Minced Pork Meat Research Articles

Antilisterial activity of olive-derived polyphenols: an experimental study on meat preparations

Pork meat and processed pork products have been linked to multiple listeriosis outbreaks worldwide during the past years. Specifically, it has been highlighted that minced pork meat is easily perishable and may increase the growth of Listeria monocytogenes, which could be harmful to the general public's health. This study aimed to investigate the potential application of olive oil mill wastewater polyphenolic and red beet extracts as natural antimicrobial agents for L. monocytogenes growth control in burgers. The minced pork meat was mixed with the extracts and experimentally inoculated with L. monocytogenes, then molded into vacuum-packaged and cold-stored (4±1°C) burgers kept under alternating exposure to fluorescent light. The L. monocytogenes enumeration was performed on burgers at 0, 2, 5, and 10 days of shelf life. In uninoculated burgers, physicochemical (pH, water activity, color) and sensory determination (descriptive sensory analysis) were also conducted. At the end of storage, the samples treated with olive-derived extract showed the lowest value of L. monocytogenes (approximately 1.3 Log CFU/g). The physicochemical and sensory traits of burgers have benefited from the addition of both olive-derived and red beet extracts. Results suggest that olive mill wastewater polyphenolic extracts could be added to minced pork meat products to act as a natural antimicrobial agent.

Using Essential Oils to Reduce Yersinia enterocolitica in Minced Meat and in Biofilms.

Yersiniosis, one of the leading foodborne infections in the European Union, is caused by Yersinia enterocolitica. In this study, the antibacterial and antibiofilm effects of cinnamon (Cinnamomum zeylanicum Nees), clove (Syzygium aromaticum L.), oregano (Origanum vulgare L.), rosemary (Rosmarinus officinalis L.), thyme (Thymus vulgaris L.), and winter savory (Satureja montana L.) essential oils were investigated against Y. enterocolitica strains belonging to the bioserotype 4/O:3. Cinnamon essential oil showed the highest antibacterial activity, with an MIC value 0.09 µL/mL, followed by oregano and thyme essential oils, with MIC values from 0.09 to 0.18 µL/mL, and from 0.18 to 0.23 µL/mL, respectively. Thyme essential oil at 0.23 µL/g (MIC) and at 0.46 µL/g (2MIC) significantly (p < 0.05) reduced the number of Y. enterocolitica by 0.38 log CFU/g and 0.64 log CFU/g, respectively, in minced pork meat during storage at 4 °C for 4 days. The Y. enterocolitica strains formed biofilms at 15 °C and 37 °C in tryptic soy broth and Luria-Bertani broth, while no biofilms were obtained at 5 °C, and in meat broth nutrient media. Applying the minimum bactericidal concentrations of cinnamon, clove, oregano, rosemary, thyme, and winter savory essential oils on preformed biofilms led to significant reductions being observed in the range from 45.34% to 78.89%. A scanning electron microscopy assay showed the devastating impact of oregano and thyme essential oils on the morphology of Y. enterocolitica bacterial cells. In conclusion, the results of this study show that essential oils possess high anti-Yersinia and antibiofilm effects.

Wild fennel seeds from Valle Agricola (Southern Italy): Biochemical and antioxidant traits in minced pork meat

Here, we report the nutritional (crude proteins, total and free amino acids, fatty acids, minerals) and biochemical (protease inhibitors and antioxidant enzymes) characterization of wild fennel seeds from ‘Valle Agricola’ (Caserta, Italy), typical local products used as a food flavouring and preservative. The comparative analysis with commercial fennel seeds revealed the higher antioxidant activity of wild fennel seeds and the considerable ability of the latter in food preservation. In light of this, both wild and commercial fennel seeds were added to minced pork meat to evaluate the effect of flavouring treatment at 0, 1, 3 and 7 days. The analysis revealed that free amino acids, fatty acids and glycosidically bound volatile compounds responsible for meat taste and aroma were mainly released following wild fennel seeds addition.Overall, these data encourage the local consumption of traditional spices, usually added to traditional dry-cured meat and open new opportunities for the niche market.

Carvacrol Microemulsion vs. Nanoemulsion as Novel Pork Minced Meat Active Coatings.

Carvacrol is well documented for its antibacterial and antioxidant effects. However, its high volatility has directed researchers toward nanoencapsulation technology according to bioeconomy and sustainability trends. This study examined and compared free carvacrol (FC), carvacrol microemulsion (MC), carvacrol microemulsion busted with chitosan (MMC), and carvacrol nanoemulsions (NC) as active coatings on extending minced pork meat shelf life at 4 ± 1 °C for 9 days, focusing on microbiological, physiochemical, and sensory characteristics. The research involved pre-characterizing droplet sizes, evaluating antioxidants, and determining antibacterial efficacy. The results demonstrated that NC with a 21 nm droplet size exhibited the highest antioxidant and antibacterial activity. All coatings succeeded in extending the preservation of fresh minced pork meat in comparison to the free carvacrol sample (FC). The NC coating showed the highest extension of minced pork meat preservation and maintained meat freshness for 9 days, with a lower TBARs of 0.736 mg MDA/Kg, and effectively reduced mesophilic, lactic acid, and psychotrophic bacterial counts more significantly by 1.2, 2, and 1.3 log, respectively, as compared to FC. Sensory assessments confirmed the acceptability of NC and MCC coatings. Overall, the carvacrol-based nanoemulsion can be considered a novel antioxidant and antimicrobial active coating due to its demonstrated higher efficacy in all the examined tests performed.

Beetroot juices as colorant in plant-based minced meat analogues: Color, betalain composition and antioxidant activity as affected by juice type

The aim of this work was to study the suitability of the application of beetroot juices (obtained from fresh beetroot, cooked beetroot, beetroot powder and commercial beetroot juice) as colorants in the development of meat analogues, as well as their antioxidant properties. Fresh beetroot juice showed the highest betalain content (119.53 mg betanin/100 ml and 48.27 mg vulgasanthin I/100 ml) and commercial juice the lowest (49.40 mg betanin/100 ml and 7.21 mg vulgasanthin I/100 ml). Juices from fresh and cooked beetroot showed ABTS, FRAP and FIC values higher than values obtained for commercial juice (ascorbic acid added). Textured soy protein with cooked beetroot juice or with commercial juice showed the same appearance that of minced beef and pork meat, respectively, which is in accordance with their hue values and reflectance spectra. The attractive red color of betalains and their stability at the pH value of meat analogues make beetroot juices ideal for their application as colorants in meat analogues.

Effects of Selected Essential Oils on Listeria monocytogenes in Biofilms and in a Model Food System.

The composition of 18 essential oils was determined using gas chromatography-mass spectrometry, and their antilisterial activity was evaluated by the disk diffusion method, followed by the determination of the minimum inhibitory and minimum bactericidal concentrations. The most active essential oils were oregano, thyme, cinnamon, winter savory, and clove, with MIC values ranging from 0.09 to 1.78 µL/mL. We investigated the biofilm-forming potential of Listeria monocytogenes on polystyrene at 5 °C, 15 °C, and 37 °C in three different media. The formation of biofilm was found to be dependent on the temperature and the availability of nutrients. After treatment with selected essential oils, the reduction in biofilm biomass was in the range of 32.61% and 78.62%. Micromorphological changes in the L. monocytogenes treated by oregano and thyme essential oils were observed in the form of impaired cell integrity and cell lyses by using scanning electron microscope. Oregano and thyme essential oils (MIC and 2MIC) significantly (p < 0.05) reduced the population of L. monocytogenes in minced pork meat during storage at 4 °C. In conclusion, the obtained results indicated the good activity of some selected essential oils on L. monocytogenes, with bacteriostatic, bactericidal, and antibiofilm effects at very low concentrations.

Lid Films of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/Microfibrillated Cellulose Composites for Fatty Food Preservation.

The present work evaluates the food packaging performance of previously developed films of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) reinforced with atomized microfibrillated cellulose (MFC) compatibilized by a reactive melt-mixing process. To this end, the novel green composite films were originally applied herein as lids in aluminum trays to preserve two dissimilar types of fatty foods, namely minced pork meat and sunflower oil. Results indicated that the PHBV/MFC films effectively preserved the physicochemical and microbiological quality of pork meat for one week of storage at 5 °C. In particular, the compatibilized green composite lid film yielded the lowest weight loss and highest oxidative stability, showing values of 0.935% and 0.78 malonaldehyde (MDA)/kg. Moreover, none of the packaged meat samples exceeded the acceptable Total Aerobial Count (TAC) level of 5 logs colony-forming units (CFU)/g due to the improved barrier properties of the lids. Furthermore, the green composite films successfully prevented sunflower oil oxidation in accelerated oxidative storage conditions for 21 days. Similarly, the compatibilized PHBV/MFC lid film led to the lowest peroxide value (PV) and conjugated diene and triene contents, with respective values of 19.5 meq O2/kg and 2.50 and 1.44 g/100 mL. Finally, the migration of the newly developed PHBV-based films was assessed using two food simulants, proving to be safe since their overall migration levels were in the 1-3 mg/dm2 range and, thus, below the maximum level established by legislation.

Wireless Powering and Telemetry of Deep-Body Ingestible Bioelectronic Capsule

In this article, a complete and efficient wireless power transfer (WPT) system, consisting of a full-duplex antenna, a half-wave rectifier, and a WPT transmitter (Tx), is designed and validated for deep-body ingestible biomedical capsules. A two-port full-duplex antenna is adopted to perform seamless telemetry and to act as a receiver for WPT Tx without using a multiplexer circuit. The full-duplex implantable antenna operates at 915 MHz (Port 1) and 1300 MHz (Port 2) and occupies compact dimensions of 8 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 8 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 0.13 mm 3. It maintains high isolation of >30 dB and peak realized gains of −19.3 dBi at 915 MHz and −17.7 dBi at 1300 MHz. The miniaturization of this antenna is achieved using semicircular slots on the patch and circular slots on the ground plane while mutual coupling between the ports is reduced by a series of metallic vias. Moreover, a low-profile and efficient rectifier is designed at 1300 MHz and integrated with port 2 of the antenna. The suggested rectifier achieves a radio frequency (RF) to direct current (dc) conversion efficiency of 80.4% at an input power of 1 dBm. Furthermore, a patterned patch antenna is designed that acts as a WPT Tx for the biomedical capsule. After examining the individual performance of the antenna, rectifier, and WPT Tx, the overall WPT system is then validated by placing the capsule (rectifier integrated antenna) inside minced pork meat and powered by the WPT Tx. This WPT system is suitable for modern capsule devices due to its features, such as compact size, high gains, high RF-dc conversion efficiency, simultaneous wireless powering and telemetry, and high-power transfer efficiency (PTE).

Effects of cocaine and heroin, and their combination, on the development rate of Calliphora vomitoria (Diptera: Calliphoridae)

Insects present on or near decomposing bodies are collected by forensic entomologists and used to estimate the post-mortem interval. Drugs metabolized by a person before death may affect the rate of development of insects feeding on the corpse. This study aimed to determine the effects of cocaine and heroin main metabolites on the development rate of the Calliphora vomitoria (Diptera: Calliphoridae) and their implications on minimum post-mortem interval determination. Groups of 250 eggs each were placed into four separate pots of 150 g of minced pork meat being either un-spiked, or spiked with benzoylecgonine, morphine, or a combination of both. Larval length (mm) and weight (mg) measurements were taken twice daily and the rate of development of the insects’ life cycle was monitored until eclosion. Results show that cocaine-fed larvae developed less in length and weight than the control group. Heroin-fed larvae showed a more fluctuating pattern, being smaller and lighter than the control group for most of their larval cycle, but overtaking them in both parameters towards pupation. Combination-fed larvae seemed to favour the effects of cocaine. The three conditions also had a significant impact on the length of the insects’ life cycle. Cocaine and drug combination treatments increased the length of the second and third instar stages, but led to the shortening of pupation and accelerated eclosion. Conversely, heroin treatment led to lengthier pupation. Interestingly, the effects of the drug combination seemed to mirror more precisely those of cocaine.These findings indicate that both cocaine and heroin, singularly and in combination, have sizable effects on blowflies’ development rates, potentially biasing post-mortem interval estimations.

Compact triple-band implantable antenna for multitasking medical devices

Abstract This paper presents a compact implantable antenna’s design, fabrication, and measurement for biotelemetry applications. The proposed design with the size of 255 mm3 provides a triple-band operation that covers all the Medical Implant Communication Service (MICS: 402 MHz), Medical Device Radiocommunications Service (MedRadio: 405 MHz), and Industrial, Scientific, and Medical (ISM: 433, 915 and 2450 MHz) bands simultaneously. The compact structure with triple- band performance is essentially achieved by using a spiral-like radiator loaded with meandered and internal gear-shaped elements excited by a vertical coaxial probe feed. Also, the slots-loaded partial ground plane is utilized to improve impedance matching at the desired frequency bands. The design and analysis of the antenna were carried out using the Ansoft HFSS software in a homogenous skin model and the CST Microwave Studio in a realistic human model. The proposed antenna was fabricated to validate the simulated results, and characteristics of its return loss and radiation patterns were measured in minced pork meat. Moreover, realized gains and specific absorption rate (SAR) values of the antenna were numerically computed using the simulators. Based on the simulated and measured results, the proposed antenna performance was found to be comparable to the limited number of multiband implantable antenna designs reported in the recent literature.

A Compact Implantable MIMO Antenna for High-Data-Rate Biotelemetry Applications

This article presents a low-profile multiple-input–multiple-output (MIMO) implantable antenna system, including a capsule endoscopy and a scalp implantation at medical implant communication service (MICS) band (402–405 MHz), and industrial, scientific, and medical (ISM) band (433.1–438.8 MHz). It consists of two elements with an edge-to-edge gap of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.0018\lambda _{g}$ </tex-math></inline-formula> and overall dimensions of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pi \times (5.65)^{2} \times 0.13$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> and is placed on a 0.13 mm-thick RO3010 ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\epsilon _{r} = 10.2$ </tex-math></inline-formula> and tan <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\delta = 0.0022$ </tex-math></inline-formula> ) substrate. The antenna is integrated with batteries, sensors, and electronic components in two different types of implantable devices (capsule and flat-type devices). The simulation result shows that the antenna has a fractional bandwidth (FBW) of 33.9%, a maximum realized gain of −30 dBi, and isolation of more than 26 dB. The fabricated prototype is measured in a saline solution and minced pork meat. The measured results are found in good accordance with simulations. The antenna parameters are calculated and showed a significant independence between the radiators. A link budget is estimated to be 78 Mb/s for a distance of 20 m. Thus, the proposed antenna is considered as a promising solution for high-data-rate medical applications such as capsule endoscopy, live surgeries, and other biomedical applications where the high data rate is required.

Low-profile dual-band implantable antenna for compact implantable biomedical devices

In this paper, A miniaturized dual-band implantable antenna using meandered line resonator is proposed for bio-telemetry applications. The proposed antenna has dual-band (0.91 GHz and 2.45 GHz) operation, covering the important Industrial, Scientific and Medical (ISM) bands. Miniaturization is achieved using meandered resonator and a square slot etched in the ground plane. The performance of the proposed antenna inside a quasi-implantable biomedical device (IBD) is analysed in a homogeneous skin model, human intestine and human head. The measurements are performed by implanting the quasi-IBD inside a saline solution and minced pork meat. The quasi-IBD consists of the proposed antenna, batteries and printed circuit board (PCB) with electronic components on it. The proposed antenna has compact dimensions of 5.6 ×5.8× 0.25 mm3. The measured peak gains in the minced pork meat are −22.9 dBi and −22.1 dBi at 0.91 GHz and 2.45 GHz, respectively. The low specific absorption rate (SAR) of the proposed antenna allows maximum input power of 3.32 mW at 0.91 GHz and 4.37 mW at 2.45 GHz. To the best of the authors’ knowledge, this is the most compact dual-band implantable antenna reported in the literature for 0.91 GHz and 2.45 GHz ISM bands.

Predictive modelling of TBARS changes in the intramuscular lipid fraction of raw ground pork enriched with plant extracts

The aim of the study was to develop and compare the predictive models of lipid oxidation in minced raw pork meat enriched with selected plant extracts (allspice, basil, bay leaf, black seed, cardamom, caraway, cloves, garlic, nutmeg, onion, oregano, rosemary and thyme) by investigation TBARS values changes during storage at different temperatures. Meat samples with extract addition were stored under various temperatures (4, 8, 12, 16, and 20°C). TBARS values changes in samples stored at 12°C were used as external validation dataset. Lipid oxidation was evaluated by the TBARS content. Lipid oxidation increased with storage time and temperature. The dependence of lipid oxidation on temperature was adequately modelled by the Arrhenius and log-logistic equation with high R2 coefficients (0.98–0.99). Kinetic models and artificial neural networks (ANNs) were used to build the predictive models. The obtained result demonstrates that both kinetic Arrhenius (R2 = 0.83) and log-logistic (R2 = 0.84) models as well as ANN (R2 = 0.99) model can predict TBARS changes in raw ground pork meat during storage.

Improved prediction of minced pork meat chemical properties with near-infrared spectroscopy by a fusion of scatter-correction techniques

The modelling near-infrared (NIR) spectroscopy data requires removal of scattering effects from the data before applying advanced chemometrics methods. Often different scatter-correction techniques are explored, and the scatter-correction technique with the best performance is selected. However, the information highlighted by different scatter-correction techniques may be complementary and their fusion may result in better models for predicting characteristics, such as meat quality. To test this, sequential and parallel preprocessing fusion approaches will be used in this work to fuse information from different scatter-correction techniques to try to improve the predictive performance of NIR models. Three different chemical properties, i.e., moisture, fat and protein content, were predicted. For comparison, partial least-squares regression (PLSR) was performed on standard normal variate (SNV) corrected data, as this is a widely used scatter-correction technique. Compared to this commonly used procedure, the scattering fusion approaches reduced the error and bias by up to 52% and 84%, respectively. The results suggest that fusion of scatter-correction techniques is essential to achieve optimal NIR prediction models for predicting meat characteristics such as moisture, fat and protein content.

Fennel essential oil loaded porous starch-based microencapsulation as an efficient delivery system for the quality improvement of ground pork

Porous starch (PS) was used as the core material carrier to adsorb fennel essential oil (FEO). Using sodium alginate (SA)-chitosan (CS) as the wall material and glutaraldehyde as the curing cross-linking agent, CS/SA/PS-FEO microcapsules were successfully prepared by polyelectrolyte complex coagulation method. The formation process, structural properties and release behavior of CS/SA/PS-FEO microcapsules were analyzed. The results showed that the essential oil was encapsulated in the form of micro-capsules according to infrared spectroscopy and X-ray diffraction analysis. In open and closed systems, the 16-day cumulative release rate of FEO obtained was 70.62% and 43.87%, respectively indicating that the prepared CS/SA/PS-FEO microcapsules had a good sustained-release ability. The fennel essential oil micro-capsules exhibited good antibacterial and antioxidant activities, delayed the oxidation of fat and protein, reduced the total viable counts, total volatile-base nitrogen and methemoglobin. The textural property and status of water (analyzed by NMR) suggested that the quality of the meat can be maintained for an extended period by incorporating the CS/SA/PS-FEO microcapsules in the minced pork meat.

Comparison of two antioxidant packaging based on rosemary oleoresin and green tea extract coated on polyethylene terephthalate for extending the shelf life of minced pork meat

Two antioxidant active packaging systems containing rosemary oleoresin and green tea extract for meat preservation were compared. Minced pork was packaged in active films and its quality was evaluated by sensory analysis, color, thiobarbituric acid reactive substances (TBARS) and total volatile basic nitrogen content (TVB-N). The active films coated with green tea extract showed high antioxidant capacity. The TBARS value of meat packaged with films containing 6 % green tea at day 14 was 0.62 mg of malonaldehyde/kg of meat. This value was equal to day 0 value of TBARS and 37 % lower than the TBARS value of pork in blank group at day 14. The TVB-N values obtained for 6 % green tea and 8 % rosemary at day 14 were 40 and 39 mg N/100 g meat, approximately 25 % lower than the blank. These results indicate the potential application of active films with green tea extract in meat preservation.

Screening of volatile decay markers of minced pork by headspace-solid phase microextraction–gas chromatography–mass spectrometry and chemometrics

Headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME–GC–MS) was used to analyze the volatile compounds of minced pork meat during storage. The origin of aromatic hydrocarbons in pork was verified by migration test. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were applied to characterize the profile of volatile compounds in pork meat and identify the potential volatile markers associated with the spoilage of pork. A total of 41 compounds were identified. Migration test showed that the aromatic hydrocarbons in raw pork are from packaging. Three compounds: ethanol, 2,3-butanediol and 2-ethyl-1-hexanol were selected based on the loading plot and their variables importance in the projection (VIP) values, since they contribute mainly to the discrimination of pork with different storage times. These compounds can be used as additional indicators for quality control of pork.

Occurrence, Antimicrobial Resistance and Molecular Diversity of Enterococcus faecium in Processed Pork Meat Products in Korea.

Because Enterococcus faecium is an important nosocomial pathogen and sentinel organism for tracking antimicrobial resistance, information on the contamination and antimicrobial resistance patterns of E. faecium in food are essential to public health and food safety. We analyzed the occurrence of E. faecium in retail pork meat products (n = 124), and antimicrobial resistance of 30 E. faecium isolates were examined against 14 antimicrobials using the broth dilution test and disc diffusion test. Rep-PCR-based molecular diversity was also analyzed using Deviersilab. The highest contamination of enterococci was observed for minced pork meat but most of the E. faecium was isolated from meatball-type frozen pork meat products (FP). Incidences of antimicrobial-resistant E. faecium against erythromycin, clindamycin and nitrofurantoin were 80%, 50% and 20%, respectively. No vancomycin-resistant enterococci were analyzed. Rep-PCR showed distinctive clusters with a similarity ≥ 98%, consisting of 18 E. faecium isolates from FP manufactured in seven companies. The analyzed data on the contamination and antimicrobial resistance patterns combined with molecular typing can be useful to derive risk management of antimicrobial-resistant enterococci in food.

A study on pork sausage incorporated with olive oil, dried apple pulp powder and pomegranate seed powder

The purpose of this study is to evaluate the effect of olive oil, dried apple pulp powder and pomegranate seed power in traditional pork sausage in refrigeration storage. Pork sausage were prepared, namely, T1 (traditional pork sausage batter was manually mixed) and T2 (low fat pork sausage batter was manually mixed). Pork sausage is traditionally produced by minced pork meat and pork fat. Low fat pork sausage was prepared by using minced pork meat, olive oil, dried apple pulp powder and pomegranate seed powder. The products were compared on the basis of physicochemical and sensory qualities at different interval under refrigerated (4±1°C) conditions. Among the treatments, pH was recorded lower for T2 compared to T1 treatment with the advancement of the storage periods. The mean tyrosine value and thio-barbituric acid number of all the treatment showed increasing trend with the advancement of the storage period. The sensory evaluation revealed highest scores for colour and appearance, flavour, texture, and overall acceptability for T2 than T1 but juiciness score was more in T1. The manuscript has stated that adding of dried apple pulp powder and pomegranate seed powder improved all the attributes (physicochemical and sensory) and also ensured a longer shelf-life of the product.

Plasmid-Encoded blaNDM-5 Gene That Confers High-Level Carbapenem Resistance in Salmonella Typhimurium of Pork Origin.

PurposeCarbapenem resistance is rarely reported in Salmonella Typhimurium, especially from a food origin. Here, we report a plasmid-mediated mobile carbapenem-resistant blaNDM-5 gene in Salmonella Typhimurium isolated from pork in Shanghai, China in 2016.Patients and MethodsIn July 2016, the S. Typhimurium SH160 strain was recovered from minced pork meat purchased from a supermarket in Yangpu District, Shanghai, China. Antimicrobial susceptibility testing, multi-locus sequence typing, conjugation, S1-PFGE, southern hybridization, whole-genome sequencing and data analysis were performed.ResultsThis isolate was found to be a ST34 strain and resistant to carbapenems, cephalosporins, and most other commonly used antibiotics. The blaNDM-5 gene was harbored by a 46161-bp IncX3 plasmid which was found to be transferable. The IncX3 plasmid contains a composite cassette, consisting of ISSwil-IS3000-ΔISAba125-IS5-blaNDM-5-bleMBL-trpF-dsbC-IS26-ctuA1-ΔumuD. In addition, this strain was found to harbor an additional 161706-bp IncHI2 plasmid which carries nine resistant genes, such as aadA1, aadA3, aph(3ʹ)-la, sul1, sul2, sul3, floR, cmlA and dfrA12.ConclusionWe reported the S. Typhimurium with transferable IncX3 plasmid harboring blaNDM-5 gene from minced pork. We characterized the complete genetic features of the plasmid, which demonstrated the potential for spreading in different bacterial pathogens. Therefore, extensive surveillance and monitoring for carbapenem-resistant bacterium in the food chain and public health are urgently required.