Search Results (165)

Listeria monocytogenes is often found in pork intestines and can contaminate pork production, posing a risk to consumers. This study aimed to characterize 16 L. monocytogenes isolates from fresh and packaged pork loin, identify their serotypes, and assess antibiotic resistance. To evaluate chitosan susceptibility as a potential strategy to control L. monocytogenes in the pork industry and to determine its effectiveness in a eukaryotic model to demonstrate pathogenicity. Among the 16 isolates examined, 2 were identified as 1/2a, 12 as 1/2b, 2 as 4b, and 2 could not be assigned a serotype. Variations were observed in their pathogenicity factors. Some isolates were lacking in some virulence factors. In the antibiotic assays, all isolates demonstrated resistance to at least three antibiotics, and one of them exhibited resistance to as many as ten antimicrobial agents. To propose an alternative in the food industry as a decontamination agent, a low-molecular-weight chitosan was evaluated. It was shown that chitosan inhibits the growth of L. monocytogenes in a concentration of 0.25% in 45 min, resulting in a viable alternative against this pathogen, but in this work, one isolate exhibited resistance to chitosan (isolate Lm 1.2). Regarding infection in eukaryotic models, all isolates had the capacity to infect chicken embryos, except for isolate 1.2, which exhibited attenuated pathogenicity. These findings highlight the potential public health risk L. monocytogenes poses in pork and the need for continued research to develop effective control strategies. Full article

High-risk clones represent a major concern, as they are very efficient vehicles for mobile genetic elements carrying antimicrobial resistance genes and therefore promote their spread, especially if they confer resistance to cefotaxime, ciprofloxacin, and fosfomycin, included within the highest-priority, critically important antimicrobial agents (HPCIA). Between February 2022 and April 2024, 138 pork samples were obtained from 46 butcher shops in La Plata, Buenos Aires, Argentina. A total of 102 HPCIA-resistant E. coli were isolated. Eighty-five HPCIA-resistant E. coli were selected for whole-genome sequencing. Of these, 27 belonged to 9 clones described as high risk: ST101 (n = 5), ST10 (n = 4), ST48 (n = 4), ST744 (n = 4), ST23 (n = 3), ST58 (n = 2), ST88 (n = 2), ST117 (n = 2), and ST410 (n = 1). Twelve of them were third-generation cephalosporin-resistant. Resistance was mediated by bla_CTX-M-55 (n = 7), bla_CTX-M-14 (n = 4), bla_CTX-M-8 (n = 1), and bla_CMY-2 (n = 1). This study highlights the importance of food products and the food production chain as reservoirs of high-risk clones and resistance genes of epidemiological relevance to public health. Full article

Due to the prevalence of plastic-packaged foods, as well as the need for real-time food monitoring by consumers, reducing plastic pollution is essential for a healthier environment and nutrition. For these reasons, in this work, biodegradable pH-responsive chitosan films enriched with wine lees-derived anthocyanins were produced, and their pH sensitivity was thoroughly evaluated. Optimization of ultrasound-assisted extraction using ethanol/water mixtures as conventional solvents was conducted and the optimal conditions (regarding total anthocyanin content, total phenolic content, and antioxidant activity) were used to perform a screening of extraction with 16 different Natural Deep Eutectic Solvents. Among them, choline chloride: butylene glycol (1:4), at a concentration of 50% v/v in water, demonstrated the highest anthocyanin recovery and was selected for the preparation of the films. The resulting films exhibited an excellent colorimetric response to pH changes, with a color difference (ΔE) exceeding 6.8 at all tested pH values, improved mechanical properties, nearly zero UV permeability, and their antioxidant activity increased by up to 6.1-fold compared to pure chitosan film. Finally, the film was applied in detecting the freshness of pork meat, exhibiting a ΔE of 15.3. The results demonstrate that the developed film is a promising alternative for intelligent, bioactive, and biodegradable food packaging for food applications. Full article

This study examines the effects of an emulsion gel (EG) and a fat bulking agent (BA), both formulated with pork lard (PL) and an alginate-based gelling system, as animal fat replacers in the reformulation of reduced-fat fresh pork sausages. Both fat analogs were characterized in terms of texture, color, and in vitro gastrointestinal digestion (GID) before being used in the reformulation of four fresh pork sausages, without and with added silicon (Si) from diatomaceous earth powder: S/EG, S/EG-Si, S/BA, and S/BA-Si. Reduced-fat sausages elaborated exclusively with pork backfat (PB), without and with Si, were used as controls (S/C and S/C-Si). Both EG and BA showed adequate physicochemical characteristics and slowed in vitro GID compared to PL and PB. Replacing 75% PB with EG or BA did not negatively impact the technological, nutritional, or sensory properties of the reformulated pork sausages, which were kept for 14 days under refrigeration. Additionally, sausages containing EG or BA as fat substitutes presented lower lipid digestibility after in vitro digestion compared to the control samples. The addition of Si further limited fat digestion, as reflected by the lower release of free fatty acids after in vitro GID compared to products without added Si. This effect was more pronounced in EG-based formulations. Therefore, the use of EG as a PB replacer, together with the addition of Si, could become a promising strategy for developing healthier meat products. This finding may have important implications for the development of functional meat products aimed at reducing fat content and lipid absorption, thereby laying the foundation for precision nutrition strategies focused on improving individual health outcomes. Full article

The visual colorimetric sensing of total volatile basic nitrogen (TVB-N) allows for convenient dynamic monitoring of animal-derived food freshness to ensure food safety. The agarose hydrogel loaded with the natural dye juglone (Jug@AG) prepared in this study exhibits visible multicolor changes from yellow to grayish-yellow and then to brownish with increasing TVB-N gas concentration, achieving sensitive detection of TVB-N gas at concentrations as low as 0.05 mg/dm³ within 8 min. The minimum observable amounts of TVB-N in spiked pork and fish samples are 8.43 mg/100 g and 8.27 mg/100 g, respectively, indicating that the Jug@AG hydrogel possesses sensitive colorimetric sensing capability in practical applications. The Jug@AG hydrogel also shows significant changes in color difference value (∆C) under both room temperature (25 °C) and cold storage (4 °C) conditions, with the changing trends of ∆C showing consistency with the measured TVB-N and total viable counts (TVC) during the transition of pork and fish samples from freshness to early spoilage and then to spoilage. The results indicate that the Jug@AG hydrogel can be used as a colorimetric sensor to achieve real-time dynamic freshness monitoring of animal-derived food. Full article

Deep learning approaches for pork freshness grading typically require large datasets, which limits their practical application due to the high costs associated with data collection. To address this challenge, we propose BBSNet, a lightweight few-shot learning model designed for accurate freshness classification with a limited number of images. BBSNet incorporates a batch channel normalization (BCN) layer to enhance feature distinguishability and employs BiFormer for optimized fine-grained feature extraction. Trained on a dataset of 600 pork images graded by microbial cell concentration, BBSNet achieved an average accuracy of 96.36% in a challenging 5-way 80-shot task. This approach significantly reduces data dependency while maintaining high accuracy, presenting a viable solution for cost-effective real-time pork quality monitoring. This work introduces a novel framework that connects laboratory freshness indicators to industrial applications in data-scarce conditions. Future research will investigate its extension to various food types and optimization for deployment on portable devices. Full article

Listeria monocytogenes is one of the most significant foodborne pathogens capable of causing bacteremia. In the present study, a total of 138 pork meat samples were collected from 46 randomly selected butcher shops selling raw and ready-to-eat products in La Plata, Buenos Aires, Argentina. Samples were processed according to internationally recognised standards, resulting in a positivity rate of 32.6%. This constitutes the first report of L. monocytogenes in fresh pork meat in the region and provides a strong foundation for control strategies of this microorganism in fresh pork meat retailers in Argentina. Full article

In this study, aligned with the principles of the circular economy and sustainability, novel eugenol@natural zeolite (EG@NZ) and citral@natural zeolite (CT@NZ) nanohybrids were developed. These nanohybrids were successfully incorporated into a pork gelatin (Gel)/glycerol (Gl) composite matrix using an extrusion–compression molding method to produce innovative active packaging films: Gel/Gl/xEG@NZ (where x = 5, 10, and 15%wt.) and Gel/Gl/xCT@NZ (where x = 5 and 10%wt.). All films exhibited zero oxygen barrier properties. Release kinetic studies showed that both EG@NZ and CT@NZ nanohybrids adsorbed up to 58%wt. of their respective active compounds. However, EG@NZ exhibited a slow and nearly complete release of eugenol, whereas CT@NZ released approximately half of its citral content at a faster rate. Consequently, the obtained Gel/Gl/xEG@NZ films demonstrated significantly higher antioxidant activity as measured by the 2,2-diphenyl-1-picrylhydrazylradical (DPPH) assay and superior antibacterial effectiveness against Escherichia coli and Listeria monocytogenes compared to their CT-based counterparts. Overall, the Gel/Gl/xEG@NZ films show strong potential for applications as active pads for fresh pork ham slices, offering zero oxygen permeability, enhanced antioxidant and antibacterial properties, and effective control of total viable count (TVC) growth, maintaining a low and steady rate beyond the 10th day of a 26-day storage period. Full article

Determining the technological quality of fresh meat pieces is essential in the meat industry to ensure the production of high-quality products. For this purpose, nuclear magnetic resonance (NMR) is a non-destructive and non-invasive technique that appears as an alternative to traditional methodologies. The objective of this work is to determine the potential of magnetic resonance imaging (MRI) and time-domain (TD-NMR) relaxometry for determining the physicochemical characterization of fresh hams with different industrial destinations (both fresh and cured products, such as dry-cured ham). For this study, the biceps femoris, semimembranosus, and semitendinosus muscles of 20 fresh hind legs from white pigs, classified into four categories according to their fat content, were analyzed. The semitendinosus muscle was selected as a model, and positive and negative correlations were obtained between different physicochemical parameters and the longitudinal (T1) and transverse (T2) relaxation times obtained by MRI and TD-NMR. Regression models using T1 and T2 were also developed to predict the muscle water-holding capacity (WHC) and drip loss, using high, medium, and low magnetic field NMR (R² > 0.80). Therefore, MRI and TD-NMR could be considered as highly suitable and accurate non-destructive techniques for the WHC determination in the meat industry. Full article

A ratiometric fluorescent film with high gas sensitivity and stability was developed using electrospinning technology for monitoring food spoilage. 5(6)-Carboxyfluorescein (5(6)-FAM) was used as the indicator, combined with the internal reference Rhodamine B (RHB), to establish a composite ratiometric fluorescent probe (FAM@RHB). The hydrophobic fluorescent films were fabricated by incorporating FAM@RHB probes into polyvinylidene fluoride (PVDF) at varying molar ratios through electrospinning. The FR-2 film with a 2:8 ratio of 5(6)-FAM to RHB exhibited the best performance, demonstrating excellent hydrophobicity with a water contact angle (WCA) of 113.45° and good color stability, with a ΔE value of 2.05 after 14 days of storage at 4 °C. Gas sensitivity tests indicated that FR-2 exhibited a limit of detection (LOD) of 0.54 μM for trimethylamine (TMA). In the application of monitoring the freshness of pork and beef at 4 °C, the fluorescence color of the FR-2 film significantly changed from orange–yellow to green, enabling the visual monitoring of meat freshness. Hence, this study provides a new approach for intelligent food packaging. Full article

Nowadays, there is a great concern about the prevalence of multidrug-resistant bacteria in meat, especially Staphylococcus aureus resistant to methicillin (MRSA). The aim of this work was to evaluate the microbiological quality of fresh pork meat and the presence and resistance of S. aureus and other Staphylococcus spp., Mammaliicoccus spp., and Macrococcus spp. to methicillin and other antibiotics. A total of 39 fresh pork meat samples were analyzed. MRSA was isolated from one sample, being resistant to eight antimicrobial families, including aminoglycosides, β-lactams, lincosamides, macrolides, sulfonamides, tetracycline, and others such as fusidic acid, and mupirocin. Also, other multidrug-resistant strains with resistance to 5 or 6 antimicrobial families were isolated including Staphylococcus succinus, Mammaliicoccus sciuri, and Macrococcus caseolyticus. Additional measures should be taken to control MRSA in pork meat. Full article

In the context of the circular economy, the valorization of bio-derived waste has become a priority across various production sectors, including food processing and packaging. Gelatin (Gel), a protein which can be recovered from meat industry byproducts, offers a sustainable solution in this regard. In this study, pork-derived gelatin was used to develop novel edible active packaging films, designed for meat products. Glycerol (Gl) was used as a plasticizer. Two types of montmorillonite-based nanohybrids were employed as both reinforcing agents and carriers of antioxidant/antibacterial compounds: eugenol-functionalized montmorillonite (EG@Mt) and citral-functionalized montmorillonite (CT@Mt). The active films were formulated as Gel/Gl/xEG@Mt and Gel/Gl/xCT@Mt, where x = 5, 10, or 15 wt.%. Controlled-release kinetics showed that EG@Mt released up to 95% of its adsorbed eugenol, whereas CT@Mt released up to 55% of its adsorbed citral. The films were evaluated using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay and tested for antibacterial activity against Escherichia coli and Listeria monocytogenes. Results demonstrated that the Gel/Gl/xEG@Mt films exhibited superior antioxidant and antibacterial performance compared to the Gel/Gl/xCT@Mt films. All formulations were impermeable to oxygen. Although the incorporation of EG and CT slightly reduced cell viability, values remained above 80%, indicating non-toxicity. In conclusion, the film containing 15 wt.% EG@Mt achieved an oxygen transmission rate of zero, an effective concentration (EC₆₀) of 9.9 mg/L to reach 60% antioxidant activity, and reduced E. coli and L. monocytogenes populations by at least 5.8 log CFU/mL (p < 0.05), bringing them below the detection limit. Moreover, it successfully extended the shelf life of fresh minced pork by two days. Full article

The quality of raw meat is important for community health as its freshness is crucial to preventing foodborne illnesses. In the United States, the related illness cases were 9.4 million cases with 55,961 hospital admissions and 1351 deaths annually. This underscores the urgent need for improved meat quality monitoring. This study aims to develop an electronic nose (E-nose) that can differentiate between frozen–thawed and fresh pork meat samples, thereby enhancing food safety. We designed the E-nose using MQ series gas sensor array with temperature and humidity sensors, and an Arduino Uno microcontroller. Sensors were calibrated for accurate data collection. An adaptive support vector machine (ASVM) was used for data classification. We evaluated the model’s accuracy using a confusion matrix. The ASVM model exhibited robust performance, achieving an accuracy of 88%. Its performance was evaluated with recall, F1 scores, and precision. To further enhance the model’s performance, future studies are mandated to integrate additional gas sensors, increase sample sizes, advance data preprocessing techniques, and explore different machine learning algorithms or ensemble methods. Full article

Films formulated with gelatin and chitosan (GL/CH) or chitosan (CH), without or with 0.3% and 0.5% concentrations of rice bran extract (RBE), have been developed. The migrations of rice bran extract and the antioxidant and antimicrobial properties in vitro have been assessed. The effects of the film formulations in maintaining color stability, oxidative status and microbial loads on fresh pork meat during 9 days of refrigerated storage were studied. For the films, releases of γ-oryzanol only were observed in low polarity simulant. The highest migrations and antioxidant activity were related to gelatine films, enhanced with the addition of rice bran extract. Only chitosan films showed antimicrobial activity in vitro against Escherichia coli and Listeria innocua, reaching decreases of 7.68 and 8.06 Log CFU at 72 h, respectively. Both gelatin/chitosan and chitosan films prevented the color changes in meat during storage, preventing the paleness, and chitosan films also provoked an increment of redness until 2.88 units of CIE b* at day 9. The films did not prevent either lipid or protein oxidation in meat, despite the rice bran extract inclusion, even increasing the lipid oxidations with chitosan films. However, all films helped to control the microbial counts in meat throughout all the storage, with chitosan being the most effective films, especially with the addition of RBE. Overall, gelatin/chitosan and chitosan films offer a sustainable alternative for fresh pork meat packaging. Full article

This research developed a biodegradable absorbent pad using polybutylene adipate terephthalate (PBAT) and thermoplastic starch (TPS) films, combined with hairy basil (Ocimum basilicum) seed powder (HBP) to extend the shelf life of fresh pork during cold storage. To form the biocomposite film, PBAT was blended with TPS in ratios of 100:0, 90:10, 70:30, and 50:50. The PBAT:TPS ratio of 70:30 (PB7T3) was the most suitable in terms of mechanical properties and water permeation. Therefore, PB7T3 was selected to fabricate the absorbent pad for extending the shelf life of fresh pork during cold storage. For the storage test, 100 g of pork pieces was placed in PET trays (12 cm × 12 cm), each containing a different absorbent: the control (no pad), a commercial absorbent pad, and the PB7T3 absorbent pad. The pork samples were stored at 4 °C for 8 days and analyzed for color change, total plate count (TPC), total volatile basic nitrogen (TVB-N), pH, and drip loss on days 0, 2, 4, 6, and 8. The results indicated that the PB7T3 absorbent pad effectively extended the shelf life of fresh pork compared to the control, with no significant difference compared to the commercial absorbent pad made from plastic. This research opens new avenues for developing sustainable absorbent pads, contributing to reduced reliance on conventional non-biodegradable plastics. Full article