Understanding spoilage microbial community and spoilage mechanisms in foods of animal origin

Sodium chloride reduction in meat processing: Microbial shifts, spoilage risks, and metagenomic insights

This review evaluated the impact of sodium chloride (NaCl) reduction or substitution on the microbial ecology of meat products, with a focus on how these changes affect shelf life and safety. Reducing NaCl in fresh meat products promotes the growth of psychrotrophic spoilage bacteria, such as Pseudomonas sp., which thrive at low temperatures, and mesophilic pathogens like Escherichia coli and Staphylococcus aureus, particularly under inadequate storage conditions. In cured and fermented meats, such as salami, lowering NaCl levels disrupts the balance of salt-tolerant microorganisms, notably lactic acid bacteria (LAB) and coagulase-negative staphylococci, potentially leading to increased spoilage and pathogen proliferation. In smoked meats, the combination of reduced NaCl and altered microbial ecology, including a shift toward LAB dominance, may weaken the inhibitory effects on spore-forming bacteria like Clostridium botulinum. Additionally, using metagenomics, we explore the shifts in microbial communities observed in studies involving meat, revealing critical insights into the composition and diversity of bacteria in meat products, as well as the gaps in research on the impact of NaCl reduction and/or substitution on the microbiota. This review provides a comprehensive understanding of these microbial shifts, highlighting the distinct responses of psychrotrophic, mesophilic, and LAB groups to NaCl modification and the need to understand the effects of these alternatives on the meat product microbiome, as well as the neglected microorganisms that can affect the quality and safety of these products.

Development of a novel chemosensor for photodynamic antimicrobial and fluorescence-colorimetric dual-mode sensing in food preservation and spoilage process monitoring

The integration of photodynamic antimicrobial with multimodal sensing technologies offers substantial potential applications across diverse stages of food production, storage, and transportation. Here, we have developed a novel colorimetric/fluorescent dual-mode sensing chemosensor, TIDOH, with photodynamic antimicrobial capabilities. TIDOH was synthesized by coupling triphenylamine, which exhibits photodynamic properties, with pH-sensitive reactive groups through Knoevenagel condensation. Under acidic conditions, TIDOH opens its ring to form a conjugated structure, while under alkaline conditions, it closes the ring, resulting in a blue shift in fluorescence emission. This behavior, confirmed by DFT calculations and fluorescent methods, allows TIDOH to detect volatile amines through significant color changes, aiding visual spoilage monitoring. Additionally, in vitro studies revealed TIDOH's photodynamic antimicrobial activity. By integrating it with biocompatible carboxymethyl chitosan and sodium alginate, we developed an antimicrobial film that effectively preserves strawberries. This research not only underscores TIDOH's utility in food safety but also advances food preservation technology.

Battery-Free, Stretchable, and Autonomous Smart Packaging

In the food industry, innovative packaging solutions are increasingly important for reducing food waste and contributing to global sustainability efforts. However, current food packaging is generally passive and unable to adapt to changes in the food environment in real time. To address this, a battery-less and autonomous smart packaging system is developed that wirelessly powers closed-loop sensing and release of active compounds. This system integrates a gas sensor for real-time food monitoring, a Near-Field Communication (NFC) antenna, and a controlled release of active compounds to prevent quality deterioration in the complex food environment. The ability of the developed smart packaging system is demonstrated, to continuously monitor the freshness of fish products and to trigger the release of active compounds when the food starts to spoil. The system is able to extend the shelf-life of the food product up to 14 days, due to the controlled release of antioxidant and antibacterial compounds. The system can pave the way toward an Internet of Things solution that addresses protection, active prevention of food spoilage, and sustainability, facing all the current challenges of the food packaging industry.

Regulation of a chromenylium fluorophore with a built-in recognition site for the detection of sulfite

A double charged cationic pyridinium-fused chromenylium analogue DMCQ with an acceptor-π-acceptor (A-π-A) electronic structure was designed and prepared for the sensitive and selective detection of SO32-. Undergoing a Michael addition reaction with SO32- at the built-in pyridinium moiety in the chromenylium fluorophore, the π-electron structure of the chromenylium skeleton transferred from an (A-π-A) to (A-π-D) system along with a prominent fluorescence enhancement. Based on this specific addition reaction, the DMCQ probe exhibits high selectivity for the detection of SO32- over other biologically related species within a wide pH range (4-10). As the highly electron-deficient nature of the pyridinium-fused chromenylium accelerated the reaction with SO32-, the probe presented a rapid response time (60 s), together with high sensitivity (33 nM). Besides, DMCQ could not only image SO32- in living cells but also monitor SO32- in food and water samples with a satisfactory recovery of 81.30-112.89%.

Revolutionizing agroindustry: Towards the industrial application of antimicrobial peptides against pathogens and pests

Antibiotics are essential chemicals for medicine and agritech. However, all antibiotics are small molecules that pathogens evolve antimicrobial resistance (AMR). Alternatively, antimicrobial peptides (AMPs) offer potential to overcome or evade AMR. AMPs provide broad-spectrum activity, favourable biosafety profiles, and a rapid and efficient mechanism of action with low resistance incidence. These properties have driven innovative applications, positioning AMPs as promising contributors to advancements in various industrial sectors. This review evaluates the multifaceted nature of AMPs and their biotechnological applications in underexplored sectors. In the food industry, the application of AMPs helps to suppress the growth of microorganisms, thereby decreasing foodborne illnesses, minimizing food waste, and prolonging the shelf life of products. In animal husbandry and aquaculture, incorporating AMPs into the diet reduces the load of pathogenic microorganisms and enhances growth performance and survival rates. In agriculture, AMPs provide an alternative to decrease the use of chemical pesticides and antibiotics. We also review current methods for obtaining AMPs, including chemical synthesis, recombinant DNA technology, cell-free protein synthesis, and molecular farming, are also reviewed. Finally, we look to the peptide market to assess its status, progress, and transition from the discovery stage to benefits for society and high-quality products. Overall, our review exemplifies the other side of the coin of AMPs and how these molecules provide similar benefits to conventional antibiotics and pesticides in the agritech sector.

The polysaccharide-based nanoemulsions: Preparation, mechanism, and application in food preservation-A review

The stability and bioavailability of antioxidant, antibacterial, and other bioactive substances could be improved through nanoemulsion systems, as a result, nanoemulsion technology has become popular in food preservation. Polysaccharides are green polymers, their renewability, richness, safety, and functionality determine broad application prospects. Polysaccharide-based nanoemulsion coatings with good waterproofness, and mechanical and biological properties are found to effectively prevent or delay water loss, respiration, gas exchange, and microbial corruption of fruits, vegetables, and meat products, and they will be an important innovative technology for sustainable development in the future. The structural and functional properties of polysaccharides that could stabilize nanoemulsions have been discussed, and the preparation methods, physicochemical properties, stability, and formation mechanism of nanoemulsions have been summarized in this review. In addition, the preparation methods of polysaccharide-based nanoemulsion coatings are summarized, the application and preservation mechanisms in fruits, vegetables, and meat products have been introduced, and future perspectives have been discussed. At present, the related researches mainly focus on the bactericidal activity and the sensory quality of food products, while the in-depth research is unclear, this review provides ideas for the subsequent research on polysaccharide-based nanoemulsions for food preservation.

Microbial and Quality Changes of Seabream Fillets Processed with Cold Plasma During Refrigerated Storage

Cold plasma (CP) is a non-thermal technology, successfully used to decontaminate and extend the shelf-life of various foods. However, CP can cause quality deterioration in sensitive matrices, such as fish products. This research aimed to evaluate the effect of CP treatment obtained using different gas mixtures (80% Ar/20% O2, or 80% N2/20% O2) with a surface dielectric barrier discharge (SDBD) on the decontamination of spoilage microflora, the main quality indices and the sensory acceptability of seabream (Spaurus aurata L.) fillets during refrigerated storage. At the beginning and at the end of the shelf life, lipid and protein oxidation indices and the fatty acid profile were evaluated. Results showed that, despite a low initial microbial decontamination (0.2-0.3 Log CFU/g), an inhibition of the growth of the main spoilage bacteria was observed resulting in an increase of the microbiological shelf life of around 40% for both treatments. Although a slight increase in lipid and protein oxidation was observed (up to around 5 mg MDA/kg and 4 nmol/mg of protein for TBARs and carbonyl content respectively), the sensory acceptability was higher for plasma treated samples, while the fatty acid profile was not affected and only a slight variation in the surface colour was observed (L* value increase by 3 points), confirming that CP could represent an interesting strategy to extend the shelf life of seafood products with minimal impact on quality and nutritional value.

Crosslinked protein-polysaccharide nanocomposite coating for pork preservation: Impact on physicochemical properties and microbial structure

Edible films are significant in prolonging the shelf life of meat products. Herein, we prepared some edible coatings (EW/TNPCSs) based on egg white/chitosan/pectin as polymer matrix, containing tannic acid-nisin composite nano-crosslinker with antibacterial-antioxidant activities. The results of preservation indicated that the prepared EW/TNPCSs reduced the water loss of chilled pork and delayed the changes of taste, texture and surface color. At the end of the 12-day storage period, the content of TVB-N and carbonyl as well as the pH of EW/TNPCS5 chilled pork decreased by 33.75 %, 96.61 % and 7.09 %, respectively, and colony count decreased by 17.71 % compared to the control. Additionally, EW/TNPCSs inhibited the richness and diversity of spoilage dominant bacteria (Myroides, Acinetobacter, etc.), which were positively regulated by physicochemical indicators such as saltiness and abundance of bacteriostatic materials-coated chilled pork. It will provide a practical basis for the application of EW/TNPCSs coatings in the preservation of chilled pork.

Growth and Diversity of Spoiling and Foodborne Bacteria in Poultry Hamburgers in Modified Atmosphere and with Sulfites During Shelf Life

Poultry meat is the most consumed meat worldwide due to its low fat content, sensory qualities, and affordability. However, its rapid spoilage, especially when minced for products like hamburgers, is a challenge. Strategies such as sulfite addition or modified-atmosphere packaging (MAP) can help control spoilage and microbial growth. This study evaluated both approaches by analyzing bacterial development in poultry hamburgers through total viable counts and MALDI-TOF identification, combining food-pathogens detection. The addition of 5 mg/kg sulfites had a limited effect, whereas increasing CO2 levels in the packaging significantly extended the shelf life by reducing the bacterial growth rates and prolonging the lag phases. The most affected bacteria were aerobic mesophilic and psychrotrophic bacteria, as well as Brochothrix thermosphacta. Carnobacterium spp. dominated the aerobic mesophilic group, while Enterobacter spp. was prevalent in Enterobacteriaceae and aerobic mesophilic isolates, highlighting its role in spoilage. Hafnia alvei was also relevant in the final spoilage stages. These results suggest the importance of these bacteria in poultry hamburger decay and demonstrate that MAP is an effective method to delay spoilage.

Listeria monocytogenes colonises established multispecies biofilms and resides within them without altering biofilm composition or gene expression

Listeria (L.) monocytogenes can survive for extended periods in the food producing environment. Here, biofilms possibly provide a niche for long-term survival due to their protective nature against environmental fluctuations and disinfectants. This study examined the behaviour of a L. monocytogenes ST121 isolate in a multispecies biofilm composed of Pseudomonas (P.) fragi, Brochothrix (B.) thermosphacta, and Carnobacterium (C.) maltaromaticum, previously isolated from a meat processing facility. The composition of the biofilm community and matrix, and transcriptional activity were analysed. L. monocytogenes colonised the multispecies biofilm, accounting for 6.4 % of all total biofilm cells after six hours. Transcriptomic analysis revealed 127 significantly up-regulated L. monocytogenes genes compared to the inoculum, including motility, chemotaxis, iron, and protein transport related genes. When comparing the differentially expressed transcripts within the multispecies biofilm with and without L. monocytogenes, only a cadmium/zinc exporting ATPase gene in C. maltaromaticum was significantly upregulated, while the other 9313 genes in the biofilm community showed no significant differential expression. We further monitored biofilm development over time (6, 24 hours and 7 days). P. fragi remained the dominant species, while L. monocytogenes was able to survive in the multispecies biofilm accounting for 2.4 % of total biofilm cells after 7 days, without any significant changes in its abundance. The presence of L. monocytogenes did neither alter the biofilm community nor its matrix composition (amount of extracellular DNA, carbohydrates, and protein). Our data indicate that L. monocytogenes resides in multispecies biofilms, potentially increasing survival against cleaning and disinfection in food processing environments, supporting persistence.

Frost-resistant hydrogel colorimetric sensing array for accurate detection of foodborne pathogens in cold chain systems

The rapid and precise identification of foodborne pathogens in low-temperature environments is critically important yet challenging, particularly within the cold chain system. This study introduces a frost-resistant colorimetric sensing array (FR-CSA), based on polyvinyl alcohol/polyacrylamide/lithium chloride (PVA/PAM/LiCl) double network (DN) hydrogels, designed for the detecting and classifying foodborne pathogens at 4 °C and -20 °C. The integration of LiCl into the PVA/PAM DN hydrogels results in a dense 3D nano-network that significantly lowers the freezing point, enhancing the sensing functionality at subzero temperatures, addressing a critical gap where conventional CSAs fail to perform. The FR-CSA demonstrates high performance, accurately responding to twelve common volatile organic compounds (VOCs) emitted by pathogens and generating distinctive color response patterns. Employing principal component analysis (PCA) and linear discriminant analysis (LDA), the FR-CSA effectively identifies four prevalent low-temperature foodborne pathogens: Staphylococcus aureus, Listeria monocytogenes, E. coli O157:H7, and Salmonella. Additionally, the FR-CSA has been successfully applied to a chicken breast meat model, confirming its efficacy across the tested temperature range. This work presents an innovative approach for pathogen detection in critical low-temperature settings of cold storage, offering significant potential contributions to food preservation within the cold chain system.

High pressure processing of hummus: Enhancing microbial safety and stability, and reducing lipid oxidation

Hummus provides an ideal environment for microbial growth. The objectives of this study were to evaluate the effect of high-pressure processing (HPP) on i) microbial safety/quality, ii) physical/chemical properties, and iii) sensory characteristics of hummus. Uninoculated and hummus inoculated with Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes were subjected to HPP at 350 MPa for 1-5 min. After treatment, the D-value of the pathogens was calculated and uninoculated samples were stored for up to 28 d at 4 and 10 °C and total microbial counts (TMC) were enumerated. Thiobarbituric acid reactive substances (TBARS), colour, textural and rheological properties and sensory characteristics of hummus were also analysed. The D10-value for Salmonella spp., E. coli O157:H7 spp. and L. monocytogenes were 2.10 ± 0.13, 1.48 ± 0.08, and 3.77 ± 0.36 min, respectively. As compared to the control, HPP for 1, 2, 3, 4, and 5 min instantly decreased TMC on average by 0.7, 1.2, 1.6, 1.4 and 1.8 log cfu/g, respectively. The shelf life of hummus in this study after an HPP treatment of 350 MPa for 2-5 min was 28 d at 4oC and one week at 10 °C, while it was 14 d and 7 d in the control samples, respectively. HPP decreased TBARS but did not significantly change hummus lightness, greenness, and yellowness. HPP enhanced the gel strength and viscoelastic properties of hummus without compromising its sensory qualities. Thereby, HPP at 350 MPa for 1-5 min can be effective and adopted by producers.

Integrating transfer learning and spectroscopy for enhanced pork spoilage assessment using correlation analysis

Accurate Total Viable Count (TVC) detection is vital for food quality monitoring. In this study, we investigated the feasibility of using visible near-infrared (VNIR) spectroscopy (400-1000 nm) combined with transfer learning (TL) to track the chemical spoilage of pork. The base models developed using the full band for pork TVC, total volatile basic nitrogen, pH, and color showed predictability; the correlation coefficient of prediction set (RP) for all models ranged from 0.821 to 0.916; and the root mean square error of prediction set (RMSEP) of the TVC model was 0.617 (lg CFU/g). A correlation analysis of the different indexes of pork was carried out to optimize the TVC calibration model. Different TL methods for TVC optimization were designed. The results showed that multiple correlation chain stacking-partial least squares performed best with RP, RMSEP, and the relative percent deviation of 0.947, 0.425 lg CFU/g, and 2.355, respectively, the RMSEP of TVC was reduced by 31.12 % as compared to the base model. This study demonstrated the possibility of combining the VNIR spectroscopy system with TL to monitor the degree of meat's chemical spoilage.

Impacts of chitosan/pullulan/carvacrol film on the quality and microbial diversity of refrigerated goat meat

In this study, our previously prepared chitosan/pullulan film (CS/PU) and chitosan/pullulan/carvacrol film (CS/PU/CAR) were applied to goat meat preservation, the dynamic changes in quality and microbial communities of goat meat during chilled storage (4 °C) were investigated, and the fresh-keeping effects of the two biodegradable antibacterial films on goat meat were comprehensively evaluated. The results showed that when the goat meat was wrapped with CS/PU or CS/PU/CAR films during chilled storage, the total plate count and total volatile basic nitrogen (TVB-N) could be inhibited significantly, but the CS/PU/CAR film has a better fresh-keeping effect. Furthermore, during the chilled storage of goat meat, CS/PU/CAR film also could inhibit the production of alcohol compounds and the growth of Pseudomonas spp., thereby slowing down the meat's deterioration and extending the goat meat's shelf life to about 13 days. This study can provide a reference for the application of active packaging film of fresh goat meat.

Integrated microbiome and metabolomics analysis of spoilage characteristics of modified atmosphere packaged pork

The interactions between pork microbial communities and metabolites in modified atmosphere packaged (MAP) storage remain unclear. This study exposed the core microbial communities and metabolite profiles during refrigerated pork storage under MAP and illuminated the relationship between them by high-throughput sequencing and non-targeted metabolomics to comprehend the spoilage mechanism induced by microbial activity in MAP pork during storage. The results showed that Pseudomonas and Serratia were the predominant spoilage bacteria in the preliminary stages of refrigerated pork, while Brochothrix gradually dominated in the final stages of storage. 76 differential metabolites were identified from 822 metabolites, consisting of small-molecule metabolites including glycerophospholipids, bitter amino acids, amines, and nucleotides. The metabolic pathways involved in these metabolites were 10 metabolic pathways inclusive of purine metabolism, nucleotide metabolism, and glycerophospholipid metabolism. Correlation results revealed that bacterial genera like Pseudomonas, Brochothrix, Stenotrophomonas, Acinetobacter, and Aeromonas were significantly correlated with metabolites such as lipids, organic acids and nucleotides. These findings enhance our understanding of the spoilage mechanism of refrigerated pork stored in MAP.

Postbiotics in the Bakery Products: Applications and Nutritional Values

In recent years, the consumption of postbiotics has gained significant attention due to their potential health benefits. However, their application in the bakery industry remains underutilized. This review focuses on recent advances in the use of postbiotics, specifically the metabolites of lactic acid bacteria, in bakery products. We provide a concise overview of the multifaceted benefits of postbiotics, including their role as natural antioxidants, antimicrobials, and preservatives, and their potential to enhance product quality, extend shelf-life, and contribute to consumer welfare. This review combines information from various sources to provide a comprehensive update on recent advances in the role of postbiotics in bakery products, subsequently discussing the concept of sourdough as a leavening agent and its role in improving the nutritional profile of bakery products. We highlighted the positive effects of postbiotics on bakery items, such as improved texture, flavor, and shelf life, as well as their potential to contribute to overall health through their antioxidant properties and their impact on gut health. Overall, this review emphasizes the promising potential of postbiotics to revolutionize the bakery industry and promote healthier and more sustainable food options. The integration of postbiotics into bakery products represents a promising frontier and offers innovative possibilities to increase product quality, reduce food waste, and improve consumer health. Further research into refining techniques to incorporate postbiotics into bakery products is essential for advancing the health benefits and eco-friendly nature of these vital food items.

Lignin-containing cellulose nanocrystals from maple leaves: A natural Pickering emulsion stabilizer for food preservation

Cellulose nanocrystals have been obtained from maple leaves for stabilizing Pickering emulsions, but a chemical modification is required to improve hydrophobicity and the yield is relatively low due to the removal of non-cellulose components. Herein, lignin was retained while isolating cellulose from maple leaves, and the prepared lignin-containing cellulose nanocrystals (LCNCs) were applied as natural Pickering emulsion stabilizers. Rod-like shaped LCNCs with tunable lignin contents had suitable hydrophobicity and high aspect ratios, resulting in long-term stability of LCNC-stabilized Pickering emulsions. The obtained emulsions provided good encapsulation and protection of cinnamaldehyde, and the controlled release of cinnamaldehyde promoted sustained antibacterial efficacy. Both direct-contact and non-contact preservation modes were investigated for shrimp preservation, where headspace release of cinnamaldehyde from emulsions at non-contact mode was more effective in inhibiting bacterial proliferation compared to direct-contact (spray-coating) mode. This work demonstrates the feasibility of developing value-added LCNCs from maple leaves as sustainable Pickering emulsion stabilizers.

Aeration promotes Proteobacteria over Firmicutes in macerated food waste, resulting in superior anaerobic digestion efficiency

Aeration is a common pretreatment method to enhance biogas production via anaerobic digestion of waste organic feedstocks such as unused food. While impacts on downstream anaerobic digestion have been intensively investigated, the consequence of aeration on the microbial community in food waste has not been characterized. Food waste has a low pH resulting from the dominance of lactic acid bacteria within the Firmicutes phylum. This excludes other phylotypes with a higher potential to hydrolyse complex biopolymers in food waste. In this study, we reveal that aeration of macerated food waste results in a dramatic shift away from Firmicutes towards dominance of Proteobacteria that are better known for extracellular enzyme production. Given that hydrolysis is the rate limiting step in anaerobic digestion, this explains why aeration improves the efficiency of biogas production from food waste. The discovery that Proteobacteria dominate microbial communities in aerated food waste opens up opportunities to manipulate extracellular enzyme production through gene expression mechanisms common among Proteobacteria such as quorum sensing.

Characterization of a novel phage SPX1 and biological control for biofilm of Shewanella in shrimp and food contact surfaces

Shewanella putrefaciens, commonly found in seafood, forms tenacious biofilms on various surfaces, contributing to spoilage and cross-contamination. Bacteriophages, owing to their potent lytic capabilities, have emerged as novel and safe options for preventing and eliminating contaminants across various foods and food processing environments. In this study, a novel phage SPX1 was isolated, characterized by a high burst size (43.81 ± 3.01 PFU/CFU) and a short latent period (10 min). SPX1 belongs to the Caudoviricetes class, exhibits resistance to chloroform, and sensitivity to ultraviolet. It shows stability over a wide range of temperatures (30-50 °C) and pH levels (3-11). The genome of phage SPX1 consists of 53,428 bp with 49.72 % G + C composition, and lacks tRNAs or virulence factors. Genome analysis revealed the presence of two endolysins, confirming its biofilm-removal capacity. Following the treatment of shrimp surface biofilm with the optimal MOI of 0.001 of phage SPX1 for 5 h, the bacterial count decreased by 1.84 ± 0.1 log10 CFU/cm2 (> 98.5 %). Biofilms on the surfaces of the three common materials used in shrimp processing and transportation also showed varying degrees of reduction: glass (1.98 ± 0.01 log10 CFU/cm2), stainless steel (1.93 ± 0.05 log10 CFU/cm2), and polyethylene (1.38 ± 0.1 log10 CFU/cm2). The study will contribute to phage as a novel and potent biocontrol agent for effectively managing S. putrefaciens and its biofilm, ensuring a reduction in spoilage bacteria contamination during the aquaculture, processing, and transportation of seafood products.

LED induced non-thermal preservation of muscle foods: A systematic review

LED technology has emerged as a promising non-thermal preservation method for highly perishable muscle foods like meat and fish. Muscle foods are most susceptible to spoilage due to their high moisture content and nutrient density, which create an ideal environment for microbial growth, chemical oxidation, and enzymatic activity, which negatively alter their quality. LED treatment offers an effective solution by significantly reducing microbial loads and extending shelf life without adversely affecting sensory and nutritional properties. Specific wavelengths of LED light induce microbial inactivation through mechanisms like DNA damage, lipid oxidation, and protein alteration. Studies have shown that LED treatment can preserve the fresh-like quality of muscle foods by mitigating common spoilage processes. The advantages of LED technology include its non-thermal nature, ability to integrate with other preservation methods, and controllability in terms of intensity and wavelength. This enables for tailored applications based on food type and spoilage risks. As consumer demand grows for safe, chemical-free food options, LED technology addresses this need while enhancing food safety and quality. Further research is encouraged to optimize LED applications in various muscle food preservation contexts. With its exceptional ability to produce DNA damage in bacteria, inactivate enzymes, and malfunction biological activities, LED could serve as an inexpensive processing intervention to safeguard the quality of meat and seafood products. This review underscores the potential of LED technology as a promising alternative to traditional preservation methods for decontamination of muscle food.

A novel fluorescence platform for portable and visual monitoring of meat freshness

Biogenic amines (BAs) are crucial markers of meat spoilage. Developing practical and effective BAs detection methods is essential for monitoring meat freshness and ensuring daily consumption safety. This study prepared several naphthalene-based fluorescent compounds to visually monitor meat freshness in real-time. These probes show a colorimetric fluorescence response to putrescine and cadaverine (typical spoilage indicators) through nucleophilic addition/elimination reaction. The detectability of these probes can be optimized by altering the electronegativity and substitution position of the recognition group. Among these compounds, 2-((6-(4-(diphenylamino)phenyl)naphthalen-2-yl)methylene)malono nitrile (TNMA) demonstrated exceptional sensing performance toward putrescine and cadaverine, including high-contrast fluorescence color transition (red to blue), rapid response times (∼30 s), high selectivity and sensitivity (detection limit for putrescine: 2.69 ppm, cadaverine: 6.11 ppm). Furthermore, the B/R values of TNMA test strips output by RGB analysis presented a linear correlation with total volatile basic nitrogen (TVBN, an international standard for evaluating food spoilage) values in pork. Based on this correlation, we utilized smartphone applications to construct an intelligent evaluation system, enabling visual monitoring of pork, chicken, and shrimp freshness under various storage conditions. The TNMA-based system offers a reliable platform for real-time, portable and visual monitoring of meat freshness for consumers and suppliers in the food industry.

Nano-Coating Loaded With Leaf and Flowers of Pelargonium graveolens Plant Extract Stabilized With Fenugreek Seed Gum and Soy Protein Isolate in Increasing the Shelf Life of Mutton Fillet

In this study, the extract of leaf and flower of Pelargonium graveolens was obtained using an ultrasonic-assisted extraction method. The extraction yield and the content of phenolic, flavonoid, and flavonol compounds in the flower extract were higher (13.93%, 74.97 mg GAE g DM-1, 31.93 mg QE g DM-1, and 9.08 mg QEE g DM-1) than leaf extract (10.69%, 67.46 mg GAE g DM-1, 23.04 mg QE g DM-1, and 11.34 mg QEE g DM-1). Both extracts demonstrated antioxidant properties in tests involving the scavenging of DPPH radicals and the ferric reduction assay. Extracts exhibited antimicrobial properties. MIC of flower extract against Staphylococcus aureus and Escherichia coli were 2500 and 5000, while MBC of leaf extract were 15,000, and 20,000 ppm, respectively. The concentration of 2000 ppm of extracts was encapsulated in fenugreek seed gum (FSG) and soy protein isolate (SPI) produced by the emulsification method. All nano-coatings exhibited a nanometric size range between 172.75 to 255.21 nm, and encapsulation efficiency higher than 80.0% (80.82% to 89.59%). The application of nano-coatings significantly reduced microbial counts and delayed lipid oxidation in mutton meat during 12 days of cold storage at 4°C, enhancing meat quality and extending shelf life. The inclusion of bioactive compounds like polyphenols in the coatings contributed to antimicrobial and antioxidant effects, decreasing pH levels and preventing spoilage. The findings indicated that the combination of edible FSG and SPI as wall materials with 2000 ppm of P. graveolens extract demonstrated efficacy in implementation bacterial growth and lipid oxidation in fresh mutton meat.

Antimicrobial Peptides from Porcine Blood Cruor Hydrolysates as a Promising Source of Antifungal Activity

Porcine blood, a significant byproduct of the pork industry, represents a potential source of antimicrobial peptides (AMPs). AMPs offer a promising alternative to chemical antimicrobials, which can be used as natural preservatives in the food industry. AMPs can exhibit both antibacterial and/or antifungal properties, thus improving food safety and addressing the growing concern of antibiotic and antifungal resistance. The objective of this study was to evaluate the antimicrobial activity of potential AMPs previously identified from porcine cruor hydrolysates. To this end, a total of sixteen peptides were chemically synthesized and their antimicrobial activities (antibacterial, anti-mold, and anti-yeast) were evaluated using microtitration and agar well diffusion methods against a wide range of microorganisms. Five new peptide sequences demonstrated antifungal activity, with Pep5 (FQKVVAGVANALAHKYH), an alpha-helix peptide, exhibiting the most promising results. Pep5 demonstrated efficacy against nine of the eleven fungal isolates, exhibiting low minimum inhibitory concentrations (MICs) and a fungicidal effect against key spoilage fungi (Rhodotorula mucilaginosa, Debaryomyces hansenii, Candida guilliermondii, Paecilomyces spp., Eurotium rubrum, Mucor racemosus, Aspergillus versicolor, Penicillium commune, and P. chrysogenum). These findings illustrate the potential of porcine blood hydrolysates as a source of AMPs, particularly antifungal peptides, which are less known and less studied than the antibacterial ones. Among the tested sequences, Pep5 exhibited the most promising characteristics, including broad-spectrum activity, low MICs, and a fungicidal effect. It is, therefore, a promising candidate for further research and for potential applications in the porcine industry and beyond.

Microbial and Sensory Quality Changes in Broiler Chicken Breast Meat During Refrigerated Storage

The aim of the study was to assess the bacterial flora of broiler chicken breast meat using the MALDI method, as well as its sensory evaluation while stored refrigerated at a stable temperature (0.5 °C+/-0.5 °C). Bacterial identification based on peptidic spectra obtained by matrix-assisted laser desorption ionisation time-of-flight (MALDI-TOF MS) mass spectrometry is a rapid, inexpensive, and accurate method for identifying isolates that belong to certain bacterial phyla. The microbiological and sensory quality was assessed on the 1st and 3rd, 5th, 7th, 8th, 9th, 10th, 11th, and 12th day of refrigerated storage. The study identified psychrophilic bacteria to be the dominant microflora during the entire period of refrigerated storage. The species profile of the bacteria, however, varied in the subsequent days of storage. From the 8th day of storage, the profile was dominated by bacteria of the genus Pseudomonas. The proportionate content of Pseudomonas bacteria ranged from 89% on day 8 to 95% on day 11th of storage. The majority of the unfavourable microflora (Aeromonas species, Alcaligenes spp., Klebsiella spp., and Yersinia spp.) were observed on the 11th day of storage, which indicates that meat spoilage processes had commenced. The quality of breast meat from broiler chickens stored at 0.5 °C+/-0.5 °C was sensorially acceptable up to the 8th day of storage.

Garlic and Chitosan Improve the Microbial Quality of Hummus and Reduce Lipid Oxidation

This study investigated the antimicrobial and antioxidant effects of garlic and chitosan on hummus. Hummus was prepared by using 0.5% or 1% (w/w) chitosan, with or without 1% (w/w) garlic, and samples were stored at 4, 10, or 25 °C for 28, 21, or 7 d, respectively. The behavior of lactic acid bacteria (LAB), Pseudomonas spp., aerobic bacteria, and yeasts and molds was then investigated. Color, pH, TBARS, and rheological properties were also measured. In hummus, both with and without garlic, chitosan added at 0.5% and 1% w/w significantly (p < 0.05) decreased LAB, aerobic bacteria, yeasts, and molds, and Pseudomonas spp., at 4 °C. However, at 10 °C, adding chitosan at 1% w/w significantly reduced only aerobic bacteria (2.2 log cfu/g) and Pseudomonas spp. (1.0 log cfu/g). The pH values (regardless of treatment) decreased upon storage. The addition of garlic or chitosan did not significantly affect the lightness (L*) or yellowness (b*). However, garlic, regardless of chitosan concentration, notably reduced lipid oxidation (0.8-1.4 MDA Eq/kg of sample) and had a greater impact on the sensory properties compared to chitosan. The results of this study will encourage producers to produce hummus that has a better flavor due to garlic with enhanced microbial quality.

Unraveling the spoilage characteristics of refrigerated pork using high-throughput sequencing coupled with UHPLC-MS/MS-based non-targeted metabolomics

The spoilage of refrigerated pork involves nutrient depletion and the production of spoilage metabolites by spoilage bacteria, yet the microbe-metabolite interactions during this process remain unclear. This study employed 16S rRNA high-throughput sequencing and non-targeted metabolomics based on ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) to reveal the core microbiota and metabolite profiles of pork during refrigeration. A total of 45 potential biomarkers were screened through random forest model analysis. Metabolic pathway analysis indicated that eleven pathways, including biogenic amine metabolism, pentose metabolism, purine metabolism, pyrimidine metabolism, phospholipid metabolism, and fatty acid degradation, were potential mechanisms of pork spoilage. Correlation analysis revealed nine metabolites-histamine, tyramine, tryptamine, D-gluconic acid, UDP-d-glucose, xanthine, glutamine, phosphatidylcholine, and hexadecanoic acid-as spoilage biomarkers, with Pseudomonas, Serratia, and Photobacterium playing significant roles. This study provides new insights into the changes in microbial and metabolic characteristics during the spoilage of refrigerated pork.

A comprehensive review of intelligent packaging materials based on biopolymers: Role of anthocyanins, type and properties of materials, and their application in monitoring meat freshness

The demands of consumers for meat safety and quality have promoted the rapid development of clear, intuitive, low-cost, and real-time monitoring technologies for meat freshness. Anthocyanins-based materials can be used to monitor meat freshness by providing intuitive information of meat freshness, thus effectively avoiding the supply and consumption of spoiled meat. The complex physical and chemical changes inside the package are transformed into intuitive and recognizable color signals by anthocyanins-based materials. Therefore, this review comprehensively examined the recent advances on four materials based on anthocyanins and biopolymers including film, hydrogel, aerogel, and colorimetric sensor array for monitoring meat freshness. The etiology of meat spoilage and effects of anthocyanins addition on the performance of four materials were also investigated. Furthermore, the limitations existing in the production and application of anthocyanins-based materials are discussed and the corresponding countermeasures are proposed. The findings indicated that anthocyanins-based materials had great potential as indicative packaging of meat freshness, but their sensitivity and stability still need to be further improved. Furthermore, the combination of anthocyanins-based materials, smartphone, machine learning, computer vision, and novel chemometrics methods are crucial for the progress of anthocyanins-based materials.

Triboelectric Nanogenerator for Self-Powered Gas Sensing

With the continuous acceleration of industrialization, gas sensors are evolving to become portable, wearable and environmentally friendly. However, traditional gas sensors rely on external power supply, which severely limits their applications in various industries. As an innovative and environmentally adaptable power generation technology, triboelectric nanogenerators (TENGs) can be integrated with gas sensors to leverage the benefits of both technologies for efficient and environmentally friendly self-powered gas sensing. This paper delves into the basic principles and current research frontiers of the TENG-based self-powered gas sensor, focusing particularly on innovative applications in environmental safety monitoring, healthcare, as well as emerging fields such as food safety assurance and smart agriculture. It emphasizes the significant advantages of TENG-based self-powered gas sensor systems in promoting environmental sustainability, achieving efficient sensing at room temperature, and driving technological innovations in wearable devices. It also objectively analyzes the technical challenges, including issues related to performance enhancement, theoretical refinement, and application expansion, and provides targeted strategies and future research directions aimed at paving the way for continuous progress and widespread applications in the field of self-powered gas sensors.

Nondestructive intelligent detection of total viable count in pork based on miniaturized spectral sensor

Changes in the freshness of pork due to microbial action during complex transportation and storage indicate an urgent need for in-situ, real-time monitoring techniques for chemical spoilage of meat. This study reported the use of a portable detection device based on a miniaturized visible/near-infrared spectrometer, combined with data noise reduction and machine learning methods, to predict the total viable count (TVC) in pork samples. A rapid detection device for pork TVC was designed based on the miniaturized spectrometer; a spectral preprocessing method based on the resolution of the spectrometer was proposed; the effects of different preprocessing methods on the full-wavelength modeling effect were compared; and four different feature wavelength extraction algorithms were utilized for the feature wavelengths of pork TVC. The modeling effects of different simplified models were compared. The results showed that resolution interval correction combined with standard normal variation was the most effective in full-wavelength modeling, with correlation coefficients of prediction set (RP), root mean square errors in prediction set (RMSEP), and relative percent deviation (RPD) of 0.918, 0.464 (lg CFU/g), and 2.508, respectively; interval random frog - partial least squares regression (iRF-PLSR) had the best predictive ability among all simplified models, the number of wavelengths used in the simplified model was reduced by 85.45% compared with the full-wavelength model. In contrast, the model performance was improved with RP, RMSEP, and RPD of 0.948, 0.392 (lg CFU/g) and 2.970, respectively. The combination of a rational spectral acquisition setup and a data processing methodology, the miniaturized spectrometer showed competitive results with the complex detection system in predicting meat TVC.

Characteristics of psychrophilic bacterial communities and associated metabolism pathways in different environments by a metagenomic analysis

Psychrophilic bacteria, the dominant spoilage organisms in raw milk, secrete heat-stable extracellular proteases and lipases that lead to the decomposition of milk and dairy products. In this study, we investigated psychrophilic bacteria in 165 raw milk samples collected across four seasons and six regions in China using shotgun metagenomic sequencing and traditional culture methods. The isolated psychrophilic bacteria were classified into 40 genera and 185 species. Pseudomonas was the most prevalent, accounting for 51.13 % of the genera, while Lactococcus and Chryseobacterium were also notably abundant (> 6.0 %). Metagenomic sequencing revealed that Pseudomonas (47.9 %), Stenotrophomonas (9.75 %), Sphingomonas (6.73 %), Latilactobacillus (6.38 %) and Lactococcus (5.16 %) were the dominant genera in the raw milk samples. The diversity of psychrophilic bacteria in raw milk was strongly influenced by seasonal variations, with the sampling region being a less significant factor. KEGG annotation indicated that carbohydrate and amino acid metabolism were the primary metabolic pathways in these bacteria. Metagenomic sequencing not only accurately identifies species but also provides functional insights into psychrophilic bacteria in raw milk, aiding in understanding their activities, promoting their control on farms, and ultimately improving raw milk quality.

Biopreservation strategies using bacteriocins to control meat spoilage and foodborne outbreaks

Fresh meat is highly perishable, presenting challenges in spoilage mitigation and waste reduction globally. Despite the efforts, foodborne outbreaks from meat consumption persist. Biopreservation offers a natural solution to extend shelf life by managing microbial communities. However, challenges include the effective diffusion of bacteriocins through the meat matrix and the potential inhibition of starter cultures by bacteriocins targeting closely related lactic acid bacteria (LAB). LAB, predominant in meat, produce bacteriocins - small, stable peptides with broad antimicrobial properties effective across varying pH and temperature conditions. This review highlights the recent advances in the optimization of bacteriocin use, considering its structure and mode of action. Moreover, the strengths and weaknesses of different techniques for bacteriocin screening, including novel bioengineering methods, are described. Finally, we discuss the advantages and limitations of the modes of application of bacteriocins toward the preservation of fresh, cured, and novel meat products.

Characterization of exopolysaccharide / starch composite film incorporated with TiO2 nanoparticles and its application in chilled meat preservation

Multifunctional food packaging composite films were prepared using Pediococcus acidilactici J1 exopolysaccharide (EPS), potato starch (PS) and TiO2 nanoparticles by casting method. The microstructure, physicochemical properties and antibacterial activity of EPS/PS composite films with different weight ratio of TiO2 nanoparticles were characterized. Transmission electron microscope (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed the uniform distribution of TiO2 nanoparticles in the EPS/PS matrix. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) results indicated that the interaction between polymers and nanoparticles through non-covalent bonds. When TiO2 nanoparticles were added at 1 % (wt), the composite film had higher barrier properties against water vapor and UV-vis light, and better mechanical properties then EPS/PS film. Notably, EPS/PS/1%TiO2 composite film exhibited good antioxidant and antibacterial activity against Escherichia coli and Staphylococcus aureus. Through the analysis of the quality indexes and microbial community structure during the storage of chilled meat, the composite film slowed the oxidation rate of chilled meat and inhibited the growth of dominant spoilage bacteria, effectively extending its shelf life. All results suggested that EPS/PS/1%TiO2 composite film could serve as an effective packaging material for chilled meat, providing a novel approach to solve its limited shelf-life problem.

Linear-regression-based algorithms can succeed at identifying microbial functional groups despite the nonlinearity of ecological function

Microbial communities play key roles across diverse environments. Predicting their function and dynamics is a key goal of microbial ecology, but detailed microscopic descriptions of these systems can be prohibitively complex. One approach to deal with this complexity is to resort to coarser representations. Several approaches have sought to identify useful groupings of microbial species in a data-driven way. Of these, recent work has claimed some empirical success at de novo discovery of coarse representations predictive of a given function using methods as simple as a linear regression, against multiple groups of species or even a single such group (the ensemble quotient optimization (EQO) approach). Modeling community function as a linear combination of individual species' contributions appears simplistic. However, the task of identifying a predictive coarsening of an ecosystem is distinct from the task of predicting the function well, and it is conceivable that the former could be accomplished by a simpler methodology than the latter. Here, we use the resource competition framework to design a model where the "correct" grouping to be discovered is well-defined, and use synthetic data to evaluate and compare three regression-based methods, namely, two proposed previously and one we introduce. We find that regression-based methods can recover the groupings even when the function is manifestly nonlinear; that multi-group methods offer an advantage over a single-group EQO; and crucially, that simpler (linear) methods can outperform more complex ones.

Research progress in the use of lactic acid bacteria as natural biopreservatives against Pseudomonas spp. in meat and meat products: A review

Meat and meat products represent excellent sources of key nutrients for human health, such as protein, essential amino acids, B vitamins, and minerals. However, they are recognized as highly perishable foods since they represent an ideal substrate for the growth of spoilage and pathogenic microorganisms. Meat spoilage is a complex process that involves multiple microorganisms and a combination of intrinsic and extrinsic ecological factors. One of the most common causative agents of meat spoilage is represented by species of the genus Pseudomonas. To prevent the development of such undesired microorganisms, chemical preservatives are usually exploited by the meat industry. However, the growing consumers' concerns about potential health issues linked to the consumption of chemical preservatives has prompted the food industry to develop alternative strategies to prevent microbial spoilage in meat and meat products. Besides to the application of physical strategies, the interest towards the use of natural preservatives, such as bioprotective microorganisms (e.g., lactic acid bacteria) and their metabolites, has rapidly grown. When used in meat and meat-based products, lactic acid bacteria exhibited a bioprotective activity against spoilage and even foodborne pathogens, thanks to the production of different inhibitory compounds including organic acids, bacteriocins, carbon dioxide, hydrogen peroxide, ethanol, N-diacetyl, and lactones. This bioprotective activity might justify the use of lactic acid bacteria or their metabolites as natural preservatives to extend the shelf-life of the products. However, the effectiveness of antimicrobial activity against Pseudomonas in meat and meat products still needs to be investigated to understand the influence of the type of end product, the type of packaging, and the storage conditions (time and temperature). Moreover, the antimicrobial activity of lactic acid bacteria must also be evaluated taking into consideration their ability to maintain the sensory features of fresh meat (whether whole or minced), without negatively affecting its sourness and acidity. Of note, the results herein discussed emphasize the challenges occurred in translating in vitro findings into practical applications due to the complex interactions between bacteria, antimicrobial compounds, and food matrices.

Application of Lactiplantibacillus plantarum hydrogel coating in combination with ice temperature for the preservation of fresh yak meat

Fresh yak meat is highly nutritious and prone to spoilage, so developing suitable preservation methods is crucial. In this study, hydrogel coatings composed of konjac glucomannan, Lactiplantibacillus plantarum and gallic acid (KGX) were applied to preserve fresh yak meat under ice temperature (-1 °C). After 16 days, KGX group showed lowest total viable count (5.3 ± 0.1 log cfu/g) and total volatile basic nitrogen (13.02 ± 1.40 mg/100 g), which did not exceed the relevant standards of fresh meat. Combined assessments of color, texture, pH, drip loss rate, and thiobarbituric acid reactive substances indicated that KGX coating effectively prolonged yak meat preservation. High-throughput sequencing revealed that KGX coating effectively reduced the abundance of Pseudomonas and Candida. The application of L. plantarum hydrogel coatings in conjunction with ice temperature increased the shelf life of fresh yak meat to 16-20 days, suggesting its potential as a viable preservation method for fresh meat.

Plant-Based Ingredients Utilized as Fat Replacers and Natural Antimicrobial Agents in Beef Burgers

The present study aimed to find solutions based on the use of plant-based ingredients that would improve the nutritional quality of meat products as well as ensure sensory and microbiological quality. Two fat replacers, lemon albedo (Citrus lemon) and carob seed gum (Ceratonia siliqua), were investigated by chemical analysis and panel testing to evaluate their effect on the nutritional and sensory quality of beef burgers. The antimicrobial activity of two plant extracts, from nettle (Urtica dioica) leaves and medlar (Eriobotrya japonica) seeds, was studied, evaluating the intensity of inhibitory action and the minimum inhibitory concentration against Pseudomonas spp. and Listeria innocua strains by plate test. In addition, the antioxidant activity of both extracts was evaluated. Based on the results, lemon albedo and medlar seed extracts were validated in a food model (beef burger) by a storage test and a challenge test. The storage test results highlight that medlar seed extract prevents the formation of thiobarbituric acid reactive substances (TBARSs) and ensures microbiological quality, inhibiting Enterobacteriaceae and Pseudomonas spp. Anti-Listeria efficacy was confirmed in situ by challenge test results. In conclusion, although fat replacers ensure nutritional and sensory quality, they do not satisfy microbiological quality. This study clearly demonstrates that the safety of low-fat burgers can only be achieved through the combination of appropriate fat replacers with well-selected natural antimicrobial extracts.

Triple synergistic sterilization of Prussian blue nanoparticle-doped chitosan/gelatin packaging film for enhanced food preservation

To mitigate food spoilage caused by microbial contamination and extend the shelf life of food, antibacterial and eco-friendly biological packaging materials as an alternative to petroleum-based plastics is encouraged. Herein, an innovative and green composite film with triple antibacterial activity has been fabricated by introducing prussian blue nanoparticles (PBNPs) into chitosan (CS)-based films blended with gelatin (Gel) for the preservation of food, named CS/Gel/PB film. Due to the incorporation of PBNPs, CS/Gel/PB film exhibits enhanced mechanical, barrier and water resistance, and thermal abilities. The inherent bacterial trapping and killing capabilities of CS (contact killing), photothermal/photodynamic killing based on the excellent photothermal property of PBNPs under NIR irradiation synergistically facilitate the sterilization against Escherichia coli and Staphylococcus aureus (antibacterial ratio = 99.99 %). The film exhibits outstanding preservation capability in product storage, significantly extending the shelf life of strawberry and pork to 15 and 7 days, respectively. Meanwhile, the cytotoxicity assessment of CS/Gel/PB against HepG2 cells ascertains a cell viability exceeding 96 %, indicating a negligible toxicity level. Additionally, this film also exhibits superior biodegradability (preliminary degradation on the 10th day and completion on the 40th day) compared with PE film. Overall, these properties demonstrate great potential of CS/Gel/PB film as a novel packaging material.

Extraction of Bioactive Compounds From Centella asiatica and Enlightenment of Its Utilization Into Food Packaging: A Review

Centella asiatica is a medicinal herb, well known for its phytochemical activities because of the presence of terpenoids and polyphenols, which contribute to the bioactivity of herb extract that can be effectively utilized in the packaging industry. Biopolymers infused with C. asiatica extract could be a promising solution in the food sector. The antibacterial and antioxidant qualities of C. asiatica can help preserve the quality and lengthen the freshness of food products, thereby preventing food loss. Selection of a suitable extraction method is essential to retain the yield and properties of the bioactive compounds of C. asiatica extract. Many research has been conducted on the separation of C. asiatica by using conventional and novel extraction techniques and its execution in packaging as a functional component. This review provides an overview of the extraction of phytochemicals from C. asiatica and its utilization in biopolymer film as an active component to modify the packaging film characteristics.

The Factors Influencing the Concentration of Histamine in Jarred Baby Foods Containing Fish, Considering Evaluation of Daily Histamine Intake

Histamine is one of the biogenic amines produced naturally in the human body, but also in foods, especially those rich in protein. Exogenous and endogenous histamine is subject to degradation in vivo, but in the case of sensitive groups, including children, these degradation processes may be less intense, resulting in adverse health effects from histamine excess. The aim of the study was to determine the histamine content in jarred baby foods containing fish, taking into account the selected product characteristics and storage conditions. The study included 140 meals with added fish, intended for infants and young children, from 5 leading manufacturers available in Poland. The infant meals were analyzed on the day of opening, after 24 h and 48 h of storage in the refrigerator and at room temperature. Histamine concentration was determined by ELISA. The THQ was calculated from the EDI values for histamine. Histamine was present in all analyzed baby foods. On the day of opening, the products had a lower content of this monoamine (Me = 2.59 mg/kg), which increased systematically during storage. Samples taken at 2 °C after 48 h showed an average histamine content of 4.4 mg/kg, while products stored at 22 °C at the same time showed a 1.8-fold higher concentration of this monoamine (Me = 7.9 mg/kg). Dishes containing tuna and sea fish had higher histamine levels on average than those containing pollock. The storage conditions of the children's food had a significant effect on histamine concentration. The level of histamine in baby foods was related to the amount and type of fish in certain products. The results indicate the need for increased awareness of the risks associated with histamine, especially in a group of people with increased sensitivity to this amine, which may include infants and young children.

Psychrotrophic Bacteria Threatening the Safety of Animal-Derived Foods: Characteristics, Contamination, and Control Strategies

Animal-derived foods, such as meat and dairy products, are prone to spoilage by psychrotrophic bacteria due to their high-water activity and nutritional value. These bacteria can grow at refrigerated temperatures, posing significant concerns for food safety and quality. Psychrotrophic bacteria, including Pseudomonas, Listeria, and Yersinia, not only spoil food but can also produce heat-resistant enzymes and toxins, posing health risks. This review examines the characteristics and species composition of psychrotrophic bacteria in animal-derived foods, their impact on food spoilage and safety, and contamination patterns in various products. It explores several nonthermal techniques to combat bacterial contamination as alternatives to conventional thermal methods, which can affect food quality. This review highlights the importance of developing nonthermal technologies to control psychrotrophic bacteria that threaten the cold storage of animal-derived foods. By adopting these technologies, the food industry can better ensure the safety and quality of animal-derived foods for consumers.

Monitoring of meat quality and change-point detection by a sensor array and profiling of bacterial communities

BACKGROUND

Real-time monitoring of food consumer quality remains challenging due to diverse bio-chemical processes taking place in the food matrices, and hence it requires accurate analytical methods. Thresholds to determine spoiled food are often difficult to set. The existing analytical methods are too complicated for rapid in situ screening of foodstuff.

RESULTS

We have studied the dynamics of meat spoilage by electronic nose (e-nose) for digitizing the smell associated with volatile spoilage markers of meat, comparing the results with changes in the microbiome composition of the spoiling meat samples. We apply the time series analysis to follow dynamic changes in the gas profile extracted from the e-nose responses and to identify the change-point window of the meat state. The obtained e-nose features correlate with changes in the microbiome composition such as increase in the proportion of Brochothrix and Pseudomonas spp. and disappearance of Mycoplasma spp., and with representative gas sensors towards hydrogen, ammonia, and alcohol vapors with R2 values of 0.98, 0.93, and 0.91, respectively. Integration of e-nose and computer vision into a single analytical panel improved the meat state identification accuracy up to 0.85, allowing for more reliable meat state assessment.

SIGNIFICANCE

Accurate identification of the change-point in the meat state achieved by digitalizing volatile spoilage markers from the e-nose unit holds promises for application of smart miniaturized devices in food industry.

Development of machine learning-based shelf-life prediction models for multiple marine fish species and construction of a real-time prediction platform

At least 10 million tons of seafood products are spoiled or damaged during transportation or storage every year worldwide. Monitoring the freshness of seafood in real time has become especially important. In this study, four machine learning algorithms were used for the first time to develop a multi-objective model that can simultaneously predict the shelf-life of five marine fish species at multiple storage temperatures using 14 features such as species, temperature, total viable count, K-value, total volatile basic‑nitrogen, sensory and E-nose-GC-Ms/Ms. as inputs. Among them, the radial basis function model performed the best, and the absolute errors of all test samples were <0.5. With the optimal model as the base layer, a real-time prediction platform was developed to meet the needs of practical applications. This study successfully realized multi-objective real-time prediction with accurate prediction results, providing scientific basis and technical support for food safety and quality.

Towards Reducing Food Wastage: Analysis of Degradation Products Formed during Meat Spoilage under Different Conditions

Foodstuffs, particularly perishable ones such as meat, are frequently discarded once the best-before date has been reached, despite the possibility of their continued suitability for human consumption. The implementation of intelligent packaging has the potential to contribute to a reduction in food wastage by enabling the monitoring of meat freshness during storage time independently of the best-before date. The process of meat spoilage is associated with the formation of specific degradation products, some of which can be potentially utilized as spoilage indicators in intelligent packaging. The aim of the review is to identify degradation products whose concentration correlates with meat shelf life and to evaluate their potential use as spoilage indicators in intelligent packaging. To this end, a comprehensive literature research was conducted to identify the factors influencing meat spoilage and the eight key degradation products (carboxylic acids, biogenic amines, total volatile basic nitrogen, aldehydes, alcohols, ketones, sulfur compounds, and esters) associated with this process. These degradation products were analyzed for their correlation with meat shelf life at different temperatures, atmospheres, and meat types and for their applicability in intelligent packaging. The review provides an overview of these degradation products, comparing their potential to indicate spoilage across different meat types and storage conditions. The findings suggest that while no single degradation product universally indicates spoilage across all meat types and conditions, compounds like carboxylic acids, biogenic amines, and volatile basic nitrogen warrant further investigation. The review elucidates the intricacies inherent in identifying a singular spoilage indicator but underscores the potential of combining specific degradation products to expand the scope of applications in intelligent packaging. Further research (e.g., storage tests in which the concentrations of these substances are specifically examined or research on which indicator substance responds to these degradation products) is recommended to explore these combinations with a view to broadening their applicability.

Inter-facility characterization of bacteria in seafood processing plants: Exploring potential reservoirs of spoilage organisms and the resistome

A study was conducted in fish processing facilities to investigate the microbial composition, microbial metabolic potential, and distribution of antibiotic resistance genes. Whole metagenomic sequencing was used to analyze microbial communities from different processing rooms, operators and fish products. Taxonomic analyses identified the genera Pseudomonas and Psychrobacter as the most prevalent bacteria. A Principal Component Analysis revealed a distinct separation between fish product and environmental samples, as well as differences between fish product samples from companies processing either Gadidae or Salmonidae fish. Some particular bacterial genera and species were associated with specific processing rooms and operators. Metabolic analysis of metagenome assembled genomes demonstrated variations in microbiota metabolic profiles of microbiota across rooms and fish products. The study also examined the presence of antibiotic-resistance genes in fish processing environments, contributing to the understanding of microbial dynamics, metabolic potential, and implications for fish spoilage.

Behavior of Spoilage Bacterial Communities in Different Cuts of Enshi Black Pork under Refrigerated Storage (4 °C)

The Enshi black pig is a Chinese native breed known for its rich nutrition content and high quality, which has notable traction in the consumer market. In this study, the potential impact of the main commercial cuts from Enshi black pork carcasses (ham, loin, and belly) on the bacteria community of spoiled meat under refrigerated storage (4 °C) was assessed by using a high-throughput sequencing method. Moreover, the spoilage potential of isolated strains from spoiled pork was investigated. The results demonstrated significant differences (p < 0.05) in bacterial community diversity and composition among spoiled ham, loin, and belly samples. Linear discriminant analysis effect size (LEfSe) analysis revealed a total of 20 significantly different potential bacterial biomarkers, with the dominant genera of Pseudomonas, Psychrobacter, Shewanella and Carnobacterium. Additionally, C. divergens THT1-5, isolated from spoiled ham samples, displayed cold adaptation and higher spoilage potential in Enshi black pork. These findings are helpful for identifying key factors contributing to spoilage in Enshi black pork and developing strategies to inhibit bacterial growth during preservation.

Revolutionizing food science with mass spectrometry imaging: A comprehensive review of applications and challenges

Food science encounters increasing complexity and challenges, necessitating more efficient, accurate, and sensitive analytical techniques. Mass spectrometry imaging (MSI) emerges as a revolutionary tool, offering more molecular-level insights. This review delves into MSI's applications and challenges in food science. It introduces MSI principles and instruments such as matrix-assisted laser desorption/ionization, desorption electrospray ionization, secondary ion mass spectrometry, and laser ablation inductively coupled plasma mass spectrometry, highlighting their application in chemical composition analysis, variety identification, authenticity assessment, endogenous substance, exogenous contaminant and residue analysis, quality control, and process monitoring in food processing and food storage. Despite its potential, MSI faces hurdles such as the complexity and cost of instrumentation, complexity in sample preparation, limited analytical capabilities, and lack of standardization of MSI for food samples. While MSI has a wide range of applications in food analysis and can provide more comprehensive and accurate analytical results, challenges persist, demanding further research and solutions. The future development directions include miniaturization of imaging devices, high-resolution and high-speed MSI, multiomics and multimodal data fusion, as well as the application of data analysis and artificial intelligence. These findings and conclusions provide valuable references and insights for the field of food science and offer theoretical and methodological support for further research and practice in food science.

Potato oxidized hydroxypropyl starch/pectin-based indicator film with Clitoria ternatea anthocyanin and silver nanoparticles for monitoring chilled beef freshness

Potato oxidized hydroxypropyl starch (POHS)/pectin (P) functional and smart beef freshness indicator films were prepared using butterfly pea (Clitoria ternatea) anthocyanin (BA) and silver nanoparticles (AgNPs). BA exhibited significant pH-responsive color changes. BA and AgNPs were evenly distributed within a polymer matrix to create a compatible film with POHS/P. The films containing BA and AgNPs had good UV resistance and maintained strong mechanical strength, barrier properties, and color stability. The color of the indicator film changed from purple to green when exposed to ammonia, with the 1 % POHS/P/BA/AgNPs film showing the most sensitive response. The films also demonstrated strong antibacterial and antioxidant properties. The freshness of beef was monitored using 1 % POHS/P/BA/AgNPs films and was identified as sub-fresh and spoiled on days 4 and 7, respectively. The relationship between the color change of the indicator label and the freshness of chilled beef was established: purple for fresh meat, blue for less fresh meat, and green for spoiled meat. Thus, the new POHS/P/BA/AgNPs film can serve as a smart packaging material to indicate food freshness and extend shelf life. These results suggest that POHS/P/BA/AgNPs films have significant potential as an active and smart food packaging material.

Characterization and interactions of spoilage of Pseudomonas fragi C6 and Brochothrix thermosphacta S5 in chilled pork based on LC-MS/MS and screening of potential spoilage biomarkers

Pseudomonas and Brochothrix are the main spoilage organisms in pork, and each of these plays an essential role in the spoilage process. However, the effect of co-contamination of these two organisms in pork has not been elucidated. The changing bacterial communities during spontaneous spoilage of pork at 4 °C were evaluated using high-throughput sequencing. The dominant spoilage bacteria were isolated and these were identified as Pseudomonas fragi C6 and Brochothrix thermosphacta S5. Chilled pork was then experimentally contaminated with these strains, individually and in combination, and the progression of spoilage was assessed by analyzing various physicochemical indicators. These included total viable counts (TVC), pH, color, total volatile basic nitrogen (TVB-N), and detection of microbial metabolites. After 7 days of chilled storage, co-contaminated pork produced higher TVC and TVB-N values than mono-contaminated samples. Metabolomic analysis identified a total of 8,084 metabolites in all three groups combined. Differential metabolites were identified, which were involved in 38 metabolic pathways. Among these pathways, the biosynthesis of alkaloids derived from purine and histidine was identified as an important pathway related to spoilage. Specifically, histidine, histamine, AMP, IMP, GMP, succinic acid, and oxoglutaric acid were identified as potential spoilage biomarkers. The study showed that the combined presence of P. fragi C6 and B. thermosphacta S5 bacteria makes chilled pork more prone to spoilage, compared to their individual presence. This study provides insights that can assist in applying appropriate techniques to maintain quality and safety changes in meat during storage and further the assessment of freshness.

Research progress of chilled meat freshness detection based on nanozyme sensing systems

It is important to develop rapid, accurate, and portable technologies for detecting the freshness of chilled meat to meet the current demands of meat industry. This report introduces freshness indicators for monitoring the freshness changes of chilled meat, and systematically analyzes the current status of existing detection technologies which focus on the feasibility of using nanozyme for meat freshness sensing detection. Furthermore, it examines the limitations and foresees the future development trends of utilizing current nanozyme sensing systems in evaluating chilled meat freshness. Harmful chemicals are produced by food spoilage degradation, including biogenic amines, volatile amines, hydrogen sulfide, and xanthine, which have become new freshness indicators to evaluate the freshness of chilled meat. The recognition mechanisms are clarified based on the special chemical reaction with nanozyme or directly inducting the enzyme-like catalytic activity of nanozyme.

Noni (Morinda citrifolia) leaf extract incorporated methylcellulose active films: A sustainable strategy for browning inhibition in apple slice packaging

Methylcellulose, a prominent polysaccharide prevalent in the food sector, was considered to fabricate the active films with glutaraldehyde as a crosslinker and Noni (Morinda citrifolia) Leaf Extract (NLE) as an active agent. FTIR analysis confirms the intermolecular -OH bonding, and SEM micrograms demonstrate methylcellulose active films' homogeneous, dense morphologic appearance. Due to the crosslinking effect of glutaraldehyde and noni leaf extract, tensile strength (41.83 ± 0.134 MPa) and crystallinity (62.91 %) of methylcellulose films were improved. Methylcellulose active films suppress water and moisture uptake at various relative humidities. The inhibition capability against foodborne pathogens and the excellent antioxidant activity [DPPH (93.191 ± 1.384 %) and ABTS (90.523 ± 1.412 %)] of NLE incorporation suggested that food packed in methylcellulose active films were effective against pathogenic and oxidative attacks. During preservation, to ensure the apple slices' nutritional values, they are covered with physiochemically enhanced methylcellulose active films for up to 120 h. The minimum reduction in vitamin C, reducing sugar content, percentage weight loss, pH, and total phenolic content of apple slices preserved in MGN active films at room temperature suggests it is an affordable and efficient replacement to traditional single-use plastic packaging in the cut fruit industry.