0.91 units (0.46 versus -0.45, P = 0.015). High CO2 levels caused increases in changes in L* values by 4.35 units (-0.82 versus 3.53, P < 0.001) with no effects on a* and b* values (P > 0.05). Data demonstrate that there are no combined effects by high CO2 package and IPCP on meat quality and safety of raw chicken breast meat under our experimental conditions. Either high CO2 package or IPCP can retain microbial quality and safety, even though they may cause changes in appearance of stored chicken breast meat.

Effect of VP, MAP and combined packaging systems on the physicochemical properties and microbiological status of veal from unweaned calves

The packaging system is one of the factors influencing the preservation of the nutritional value, microbiological safety, and sensory attributes of meat. The study investigated changes in physicochemical and microbiological properties taking place during 15-day refrigerated storage of two calf muscles, the longissimus lumborum (LL) and semitendinosus (ST), packaged in three systems, respectively, vacuum packing (VP), modified atmosphere packaging (MAP, 80% O2 + 20% CO2), and a combined system (VP + MAP, 8 d in VP followed by 7 d in MAP). LL and ST stored in VP had significantly lower levels of lipid oxidation, higher α-tocopherol content, and higher instrumentally measured tenderness in comparison with the samples stored in MAP. On the other hand, the MAP samples had lower purge loss at 5 and 15 days, a higher proportion of oxymyoglobin up to 10 days of storage, and a better microbiological status. Calf muscle samples stored in the VP + MAP system had intermediate values for TBARS and α-tocopherol content and at the same time were the most tender and had the lowest counts of Pseudomonas and Enterobacteriaceae bacteria at 15 days. All packaging systems ensured relatively good quality of veal characteristics up to the last day of storage. However, for MAP at 15 days of storage, unfavourable changes in colour (a high level of metmyoglobin and a decrease in oxymyoglobin, redness and R630/580 ratio) and in the lipid fraction (a high TBARS value and a significant decrease in α-tocopherol content) were observed.

Meat quality and safety issues during high temperatures and cutting-edge technologies to mitigate the scenario.

Climate change, driven by the natural process of global warming, is a worldwide issue of significant concern because of its adverse effects on livestock output. The increasing trend of environmental temperature surging has drastically affected meat production and meat product quality, hence result in economic losses for the worldwide livestock business. Due to the increasing greenhouse gas emissions, the situation would get prolonged, and heat exposure-related stress is expected to worsen. Heat exposure causes metabolic and physiological disruptions in livestock. Ruminants and monogastric animals are very sensitive to heat stress due to their rate of metabolism, development, and higher production levels. Before slaughter, intense hot weather triggers muscle glycogen breakdown, producing pale, mushy, and exudative meat with less water-holding capacity. Animals exposed to prolonged high temperatures experience a decrease in their muscle glycogen reserves, producing dry, dark, and complex meat with elevated final pH and increased water-holding capacity. Furthermore, heat stress also causes oxidative stresses, especially secondary metabolites from lipid oxidation, severely affects the functionality of proteins, oxidation of proteins, decreasing shelf life, and food safety by promoting exfoliation and bacterial growth. Addressing the heat-related issues to retain the sustainability of the meat sector is an essential task that deserves an inclusive and comprehensive approach. Considering the intensity of the heat stress effects, this review has been designed primarily to examine the consequences of hot environment temperatures and related stresses on the quality and safety of meat and secondarily focus on cutting edge technology to reduce or alleviate the situational impact.

Observational Study Of Animal Slaughterhouses (RPH) Muaro Kumpeh Village Muaro Jambi

A slaughterhouse (RPH) is a building or building complex with certain designs and conditions used for slaughtering animals to produce safe, healthy, whole, and halal (ASUH) meat for consumption by the general public. This research aims to find out the process carried out by the RPH in carrying out its duties by Islamic law. In this research, the method used to analyze the Muaro Jambi Mandiri Enterprise RPH was to use literature review and observation methods to describe and explain the condition of the Mandiri Enterprise RPH in Muaro Kumpeh Village. The data used in this research uses primary data obtained directly through observation or interviews and secondary data. The data collection methods in this research are interviews and observations regarding the suitability of animal slaughtering, physical facilities, distribution of slaughtered products, and critical points. at this RPH. The study results show that this abattoir has carried out its business by Islamic law and has MUI halal certification. It was found that the critical point in this abattoir is in the place used for slaughtering animals, where the condition of the place is very at risk of unclean contamination.

Impact of dry aging on quality parameters and microbiological safety of beef

The market of dry aged meat is rapidly increasing. However, few papers report the impact of specific dry aging parameters on quality and microbiological safety of dry aged meat. In this study we assessed the impact of a 90 days dry aging process, performed in a commercial cabinet, on the quality parameters and microbiological safety of Holstein beef loins. Meat pH, colour indexes and fatty acids were stable during the process. Main volatile compounds’ concentration increased over time. Any oxidation of protein residues was detected and the main proteins undergoing proteolytic degradation early in the process were myoglobin, myofibrillar constituents and sarcoplasmic enzymes. The most significant histological changes started at 30 days and striation impairment was observed, not related to oxidative processes. The total bacteria count increased without signs of spoilage, Enterobacteriaceae were not enumerated and few reads of foodborne pathogens were detected by shotgun metagenomic. These results show that when the dry aging process is performed in a dedicated cabinet under strictly controlled process parameters, the microbiological safety of the meat is preserved. Our study provides the first insights of dry aged Holstein loins, whose valorisation would certainly enhance the economic, social and environmental sustainability of the Parmigiano Reggiano food system.

Consumers’ Preferences for Game Meat Safety: Results from a Choice Experiment

Investigating the determinant of consumer preference for game meat safety is crucial in promoting game meat consumption. In this study, we examined the impact on consumer preferences for a safety attribute, taking the individual risk attitude and the risk perception into account. We used data from a survey and a labeled discrete choice experiment involving 476 Italian consumers and analyzed it with a latent class model. The results show that all consumers gain utility from game meat with this safety claim. Furthermore, consistent groups of consumers who dislike game meat are likely to be risk-averse and perceive game meat as hazardous. Therefore, a marketing or public policy strategy aimed at promoting game meat consumption should focus on reinforcing consumers’ trust in more stringent safety standards. For instance, highlighting the safety measures and inspections involved in the production of game meat can help increase consumer confidence in its safety.

Improving meat quality and safety: innovative strategies

Ensuring meat products' quality and safety is paramount in today's food industry. This extended abstract delves into innovative strategies to enhance meat quality and safety throughout the production, processing, and distribution stages. The paper explores various cutting-edge approaches, technologies, and regulatory frameworks to mitigate risks and improve consumer confidence in meat products. The discussion begins with examining advancements in meat processing techniques, such as high-pressure processing (HPP), modified atmosphere packaging (MAP), and irradiation. These techniques are instrumental in reducing microbial contamination, extending shelf life, and preserving the nutritional integrity of meat products. Furthermore, the paper explores emerging technologies like nanotechnology and blockchain, which offer novel solutions for enhancing traceability, transparency, and accountability in the meat supply chain. Much of the paper discusses the role of quality control measures in ensuring meat safety and compliance with food safety regulations. From carcass inspection and microbiological testing to chemical residue analysis and packaging standards, rigorous quality control protocols are essential for identifying and mitigating potential hazards at every stage of meat production. Moreover, the paper highlights the importance of animal husbandry practices, feed management, and genetics in influencing meat quality attributes such as flavour, texture, and tenderness. Producers can enhance meat products' overall quality and palatability by implementing improved animal husbandry practices, optimizing feed formulations, and selectively breeding animals for desirable traits. In addition to technological advancements and quality control measures, the paper emphasizes the need for regulatory compliance and government oversight to uphold food safety standards. Ensuring adherence to regulations such as Hazard Analysis and Critical Control Points (HACCP) and implementing comprehensive food safety management systems are essential for safeguarding public health and consumer trust. In conclusion, this extended abstract provides a comprehensive overview of innovative strategies for improving meat quality and safety in the food industry. By embracing advancements in processing techniques, leveraging new technologies, implementing stringent quality control measures, and adhering to regulatory requirements, stakeholders can enhance the safety, integrity, and consumer perception of meat products in the marketplace.

Development of a harmonized and risk-based code system for post-mortem inspection of broilers

In most European countries, findings detected at post-mortem inspection (PMI) of broilers at slaughter are registered using national or regional code systems. The aim of this study was to map and compare existing national broiler PMI code systems in Europe and to suggest a new harmonized and risk-based code set intended to be interpreted in the same way in all countries. Information about the code systems, condemnation criteria, and the proportion of unfit broiler carcasses in 2022, as well as reasons justifying condemnation, were collected from nine European countries through an online survey. The reasons for declaring meat as unfit for human consumption were divided into food safety, meat quality, broiler health, or broiler welfare. The data were analyzed, and a risk-based code set consisting of 13 codes was developed. Ten of these new codes cover 80% of all condemnations listed in the data retrieved from the countries in the study. The remaining three codes are indicators of broiler welfare. The results were presented in the form of spider diagrams, indicating massive differences between the countries. Harmonization of the code list and the associated decision criteria will allow PMI to be conducted in the same way in different abattoirs and countries. This standardization of the PMI of broilers will enable detailed analysis of PMI results for further use in risk-based meat safety assurance systems and the implementation of computer-based vision systems at PMI in the future.

Recent Proteomics, Metabolomics and Lipidomics Approaches in Meat Safety, Processing and Quality Analysis

Recent Proteomics, Metabolomics and Lipidomics Approaches in Meat Safety, Processing and Quality Analysis

Outcomes of Microbiological Challenges in Poultry Transport: A Mini Review of the Reasons for Effective Bacterial Control

This review aims to highlight the main microbiological challenges faced in poultry transport and show the role of effective bacterial control during this process to ensure poultry health and meat safety and to reduce economic losses. Poultry infections are among the most frequent infections in production systems, manifesting themselves in hatcheries, farms, slaughterhouses, and during transport between these integration centers. Although the clinical symptoms of these infections can range from mild to severe, many of them can lead to irreversible conditions, resulting in death and compromising productive results. Bacteria are the main causative agents of these infections, although fungi, viruses, and protozoa may also be involved. During the transport of poultry from farms to slaughterhouses, poultry are very vulnerable to infectious conditions. Therefore, implementing effective antibacterial management, focused on professionals, transport crates, and transport vehicles, is essential to guarantee the survival and quality of poultry until the moment of slaughter.

Ozone treatment of meat and meat products: a review

Ozone treatment is a non-thermal method for disinfection; ozone is a powerful oxidizing agent that has been shown to be effective in reducing microbial load, extending the shelf life of meat products. This mini-review covers the analysis of the antimicrobial ozone activity in different meats (beef, poultry, pork, seafood, etc.), emphasizing the ozone application methods (liquid or gaseous phase), the applied concentrations and contact times and the effects of ozone treatment on meat quality, safety, and sensory properties. It has been demonstrated that ozone is effective against a broad range of microorganisms, including both Gram-positive and Gram-negative bacteria, spores, and vegetative cells. The efficacy of ozone depends on various factors, such as concentration, type of treatment, temperature, and presence of organic material. Ozone treatment, known for its rapid decomposition and lack of residue, provides an environmentally friendly alternative to traditional chemical sanitizers. Ozone treatments exhibit promising results in enhancing the safety and extending the shelf life of meat products. According to the findings, the application of ozone is an effective technology for prolonging the shelf life of different types of meats and meat products, requiring careful establishment of conditions on a case-by-case basis.

Characterization of two virulent Salmonella phages and transient application in egg, meat and lettuce safety

Salmonella, a prominent foodborne pathogen, has posed enduring challenges to the advancement of food safety and global public health. The escalating concern over antibiotic misuse, resulting in the excessive presence of drug residues in animal-derived food products, necessitates urgent exploration of alternative strategies for Salmonella control. Bacteriophages emerge as promising green biocontrol agents against pathogenic bacteria. This study delineates the identification of two novel virulent Salmonella phages, namely phage vB_SalS_ABTNLsp11241 (referred to as sp11241) and phage 8-19 (referred to as 8-19). Both phages exhibited efficient infectivity against Salmonella enterica serotype Enteritidis (SE). Furthermore, this study evaluated the effectiveness of two phages to control SE in three different foods (whole chicken eggs, raw chicken meat, and lettuce) at different MOIs (1, 100, and 10000) at 4°C. It’s worth noting that sp11241 and 8-19 achieved complete elimination of SE on eggs after 3 h and 6 h at MOI = 100, and after 2 h and 5 h at MOI = 10000, respectively. After 12 h of treatment with sp11241, a maximum reduction of 3.17 log10 CFU/mL in SE was achieved on raw chicken meat, and a maximum reduction of 3.00 log10 CFU/mL was achieved on lettuce. Phage 8-19 has the same effect on lettuce as sp11241, but is slightly less effective than sp11241 on chicken meat (a maximum 2.69 log10 CFU/mL reduction). In conclusion, sp11241 and 8-19 exhibit considerable potential for controlling Salmonella contamination in food at a low temperature and represent viable candidates as green antibacterial agents for food applications.

Safety of quail meat after drinking Chlorella suspension

Green algae Chlorella is positioned as a biologically active feed additive that includes proteins, polysaccharides, vitamins, minerals, glycoproteins and ß-glucans. Adding a small amount of them to the diet has a positive effect on the health and welfare of animals and poultry. However, their use in poultry farming requires an analysis of the quality and safety of the obtained products for the consumer. The purpose of the study is to assess the safety and quality of quail meat after drinking a suspension of Chlorella vulgaris microalgae. The object of study were quails of the Pharaoh breed, at the age of one day they were divided into two groups: experimental and control, 30 heads in each. The birds were kept in cages with free access to food and water. The quails of the research group were given a chlorella suspension (DSTU EK ISO 8692:2022 EN) in their drinking water. For drinking, the prepared chlorella suspension was diluted with drinking water to a concentration of 2*106 cells/ml grown in a glass fermenter. Weighing of quails was carried out weekly starting from day-old age. Drinking the suspension of Chlorella vulgaris increased the live weight of quail by 13.2 (p&lt;0.05) compared to the control. Pre-slaughter examination of quails of both groups revealed a satisfactory clinical condition of the bird. An examination of 20 quail carcasses showed that they can be attributed to the first grade. According to organoleptic indicators, quail meat in the veterinary and sanitary sense belongs to benign quality. The conducted microbiological studies of quail meat show that there is no effect of the microalgae Chlorella sorokiniana in the applied doses on its bacterial contamination. The chemical parameters of the meat (pH, amino ammonia nitrogen, volatile fatty acids) during storage in the refrigerator (5 days, t= 4–5 °C) tended to increase and were within the normal range for a fresh product. During microscopy, m ulcer tissue and its disintegration were not detected in quails of both groups. The biological value of quail meat of both groups was identical, and there was no toxicity. The tasting evaluation of the broth and meat showed that drinking the microalgae Chlorella sorokiniana does not affect the studied taste indicators. Therefore, the meat of quails that received the microalgae Chlorella sorokiniana feed additive with water is of good quality according to the veterinary and sanitary examination, which allows it to be used for human consumption without restrictions. Key words: poultry, microalgae, organoleptic evaluation, microbial contamination, biological value, tasting evaluation.&gt; &lt;0.05) compared to the control. Pre-slaughter examination of quails of both groups revealed a satisfactory clinical condition of the bird. An examination of 20 quail carcasses showed that they can be attributed to the first grade. According to organoleptic indicators, quail meat in the veterinary and sanitary sense belongs to benign quality. The conducted microbiological studies of quail meat show that there is no effect of the microalgae Chlorella sorokiniana in the applied doses on its bacterial contamination. The chemical parameters of the meat (pH, amino ammonia nitrogen, volatile fatty acids) during storage in the refrigerator (5 days, t= 4–5 °C) tended to increase and were within the normal range for a fresh product. During microscopy, mulcer tissue and its disintegration were not detected in quails of both groups. The biological value of quail meat of both groups was identical, and there was no toxicity. The tasting evaluation of the broth and meat showed that drinking the microalgae Chlorella sorokiniana does not affect the studied taste indicators. Therefore, the meat of quails that received the microalgae Chlorella sorokiniana feed additive with water is of good quality according to the veterinary and sanitary examination, which allows it to be used for human consumption without restrictions. Key words: poultry, microalgae, organoleptic evaluation, microbial contamination, biological value, tasting evaluation.

Quality and safety of pork meat after cooling and treatment with lactic starters

Cooling the pork half-carcasses in a refrigerating chamber with showering had no significant impact on their surface temperature. Still, it reduced the core temperature of the meat in 1 hour after cooling compared with air-cooling. pH-value of all pork half-carcasses that were subjected to cooling with the showering method, as well as the final processing of the pork with suspensions of Lactobacillus sakei and Leuconostoc carnosum in 1 hour and on the 4th day of storage in a chilled condition was within the limits typical for fresh and high-quality meat. The greatest weight loss of the pork half-carcasses occurred during the first 24 hours when they were being cooled. The weight loss of the pork half-carcasses in a chilled condition during 1 day when they were being cooled in a refrigerating chamber without the use of showering was 2.27%, when they were being cooled with the use of showering – 1.65%, when they were being cooled with the use of showering and final processing with SafePro® В-SF-43 (Leuconostoc carnosum) – 1.61% and SafePro® В-2 (Lactobacillus sakei) – 1.25% in comparison with the output of a hot carcass. Microorganism cultures of strains SafePro® B-SF-43 and SafePro® B-2, when they are applied at a dose of 106/cm2, had contributed to a colonization of the meat with the lactic-acid microorganisms and a significant decrease in the number of QMAFAnM in the neck and spine areas in 1 hour after cooling. S. aureus, Salmonella spp., and L. monocytogenes were not detected in the meat of the pork half-carcasses in all processing options during 4 days of storage in a chilled condition.

The Effect of the PhoP/PhoQ System on the Regulation of Multi-Stress Adaptation Induced by Acid Stress in Salmonella Typhimurium.

Acidic stress in beef cattle slaughtering abattoirs can induce the acid adaptation response of in-plant contaminated Salmonella. This may further lead to multiple resistance responses threatening public health. Therefore, the acid, heat, osmotic and antibiotic resistances of Salmonella typhimurium (ATCC14028) were evaluated after a 90 min adaption in a pH = 5.4 "mild acid" Luria-Bertani medium. Differences in such resistances were also determined between the ∆phoP mutant and wild-type Salmonella strains to confirm the contribution of the PhoP/PhoQ system. The transcriptomic differences between the acid-adapted and ∆phoP strain were compared to explore the role of the PhoP/Q two-component system in regulating multi-stress resistance. Acid adaptation was found to increase the viability of Salmonella to lethal acid, heat and hyperosmotic treatments. In particular, acid adaptation significantly increased the resistance of Salmonella typhimurium to Polymyxin B, and such resistance can last for 21 days when the adapted strain was stored in meat extract medium at 4 °C. Transcriptomics analysis revealed 178 up-regulated and 274 down-regulated genes in the ∆phoP strain. The Salmonella infection, cationic antimicrobial peptide (CAMP) resistance, quorum sensing and two-component system pathways were down-regulated, while the bacterial tricarboxylic acid cycle pathways were up-regulated. Transcriptomics and RT-qPCR analyses revealed that the deletion of the phoP gene resulted in the down-regulation of the expression of genes related to lipid A modification and efflux pumps. These changes in the gene expression result in the change in net negative charge and the mobility of the cell membrane, resulting in enhanced CAMP resistance. The confirmation of multiple stress resistance under acid adaptation and the transcriptomic study in the current study may provide valuable information for the control of multiple stress resistance and meat safety.