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One of the main interests in the food industry is the preservation of food from spoilage by microorganisms or lipid oxidation. A novel alternative is the development of additives of natural origin with dual activity. In the present study, a chemically modified lysozyme (Lys) with epigallocatechin gallate (EGCG) was developed to obtain a conjugate (Lys-EGCG) with antibacterial/antioxidant activity to improve its properties and increase its application potential. The modification reaction was carried out using a free radical grafting method for the Lys modification reaction, using ascorbic acid and hydrogen peroxide as radical initiators in an aqueous medium. The synthesis of Lys-EGCG conjugate was confirmed by spectroscopic (FT-IR, 1H-RMN, and XPS) and calorimetry differential scanning (DSC) analyses. The EGCG binding to the Lys biomolecule was quantified by the Folin-Ciocalteu method; the antibacterial activity was evaluated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MCB) against Staphylococcus aureus and Pseudomonas fluorescens; the antioxidant activity was evaluated by ABTS, DPPH, and FRAP. The spectroscopic results showed that the Lys-EGCG conjugate was successfully obtained, and the DSC analysis revealed a 20 °C increase (P < 0.05) in the denaturation temperature of Lys due to EGCG modification. The EGCG concentration in Lys-EGCG was 97.97 ± 4.7 µmol of EGCG/g of sample. The antibacterial and antioxidant activity of the Lys-EGCG conjugate was higher (P < 0.05) than pure EGCG and Lys. The chemical modification of Lys with EGCG allows for the bioconjugate with a dual function (antibacterial/antioxidant), broadening the range of Lys and EGCG applications to different areas such as food, cosmetic, and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Smart films incorporated with anthocyanins as color indicators to monitor the food spoilage has attracted great attention. However, the effectiveness comparison among anthocyanin sources remains limited. Hence in this study, chitosan-based films incorporated with varying concentrations of anthocyanins sourced from either roselle or mulberry were developed. Detailed structural, morphological, physical, mechanical, and functional characteristics of these films were evaluated and compared. In general, the composite films, incorporating anthocyanins from roselle or mulberry, exhibited a deeper red–purple hue and a rougher cross-sectional appearance than the one without anthocyanins. Furthermore, while all composite films shared some representative absorption bands of FTIR spectra, there were slight variations in their area and height due to the interaction between anthocyanins and film components. Incorporating anthocyanins into chitosan-based films did not significantly affect film thickness, ranging from 74.90 to 88.35 µm. However, it notably reduced light transmittance and water vapor permeability (from 9.46 to 4.69–7.88 × 10–11 gm−1 s−1 Pa−1) while enhancing tensile strength (from 4.68 to 5.66–11.78 MPa), elongation (from 12.4 to 19.63–23.60%) and antioxidant activity (from 126.4 to 315.63–1044.54 µg Trolox equivalent/g film). Additionally, the color change patterns of chitosan-based films embedded with anthocyanins from roselle or mulberry aligned with the pH values, transitioning from red to reddish-pink (pH 3–4), pink (pH 5–6), purple (pH 7–10), and green-yellow (pH 12). During the exposure to ammonia vapor, a dark red–purple was initially observed in composite films, then faded over time, and finally shifted into light yellowish color after one hour. Both anthocyanin sources exhibited quick sensitivity to ammonia and fish spoilage. However, the color change with MARE might be more noticeable. As a result, the composite films containing anthocyanins from roselle or mulberry could be employed as intelligent films for real-time food freshness indication. [ABSTRACT FROM AUTHOR]

Herein, a novel fluorescence probe Fla-DNP based on flavonol has been designed and synthesized for rapid, specific detection of H2S. With the addition of H2S, Fla-DNP triggered thiolysis and released Fla displaying the "turn-on" fluorescence response at 566 nm, which is consistent with the reaction site predicted by calculating Electrostatic potential and ADCH charges. As an easily available H2S probe, Fla-DNP has the advantages of high selectivity, anti-interference, low detection limit (0.834 μM), short response time (6 min), and large Stokes shift (124 nm). The sensing mechanism of H2S was determined by HRMS analysis and DFT calculation. Moreover, Fla-DNP processes a wide range of multiple applications, including the detection of H2S in environmental water samples with good recovery rates ranging from 89.6% to 102.0%, as well as tracking the production of H2S during food spoilage. Meanwhile, the probe exhibits superior biocompatibility and can not only be available used for H2S detection in living cells but be further designed as an H2S-activated CO photoreleaser, based on which it can be developed as a targeted anti-cancer drug. A novel fluorescence probe Fla-DNP was synthesized utilizing 4-dimethylaminobenzoxanthone fluorescent dye (Fla) as the fluorophore, 2, 4-dinitrobenzenether group (DNP) as the recognition group, which can rapidly respond to H2S with high selectivity, anti-interference, low detection limit (0.834 μM), short response time (6 min), and large Stokes shift (124 nm) characteristics. The practical applications of Fla-DNP were further explored in water, foodstuffs samples and living cells. It is reflected that Fla-DNP can not only track H2S in complex environment water, but also can detect H2S produced during foodstuffs spoilage to monitor food freshness. More importantly, Fla-DNP can be available used for H2S detection in living cells and utilize the properties of the photoinduced release of CO from flavonols to be designed as a bifunctional platform for H2S detection and CO release. It is demonstrated that H2S-activated CO photoreleaser Fla-DNP has promise for development as an anti-cancer drug. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) blocking films are an emerging technology currently being utilized in food packaging applications. UV radiation can cause photochemical reactions in food products, resulting in color, texture, flavor, and nutritional quality degradation. These active films protect the food from photooxidation, maintain the quality attributes, and enhance the food product's shelf life. Incorporating various UV-blocking agents is the current trend in active food packaging applications. These agents absorb, reflect, or scatter the incident UV light, reducing the transmittance of UV radiation through packaging film. Here, we review the possible cause of food spoilage by photooxidation reactions. The different types of UV absorbers were used in food packaging with the benefits and effectiveness achieved. Furthermore, the mechanism and incorporation techniques of UV-shielding agents in food packaging applications have been reviewed. Finally, the challenges and future perspectives of UV-blocking films have been discussed. This article provides a comprehensive explication on the significance of utilizing UV-blocking films for food packaging applications to enhance the shelf life of food products. UV-blocking films are next-generation packaging technology enhancing the shelf life of food products. [ABSTRACT FROM AUTHOR]

A reversible optoelectronic nose is presented consisting of ten acid-base indicators incorporated into a starch-based film, covering a wide pH range. The starch substrate is odorless, biocompatible, flexible, and exhibits high tensile resistance. This optical artificial olfaction system was used to detect the early stages of food decomposition by exposing it to the volatile compounds produced during the spoialge process of three food products (beef, chicken, and pork). A smartphone was used to capture the color changes caused by intermolecular interactions between each dye and the emitted volatiles over time. Digital images were processed to generate a differential color map, which uses the observed color shifts to create a unique signature for each food product. To effectively discriminate among different samples and exposure times, we employed chemometric tools, including hierarchical cluster analysis (HCA) and principal component analysis (PCA). This approach detects food deterioration in a practical, cost-effective, and user-friendly manner, making it suitable for smart packaging. Additionally, the use of starch-based films in the food industry is preferable due to their biocompatibility and biodegradability characteristics. [ABSTRACT FROM AUTHOR]

With both foodborne illness and food spoilage detrimentally impacting human health and the economy, there is growing interest in the development of in situ sensors that offer real-time monitoring of food quality within enclosed food packages. While oligonucleotide-based fluorescent sensors have illustrated significant promise, the development of such on-food sensors requires consideration towards sensing-relevant fluorescence properties of target food products—information that has not yet been reported. To address this need, comprehensive fluorescence profiles for various contamination-prone food products are established in this study across several wavelengths and timepoints. The intensity of these food backgrounds is further contextualized to biomolecule-mediated sensing using overlaid fluorescent oligonucleotide arrays, which offer perspective towards the viability of distinct wavelengths and fluorophores for in situ food monitoring. Results show that biosensing in the Cyanine3 range is optimal for all tested foods, with the Cyanine5 range offering comparable performance with meat products specifically. Moreover, recognizing that mass fabrication of on-food sensors requires rapid and simple deposition of sensing agents onto packaging substrates, RNA-cleaving fluorescent nucleic acid probes are successfully deposited via microcontact printing for the first time. Direct incorporation onto food packaging yields cost-effective sensors with performance comparable to ones produced using conventional deposition strategies. [ABSTRACT FROM AUTHOR]

A pH-responsive and user-friendly food packaging indicator that detects ammonia was successfully developed by incorporating gelatin matrices, purple basil anthocyanins, and nano-TiO2 (1–2% by weight) into its composition. SEM images indicated TiO2, and anthocyanin were dispersed throughout the film matrix. Physical properties, mechanical properties, antimicrobial and antioxidant properties, structural and appearance properties of the films were investigated. TiO2 and purple basil extract increased the thickness, improved the mechanical and physical properties of films. Also, nanocomposite films containing TiO2, and purple basil extract showed acceptable antioxidant properties and antimicrobial effects, especially against gram-positive bacteria Staphylococcus aureus. The effectiveness of the biodegradable films in assessing the quality of fish was examined by subjecting them to storage at 4 °C for 15 days. It was observed that the packaging indicator underwent a discernible color change, transitioning from purple to green. This change occurred alongside an increase in total volatile basic nitrogen levels and a shift in pH within the packaged sample. This study suggested TiO2 can delay the occurrence of food spoilage by directly imparting the active film with good antibacterial activity; the crosslinking of TiO2 and the film matrix could improve the barrier properties of actives films. These biodegradable active films may be suitable replacements for plastic packaging materials, detect food deterioration and prolong shelf life, thereby reducing waste. [ABSTRACT FROM AUTHOR]

The object of this study was the production of a film based on gelatin and chitosan nanofiber (CNF) and containing β-cyclodextrin/Viola odorata L. (β-CD/viola) inclusion complex to monitor fish freshness and spoilage. As a result, the addition of CNF improved the surface morphology and crystalline structure of the films. The addition of the β-CD/viola complex had no adverse effect on the surface morphology and crystalline structure of the film. In addition, gelatin-based films containing β-CD/viola complex had better water vapor permeability, mechanical properties, and antioxidant activity compared to pure gelatin films. The films incorporated with β-CD/viola complex showed considerable sensitivity against pH changes and ammonia gas, and their color changed from slightly brutal pink to green by increasing pH from 2 to 12. Furthermore, the developed smart colorimetric film is used as an indicator for monitoring Kilka fish spoilage. At the end of the storage time of fish, the color of the indicator film changed from khaki to yellow-green, and its color sensitivity (SRGB) was increased to 9.93%. In conclusion, the gelatin-CNF film containing β-CD/viola complex showed a significant potential for monitoring food spoilage. [ABSTRACT FROM AUTHOR]

Most Pseudomonas spp. are responsible for spoilage in refrigerated foods such as alteration in flavor, texture and appearance. Samples of Minas Frescal cheese with blue discoloration were analysed and contained a high Pseudomonas concentration (7.72 ± 0.36 log CFU/g). Out of the 26 Pseudomonas isolates that were analyzed in our study, 19 demonstrated the capability of producing a diffusible dark pigment. Thus, a pigment-producing isolate (C020) was selected by rep-PCR fingerprinting and subsequently subjected to whole-genome sequencing. The draft genome assembled comprises 42 contigs totaling 6,366,75 bp with an average G + C content of 59.97%, and the species prediction performed by TYGS server, based on the draft genome sequence, identified the C020 as Pseudomonas carnis. In order to investigate the phylogenetic relationships of this isolate with strains already identified of this species, we performed an analysis based on whole-genomic sequences. First, an analysis of all P. carnis genomes deposited in GenBank to date shows that 11% (4/37) are misidentified, and belong to the Pseudomonas paracarnis species. A comparative analysis based on phylogenomic analysis has showed that there is no evolutionary relationship between P. carnis strains carrying second copies of trp genes related to blue discoloration (trpABCDF). This finding reinforces the assertion that these genes are contained in a mobile genetic element. However, it is worth noting that all strains carrying these secondary gene copies have exclusively been isolated from food sources. This observation provides valuable insights into the potential origins and dispersion dynamics of this genetic trait within the species. [ABSTRACT FROM AUTHOR]

Carbon dioxide is highly produced by microbial spoilage of food. Thus, the freshness of the marketed products can be represented by sensors visually highlighting the existence of CO2 within the food packages as labels. In the present work, FTIR and SEM, and XRD were used to synthesize and characterize l-lysine imprinted polymers. Then, it was utilized as a biosensor for CO2 sensing under phenyl red. By investigating its performance under CO2 gas, its applicability was proved via this synthesized biosensor for spoilage monitoring of packaged minced beef. The aerobic psychrotrophic count (PTC), aerobic plate count (APC), and Enterobacteriaceae counts were monitored to assess the samples' microbial quality in this period. The results revealed that the synthesized biosensor can act as a prevailing senor to monitor meat quality and imprint lysine on this polymer thus improving and catalyzing its reversible performance. [ABSTRACT FROM AUTHOR]

The surface of fruits is heterogenous in term of its microenvironment hence dictate the kind of microflora that develops during storage. A better understanding of spoilage organisms would lead to better preservation methods. The pomegranate was chosen, since its sturdy and spoils slow at room temperature and is ideal for studying fruit spoilage in-situ. In the current study we isolated organisms from fruit surface and study the spoilage and competition amongst microbial species. Total 17 unique bacterial isolates from pomegranate were identified. The 16S rRNA gene identification placed them in 8 major genera (Acinetobacter, Micrococcus, Pantoea, Microbacterium, Strenotrophomonas, Bacillus, Staphylococcus and Exiguobacterium). Competition assay among isolate suggested that Exiguobacterium is dominant species followed by Micrococcus, Pantoea and Bacillus. The consortium of 3 different combinations (5 bacteria each) of isolated bacteria showed the spoilage phenotype on pomegranate. Except for 3 bacterial isolates, the rest of the isolates produced any one or multiple enzymes associated with the food spoilage (cellulase, amylase, lactase, pectinase and protease). The isolates were checked for the presence of genes associated with antibiotic resistance and 78.9% of the tested micro-organisms were blaTEM positive. Aminoglycoside resistance genes were present in 10% of the tested microbes. This study demonstrated interspecies competition amongst spoilage organisms. This understanding of surface flora of fruit would give better insights to preserve fruits. [ABSTRACT FROM AUTHOR]

Zaopocu (ZPC) is a traditional fermented food from Hainan Island with tropical characteristics, and its specific fungal community may provide its distinctive acidity, taste, and flavor. Our research investigated the profiles and diversity of the fungal composition in three types of ZPC (ZPC_A, ZPC_B, and ZPC_C) using high-throughput sequencing. The results showed that the two main phyla in all samples were Ascomycota and Basidiomycota. Significant differences existed among the various samples at the genus and species levels. The primary genus in ZPC_A samples was Candida, while Kodamaea and Saccharomyces dominated ZPC_B and ZPC_C samples, respectively. Candida sorbosivorans predominated in ZPC_A, while both ZPC_B and ZPC_C samples had Kodamaea ohmeri as the dominant species. The physicochemical properties significantly impacted the composition of the ZPC fungal communities. Titratable acidity (TA) had the most pronounced impact, whereas salinity had a negligible effect. Furthermore, the correlation between physicochemical properties and representative fungal taxa showed that three core genera, Issatchenkia, Torulaspora, and Wickerhamomyces, were positively correlated with TA. The fungal communities of the three types ZPCs were primarily dominated by pathotrophs, with the guild mode of the animal pathogen having the highest content in each sample. Moreover, some species can cause food spoilage and potentially infect humans, such as Kodamaea ohmeri and Aspergillus flavus, were identified, indicating the presence of potentially pathogenic fungal contamination during the production and distribution of ZPC. Therefore, quality control should be improved. This is the first study to provide a detailed insight into the relationship between the fungal communities and physicochemical indices of traditional fermented food from the Hainan tropical region. Our findings may aid in improving the quality and safety of ZPC. [ABSTRACT FROM AUTHOR]

Increasing the shelf life of foods is of the most important interests for both industries and researchers. Application of natural, edible and environmental-friendly materials for food packaging is one of the most consensus solutions worldwide. Many bioactive compounds, such as chitosan, were suggested for this purpose. Chitosan has been incorporated with different essential oils (EOs) to improve antioxidant and antimicrobial efficiency. The chitosan combined with different EOs has been applied in various food models to increase the shelf life of foods, such as meat and meat products, fish and seafood, grains, and fruits. In addition, utilization of nano-techniques in developing chitosan-based coatings and films has provided new horizons for preserving foods and addressing waste management. These processes have been used to encapsulate EOs and increase the antioxidant and antimicrobial activity of chitosan. This paper reviews the antioxidant and antimicrobial characteristics of chitosan-based coatings and films developed by nano-techniques. Moreover, the impacts of the mentioned coatings and films on food quality and shelf life are evaluated. [ABSTRACT FROM AUTHOR]

Microbial food spoilage and foodborne disease are the main challenges in the food industry regarding food shelf life. Current preservation methods are frequently associated with changes in organoleptic characteristics and loss of nutrients. For this reason, bacteriophage offers an alternative natural method as a biocontrol agent that can reduce bacterial contamination in food without altering the organoleptic properties. This study was conducted to isolate and characterize bacteriophage from soil to control food spoilage bacteria, such as Bacillus cereus and Bacillus subtilis, and foodborne pathogenic bacteria, such as enterotoxigenic Escherichia coli (ETEC) and enterohemorrhagic E. coli (EHEC). Isolation was done by agar overlay assay method, and phages BC-S1, BS-S2, ETEC-S3, and EHEC-S4 were recovered. The host range of all isolated phages tended to be narrow and had high specificity towards the specific bacteria. The phage efficiency were measured where ETEC-S3 showed no effectivity against B. cereus and EHEC-S4 showed low efficiency against Enteropathogenic E. coli (EPEC). Morphology analysis was conducted for phage BC-S1 and ETEC-S3 with Transmission Electron Microscopy (TEM), and it is shown to belong to the Caudovirales order. Phages BC-S1 and BS-S2 significantly reduced the host bacteria when applied to the cooked rice and pasteurized milk samples with miMOI of 0.1. While phage ETEC-S3 at miMOI of 0.001 and phage EHEC-S4 at miMOI of 1 also showed a significant reduction when applied to chicken meat and lettuce samples at storage temperatures of 4 °C and 28 °C. The highest bacterial reduction of 100% was shown by phage BC-S1 on pasteurized milk samples and reduction up to 96.06% by phage ETEC-S3 on chicken meat samples at 28 °C incubation. [ABSTRACT FROM AUTHOR]

The detection of biogenic amines released from degraded meats is an effective method for evaluating meat freshness. However, existing traditional methods like titration are deemed tedious, while the use of sophisticated analytical instruments is not amenable to field testing. Herein, a cyanostilbene-based fluorescent array was rapidly fabricated using macroarray synthesis on a cellulose paper surface to detect amines liberated from spoiled beef, fish, and chicken. The fluorescence changes of immobilized molecules from the interaction with gaseous amines were used to monitor changes in freshness levels. Thanks to the high-throughput nature of macroarray synthesis, a set of highly responsive molecules such as pyridinium and dicyanovinyl moieties were quickly revealed. Importantly, this method offers flexibility in sensing applications including (1) sensing by individual sensor molecules, where the fluorescence response correlated well with established titration methods, and (2) collective sensing whereby chemometric analysis was used to provide a cutoff of freshness with 73–100% accuracy depending on meat types. Overall, this study paves the way for a robust and cost-effective tool for monitoring meat freshness. [ABSTRACT FROM AUTHOR]

A new approach is introduced for rapid and reliable bacteria detection in food. Namely, static headspace-comprehensive two-dimensional gas chromatography (HS-GC × GC) with backflushing. The introduced approach provides fast detection of Escherichia coli (E. coli) in enriched ultra-high-temperature processed (UHT) dairy milk. The presence of E. coli may be indicated by detecting microbial volatile organic compounds emanating from test solutions inoculated with E. coli. In the present investigation, HS-GC × GC analysis is preceded by conventional enrichment in nutrient broth and inoculated samples are clearly discernable from controls following as little as 15 h sample enrichment. Headspace equilibration for 28 min followed by an 8 min GC × GC analysis of enriched test solutions reduces time-to-response by approximately one full day compared to conventional culture-based methods. The presence of ethanol, 1-propanol, and acetaldehyde may be used as a putative marker of E. coli contamination in milk and the introduced approach is able to detect single-cell initial bacterial load. Faster, reliable detection of pathogens and/or spoilage microbes in food products is desirable for the food industry. The described approach has great potential to complement the conventional workflow and be utilised for rapid microbial screening of foodstuff. [ABSTRACT FROM AUTHOR]

Background: Guava (Psidium guajava Linn.) has been traditionally used in the treatment of a wide range of diseases due to its rich content of secondary metabolites. Aim: This study was aimed to evaluate the effect of altitude and solvent systems on guava leaves crude extract's phenolics and flavonoid content, antioxidant, antimicrobial, and toxicity nature. Methods: Guava leaves were collected from three different geographical locations in Nepal while solvents with an increasing polarity index were used for extraction. The yield percentage of extracts was calculated. Total Phenolic Content, Total Flavonoid Content, and antioxidant activity were determined by the Folin-Ciocalteu method, Aluminium chloride colorimetric method, and DPPH (2,2′-Diphenyl-1-picrylhydrazyl) assay respectively. The quantification of fisetin and quercetin was performed using the HPLC with method validation. The antimicrobial activity of the extracts was tested against bacteria and fungus isolated from spoiled fruits and vegetables and identified through 16s and 18s rRNA sequencing. Finally, Brine Shrimp Lethality Assay (BSLA) was used for testing the toxicity of the extracts. Results: The phenolic and total flavonoid content was found to be higher in ethanol extract (331.84 mg GAE/g dry extract) and methanol extract (95.53 mg QE/g dry extract) from Kuleshwor respectively. Water extract of guava leaves from Kuleshwor (WGK) did not show significantly different antioxidant activity when compared to methanol and ethanol extracts. Fisetin and quercetin were higher in WGK (1.176 mg/100 g) and (10.967 mg/100 g) dry extract weight respectively. Antibacterial activity against food spoilage bacteria was dose-dependent and found to be highest for all the extracts from different solvents and altitudes at higher concentrations (80 mg/ml). Similarly, methanol and ethanol guava extracts from all locations showed antifungal activity against Geotrichum candidum RIBB-SCM43 and Geotrichum candidum RIBB-SCM44. WGK was found to be non-toxic. Conclusion: Our study concludes that the antioxidant and antimicrobial activity of WGK was found to be similar statistically to that of methanol and ethanol extracts of Bishnupur Katti and Mahajidiya. These results suggest the possibility of using water as a sustainable solvent to extract natural antioxidant and antimicrobial compounds which can further be used as natural preservatives to extend the shelf life of fruits and vegetables. [ABSTRACT FROM AUTHOR]

The increase in rate of global population growth demands for the variety of nutritionally rich and functionally important food options. The elevated rate of foodborne illnesses comes along as a challenge to accomplish the goal of efficiently producing enough food. In order to deal with this problem, this research focused on analysing the antimicrobial property of a highly significant food plant i.e., Aloe vera (Barbadensismiller) against the commonly responsible microbes for food spoilage; namely Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Pseudomonas. A hybrid mode study was performed using disc diffusion technique for in vitro analysis of the anti-microbial activity of bitter, non-bitter and microencapsulated form of Aloe-vera. Additionally, a molecular docking study was performed for in-silico validation of the antimicrobial potential of the 12 bioactive compounds of Aloe vera against these pathogens. The results of this hybrid study indicated the inhibitory effect of Aloe vera against these foodborne pathogens. [ABSTRACT FROM AUTHOR]

This research has evaluated the effects of different levels (0.5, 1, and 1.5%) of grape seed oil (GSO) on the various aspects of gelatin/guar gum (GG) based biodegradable films. Bovine gelatin and GG-based biodegradable films incorporated with cold press GSO were prepared through the casting technique. With the increase of GSO concentration tensile strength (TS) (8.32–6.54 MPa), water vapor permeability (4.80–2.65 × 10–10 g mm/m2 h Pa), moisture content (MC) (17.52–15.01%), and solubility in water (36.52–27.25%) decreased significantly (p < 0.05). Structural (SEM, XRD), chemical (FTIR), thermal (DSC), antibacterial properties, and color parameters of films were also investigated. SEM images proved a uniform structure in the gelatin/GG film surface. The incorporation of GSO into the films led to the formation of a slightly porous structure. Total color difference (ΔE) also increased with the level of incorporated GSO (p < 0.05). XRD analysis of films demonstrated a typical semi-crystalline structure. When GSO was incorporated into the film matrix the melting point (Tmax) increased. The gelatin/GG/GSO films showed improved antimicrobial activity against tested both Gram-negative and Gram-positive bacteria. The biological properties of gelatin/GG/GSO films make them a promising material to prevent food spoilage for use in food packaging. [ABSTRACT FROM AUTHOR]

Temperature sensitive foods require monitoring of their time–temperature history in order to assure their safety and high quality. The same holds for other perishable products such as medical and pharmaceutical. The best means to have information on the time–temperature history of a product is by having measurement of these variables along the whole product shelf-life. As an answer to this need several time–temperature indicators have been developed and commercialized for monitoring the quality of food products. In this work a full history time–temperature indicator (TTI) has been designed and developed based on capillary penetration of safe and low surface tension liquids in micro porous polyethylene porous media. For the development of the indicator the appropriate porous media and penetration liquids were selected and capillary penetration of the selected liquids took place at two different temperatures. Based on the results of the capillary penetration experiments the TTI was developed and a prototype was evaluated in a food product in order to assess its capability to be used in food packaging. The results showed that the TTI is simple in use and could provide a quantitative and easy-to-read response. Moreover, the response of the TTI could be calibrated by changing several design parameters, in order to match the quality deterioration kinetics of the specific food product to be monitored. [ABSTRACT FROM AUTHOR]

Colorimetric food freshness indicators (CFFIs) are important in food packaging for monitoring the quality of food products during storage and transportation. CFFIs can supplement the conventional "best before date" embedded in food product packages by providing real-time and naked-eye quality information to the stakeholders, thereby ensuring product safety and preventing food waste. Various cellulosic materials have been employed as the matrix/carrier in CFFIs. In addition to their transparency, nontoxicity, high water/dye absorption capacity, unique film-forming property, three-dimensional network formability, superior mechanical properties, easy processability, and widespread availability, cellulosic materials have various functional groups acting as ideal sites for the immobilization of the indicator dye, which play a crucial role in the efficiency of CFFIs. Furthermore, anionic cellulose-derived polymers can act as an electrostatic binding site for positively charged freshness biomarkers, such as total volatile basic nitrogen compounds. This review covers the most-significant peer-reviewed papers on cellulosic material-based CFFIs for meat, fruits, and milk to understand the current research trends and recently developed cellulosic material-based CFFIs. The challenges related to cellulosic material-based CFFIs are presented, including their efficiency and selectivity to other biomarkers and the safety concerns related to certain ingredients, including indicator dyes, crosslinkers, and plasticizers, employed in their fabrication. Solution casting is the most widely used laboratory method for the preparation of cellulosic material-based CFFIs. However, solution casting is not viable for mass production owing to its long drying time. The thickness, dimension, and location of CFFIs inside the food package (their distance from the analytes) affect their colorimetric response. Thus, industrially viable methodologies, such as contact-type CFFIs using innocuous materials such as cellulose and its derivatives doped with food-grade indicator dyes, must be developed. This review shows that cellulosic material-based CFFIs doped with bio-based natural indicator dyes such as anthocyanins (ACNs) offer viable options for intelligent food packaging. Different approaches for improving the sensitivity and reactivity of ACNs are also addressed. Owing to their viability and potential, cellulosic material-based CFFIs will continue to remain an important research topic in the future. [ABSTRACT FROM AUTHOR]

Consumers in many countries express increased expectations associated with food quality. When their satisfaction is not achieved, they may raise a complaint. The main aim of this study was to analyze the overall perception of food quality and complaints associated with poor food quality. In parallel, this study categorized food quality and complaint attributes based on a Kano model. Finally, this research also examined food properties that are key contributors to consumer complaints as well as complaint resolution actions in handling complaints. To perform this research, a field survey was conducted with 844 interviewees from the Republic of Serbia. Food products perceived to be of the highest quality were spices, cereals, and confectioneries, opposed to meat and ready-to-eat meals scoring lowest. Food odor is recognized as a perfect dissatisfaction attribute (associated with food spoilage). A cluster analysis revealed two clusters dependent on age and education of the respondents. The 'demanding consumers' are not satisfied with taste, odor, color, and physical appearance of purchased food, opposed to the 'tolerant consumers' with no quality issues. The majority of respondents expects some compensation in case of complaints associated with poor quality but didn't raise any oral or written complaints lately. In case of complaints, a perfect resolution action is product replacement. This survey revealed that taste and odor are highly ranked reasons for complaints, that the younger population is more tolerant to low quality and that the type of food is in correlation with complaints and perception of food quality. [ABSTRACT FROM AUTHOR]

The bacterial genus Enterococcus encompasses 38 species. Two of the most common species are E. faecalis and E. faecium. Recently, however, there has been an increase in clinical reports concerning less prevalent Enterococcus species, such as E. durans, E. hirae, and E. gallinarum. Rapid and accurate laboratory methods are needed to facilitate the identification of all these bacterial species. In the present study, we compared the relative accuracy of matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS), VITEK 2, and 16S rRNA gene sequencing using 39 enterococci isolates from dairy samples, and compared the resultant phylogenetic trees. We found that MALDI-TOF MS correctly identified all isolates at the species level except for one, whereas the VITEK 2 system, which is an automated identification system using biochemical characteristics of species, misidentified ten isolates. However, phylogenetic trees constructed from both methods showed all isolates in similar positions. Our results clearly showed that MALDI-TOF MS is a reliable and rapid tool for identifying Enterococcus species with greater discriminatory power than the biochemical assay method of VITEK 2. Key Points: Although certain Enterococcus genus are used as starter cultures in many food products, this bacterial group is considered a human and animal pathogen which can cause nosocomical infections and urinary tract infections, and contribute to food spoilage. Accurate and reliable identification of Enterococcus genus present in food is of great importance for predicting shelf life and for managing and reducing microbiological food hazar. Phylogenetic trees obtained from MALDI-TOF MS and VITEK2 analyses were compared to evaluate the discriminative resolution of these two systems. [ABSTRACT FROM AUTHOR]

Multifunctional active and innovative biopolymer-based indicator films consisting of a blend of gelatin (GEL) and basil seed gum (BSG) with different concentrations of saffron petal extract (SPE) were prepared. The a* and b* color values depended on pH, which highlighted that the SPE could be used as a pH indicator. The results showed the anthocyanin content increased water vapor permeability (WVP), elongation at break (EAB), and thickness up to 5.02 g/s m Pa×10− 10, 111.21%, 102.71 μm, respectively, of the GEL-BSG indicator films. As expected, the SPE concentration from 0 to 20% (v/v) decreased tensile strength (TS), moisture content, water solubility and transparency to 5.54 MPa, 16.47%, 30.05%, 56.37%, respectively. The surface and cross-sectional microstructures of the indicator films were examined using scanning electron microscopy, while film component interactions were evaluated using Fourier transform infrared spectroscopy. The incorporation of SPE significantly increased the antibacterial and antioxidant activity of the GEL-BSG indicator films compared to the control film, mainly attributed to an increase in the total phenolic content. In their application experiment, the GEL-BSG indicator film was used as a label to monitor the freshness of fish maintained at 4 °C, and the results showed that the film's color changed from red to yellow when the fish deteriorated. Our results suggest that SPE-loaded biopolymer films could be used to monitor and prevent food spoilage simultaneously. [ABSTRACT FROM AUTHOR]

The use of jackfruit peel as a source for natural and fully biodegradable "nanocellulose" (NC) for the production of bioplastics with Azadirachta indica (A. indica) extracts and polyethylene glycol (PEG) for the antibacterial properties is investigated. The characterization of the biocomposite using FT-IR and WXRD was reported. The physicochemical properties including thickness, moisture content, water holding capacity, swelling, porosity, and biodegradability in soil were investigated. The incorporation of A. indica extract revealed an increased shelf life due to the strong antibacterial activity, and these biocomposites were degraded in soil within 60 days after the end use without any harm to the environment. Jackfruit-derived nanocellulose film blended with A. indica extract exhibited strong antibacterial activity against gram-positive and gram-negative food spoilage bacteria. Disc diffusion assay, live/dead assay, and CFU analysis confirmed the antibacterial property of the synthesized film. Moreover, the films clearly prevented the biofilm formation in bacteria. Thus, the developed bioplastics can be utilized as appropriate substitutes to food packaging materials and also for biomedical applications such as wound dressings. [ABSTRACT FROM AUTHOR]

Polypyrrole (PPy) and metallic silver (Ag) particles were used as a new combination for food packaging applications. Due to numerous interesting properties offered by such materials, their use as a direct contact product in the food industry is of great interest. PPy was coated on cellulosic paper, previously extracted from carton packages of food and beverages, by an in situ chemical oxidative polymerization in the presence of two different oxidizing agents, namely iron chloride and silver nitrate. The first one, well known as a typical oxidant, led to PPy coating-doped chloride ions (PPy–Cl), while the second gives, after an electronic transfer between the monomer and silver cation, a composite containing polymer and metallic silver particles (PPy–Ag). The modification of the cellulosic paper was confirmed by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectroscopies and scanning electron microscopy (SEM). On the other hand, the prepared materials were tested as antibacterial agents as well as sensors for toxic volatile organic compounds generally produced during food spoilage. The presence of metallic silver particles increases the antibacterial activity of our formulation compared to the system without silver. Furthermore, the significant change in the internal resistance of PPy–Ag composite when exposed to ammonia, acetone, methanol and ethanol vapors proved its high sensing properties. [ABSTRACT FROM AUTHOR]

A photo-induced metal–organic framework-enzyme hybrid nanosystem was developed via a controllable physical embedding method that displays dual enzymatic and photo-non-enzymatic strategy which cause high stability and cascade catalytic performance to oxidation of o-phenylenediamine and generate a UV–Vis signal at 450 nm for the tracing and sensitive detection of putrescine (Put). Under optimal conditions, the present bioassay provides a wide detection range from 0.02 to 10 µM and 20–80 µM with a detection limit of 5.5 nM, which is more desirable than numerous previous reports. In addition, the established colorimetric photo-bioassay can selectively and accurately identify Put in the presence of other distributing species. The present work provides an elegant strategy to merged photo-nanozymes' and enzyme capabilities and also broadened the sensing strategies of photo-nanozymes with promising potential in the realm of cancer diagnosis and food quality monitoring as well as its potential in various bioassays and heterogeneous catalysis fields. [ABSTRACT FROM AUTHOR]

The object of the present study was to develop polycaprolactone (PCL)/casein (Cas) electrospun nanofibers incorporated with green tea essential oils (GTO) as an active food packaging to prevent spoilage and food loss. The obtained results show that increase in the weight concentration of Cas leads to increasing the viscosity and diameter of nanofibers up to the range of 237–298 nm, leading to enhance the mechanical strength owing to the creation of hydrogen bonds and increased surface wettability. However, increase of the PCL content led to the reduction of the fiber diameter (203 ± 108 nm), more porosity (around 80%), and high thermal stability. In addition, the nanofiber samples, with 5% (PC5), and 12% (PC6) concentrations of GTO exhibited a long-term sustained release with high antioxidant activity 39.85% and 58.56% for PC5 and PC6, respectively. These findings suggested the promising applications of the produced PCL/Cas/GTO electrospun fibers for active food packaging. [ABSTRACT FROM AUTHOR]

Novel pH-colorimetric intelligent films were designed from agar and methylcellulose matrix (AM) with soybean wax (SBW) in several percentages (5, 10, 15, and 20%w/w) combined with purple cauliflower (CF) anthocyanins as an indicator of the shrimp freshness at 4 °C and 25 °C of storage temperatures. The color was observed in a mixture of AM/CF anthocyanins with SBW (hydrophobic), which completely converted in pH acidity 2–6 and somewhat in pH alkalinity 7–12, equivalent to the color seen when exposed to ammonia vapors 100 mmol/L. The spectroscopic analysis indicated that SBW was successfully settled into the AM/CF film. The homogenized SBW films enhanced the mechanical, thermal, antioxidant, control release of the anthocyanins and physical properties, significantly reducing water vapor permeability in AM/CF/15%SBW. Remarkably, SBW films showed total protection for UV–Vis light and a beneficial decline in visible light. Lastly, pH-colorimetric film validity to indicate the freshness/spoilage of a model food (shrimp) was confirmed. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the antioxidant properties and total phenolic content of a dairy product (yogurt) supplemented with Thymus willdenowii (synonym: Thymus hirtus) essential oil. The evaluation of the antioxidant and antibacterial activities of the oil against food spoilage bacteria and lactic acid strains was also assessed. The chemical composition of the oil was obtained by GC/MS. The evaluation of the antioxidant activity of a fortified yogurt with this oil was assessed by Oxygen radical absorbance capacity test (ORAC). The main component of the oil was Linalool (89.55%). DPPH, and Ferric reducing power revealed a weak antioxidant activity (IC50 > 1600 µg/mL, > 800 µg/mL respectively) while a moderate activity was obtained with ABTS and CUPRAC tests (38.06 ± 0.30, 56.15 ± 1.07 µg/mL respectively). A high concentration of the oil is needed to delay the inhibition of the β-carotene (> 800 µg/mL). Thus, a strong antibacterial activity was observed against the pathogenic strains with the high inhibition diameter for B.cereus ATCC10876 (31.75 ± 1.50 mm) while a weak effect was observed against lactic acid bacteria. A significant decrease in the antioxidant potential of non-supplemented yogurt was observed from day 1 to 21 while there was no significant difference in ORAC of supplemented yogurt with the oil. The maximum of total phenolic content was observed in day 21 of cold storage (252.92 ± 3.01 µg GAE/mL of yogurt). The essential oil studied could be an effective natural additive to yogurt avoiding the use of synthetic preservatives. [ABSTRACT FROM AUTHOR]

Development of materials with green and efficient for restraining the growth of the harmful microorganisms is vital for food safety. Herein, we constructed nanoliposomes with cinnamaldehyde (CIN), an active component of natural cinnamon essential oil, for the long-term inhibition of microbes in food spoilage. In this strategy, cinnamaldehyde nanoliposomes (CIN-NLs) were prepared by the method of thin film dispersion, and then decorated with ε-polylysine (ε-PL) to obtain ε-polylysine/cinnamaldehyde nanoliposomes (ε-PL/CIN-NLs). Results identified that CIN-NLs and ε-PL/CIN-NLs were in spherical and nanoscale, and the nanoliposomes had larger particle size distribution (122.5 ± 3.51–680.4 ± 7.40 nm) and higher encapsulation efficiency (19.4 ± 0.3–30.4 ± 0.2%) after ε-PL (2 mg/mL) decoration. When the CIN concentration was 4 mg/mL, the highest encapsulation efficiency was acquired as 30.4 ± 0.2% by ε-PL/CIN-NLs. CIN-NLs and ε-PL/CIN-NLs showed great activity on inhibiting the growth of Aspergillus flavus and Penicillium citreo-viride, and the inhibition zone diameter of ε-PL/CIN-NLs (26 ± 1.1 mm and 45 ± 1.7 mm, respectively) was significantly larger than that of CIN-NLs (20 ± 1.5 mm and 35 ± 2.1 mm, respectively) in final growth of two fungi. The studies indicated that that ε-PL decoration effectively improved the long-term antifungal activity characteristics of CIN nanoliposomes. Findings from current study can provide a new method to prevent food spoilage and direct future development of green antifungal packing for use in food preservation. The schematic representation of ε-PL/CIN-NLs and the colony growth images of Aspergillus niger and Penicillium citreo-viride. [ABSTRACT FROM AUTHOR]

Chickpeas and lentils contain prebiotic carbohydrates, including galacto-oligosaccharides (GOS), that confer health benefits but can also lead to undesirable effects like bloating and flatulence. Legume processing reduces these disadvantages and usually consists of the soaking and cooking of the legume seeds. In their industrial production, the processing water is considered waste. As different carbohydrates have recognized stabilization properties on lactic acid bacteria during dehydration processes, this study aimed to investigate the protective effect of GOS-containing wastewater extracts from cooking chickpeas and lentils, as well as fructo-oligosaccharides, and sucrose (used for comparative purposes), on the stability of freeze-dried Lactiplantibacillus plantarum WCFS1, by measuring biological (culturability, storage stability, acidifying activity), chemical (pH), and physical (water content) properties. The best storage stability was observed for mixtures with GOS-containing wastewater legume extracts. Protection of lactic acid bacteria strains with GOS-containing wastewater legume extracts would limit their spoilage in food production, positively impacting the environment. [ABSTRACT FROM AUTHOR]

Biogenic amines, produced by bacterial enzymatic reactions in food storage or processing, serve as indicators in food processing industries to assess food quality and freshness. Biogenic amines also often associated with various health problems, including abnormal immune responses and gastrointestinal disease. Previously, salphen base complexes have been reported but still exhibited low fluorescence enhancement upon biogenic amines. This research focused on synthesizing and characterizing new Zn(II) Schiff base complex with indole sidechain to enhance the fluorescence property and exploring their binding behaviour with the biogenic amines, which were phenylethylamine and cadaverine. The Zn(II) indole Schiff base complex’s structure was verified by diverse spectroscopic techniques. Then, the binding behaviours between the Zn(II) indole Schiff base complex with the biogenic amines were analyzed using UV-Vis, fluorescence spectroscopy, and Job’s plot analysis. UV-Vis binding study results indicated that the synthesized complexes could bind stronger with phenylethylamine than cadaverine, with binding constant, Kb= (8.21 ± 0.58) × 104 M− 1 and (2.506 ± 0.004) × 104 M− 1 respectively. Moreover, Zn(II) indole Schiff base complex-phenylethylamine binding also generated higher fluorescence enhancement than cadaverine, which were 54% and 51% respectively. Based on Job’s plot analysis, the complex and biogenic amines were bound in the ratio of 1:1. To conclude, the synthesized complex has promising potential as a sensing material for biogenic amines detection in food. The complex is recommended to be deployed in the development of solid-state fluorescence sensor for biogenic amines detection for monitoring the food spoilage in the food industry in the future. [ABSTRACT FROM AUTHOR]

Technologies for rapid identification and prediction of food spoilage can be crucial in minimizing food waste and losses, although their efficiency requires further improvement. This study aimed to pinpoint specific near-infrared (NIR) wavelengths that could indicate spoilage in raw chicken breast fillets. In this study, commercial tray-packs of boneless, skinless chicken breast fillets stored in a walk-in cooler at 4 °C were periodically tested every other day until they reached the spoilage state (identified by > 7 log CFU/ml). A portable Hyper spectral spectroscopy device (Field Spec Hi-Res4), with a range of wavelengths of 350–2500 nm, was used to measure reflectance. In addition to hyper-spectral analysis, aerobic plate counts were conducted on the fillets. The data from these counts were then used to train a Back Propagation Neural Network (B.P.N.N.) with specific parameters (250,000 steps, a learning rate of 0.02, and 5 hidden layers) and Linear-Support Vector machines (SVM-Linear) with ten-fold cross-validation technique to categorize spoilage into three stages: baseline microbial count (up to 3 log CFU/ml) (Initiation), propagation (between 3 and 6.9 log CFU/ml), and spoiled (> 7 log CFU/ml). The feature extraction process successfully identified the most representative signature wavelengths of 385 nm, 400 nm, 432 nm, 1141 nm, 1321 nm, 1374 nm, 2241 nm, 2292 nm, 2311 nm, and 2412 nm from the whole hyper-spectral profile, which facilitated the classification of different phases of spoilage. The BPNN model demonstrated a high classification accuracy, with 93.7% for baseline counts, 95.2% for the propagation phase, and 98% for the spoiled category. These signature hyperspectral wavelengths hold the potential for developing cost-effective and rapid food spoilage detection systems, particularly for perishable items. [ABSTRACT FROM AUTHOR]

In recent years, there is a rapid advancement in the reinforcement of polymers using graphene-based materials (GBMs) such as graphene (thickness = ~ 0.34 nm), graphene oxide (GO, thickness = ~ 1.1 nm), and reduced graphene oxide (rGO). GBMs and their nanocomposites have been widely applied in numerous industries. Due to their remarkable properties, GBMs have also been incorporated in food packaging materials, providing efficient reinforcement in mechanical strength, barriers to light, water vapour, and gases, as well as antimicrobial and antioxidant properties, which are crucial in preventing food spoilage. This review aims to assess and summarize the published data in the use of GBMs in polymeric composites, particularly for food packaging. Then, we highlight the main factors that influence the behaviour and properties of the GBMs during the fabrication of the composites. Lastly, this review provides a brief summary of the current limitations as well as the food safety concerns regarding GBMs in food packaging. [ABSTRACT FROM AUTHOR]

Viscosity is one of the most important physical parameter toward liquid. Monitoring of the viscosity variations during the food spoilage process is of great importance for metamorphic extent determination, since food deterioration may cause serious foodborne illnesses. The method with rapid detection, high sensitivity, cheap equipment, and fast results output is obliged to be exploited. Therefore, one kind of viscosity-sensitive molecular rotor (DPTPM) with large Stokes shift (184 nm), and long emission wavelength (688 nm) has been developed. And the rotor has good photostability, selectivity, universality in various commercial beverages. With the aid of DPTPM, the thickening effects of food thickeners can be captured. In addition, the viscosity levels in the beverages at different metamorphic stages were determined, and revealed that the microenvironment viscosity level is highly dependent on the liquid food metamorphic period. It is noting that this approach can facilitate the continued perfection of fluorescent analytical methods toward food quality and safety inspection. [ABSTRACT FROM AUTHOR]

Lentinus crinitus basidiocarps are an alternative to antimicrobials, but the stipe (24% basidiocarp) is discarded even with potential antimicrobial activity. This study evaluated the antimicrobial activity of L. crinitus basidiocarp pileus and stipe extracts against foodborne pathogens and food spoilage microorganisms. Basidiocarps of L. crinitus were grown in sugarcane bagasse and rice husks and the pileus and stipe methanolic extract was analyzed by broth microdilution method for antimicrobial activity against eight bacteria and eight fungi. The minimum bactericidal concentration values for pileus and stipe ranged from 0.40 to 0.50 mg mL− 1, for streptomycin from 0.10 to 0.50 mg mL− 1, and for ampicillin from 0.40 to 1.20 mg mL− 1. The minimum fungicidal concentration values for pileus and stipe ranged from 0.06 to 0.60 mg mL− 1, for bifonazole from 0.20 to 0.25 mg mL− 1, and for ketoconazole from 0.30 to 3.50 mg mL− 1. Extracts had bacteriostatic, bactericidal, fungistatic and fungicidal activity against all microorganisms, but with greater efficiency and specificity for some microorganisms. Both pileus and stipe are promising and sustainable alternatives for use in food, agricultural, and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

A novel nanoassembly was constructed through encapsulating upconversion nanoparticles (UCNPs) into a metal–organic framework structure (ZIF-8), in which doxorubicin (DOX) was absorbed into pores of ZIF-8. The blue emission of UCNPs was quenched by DOX through the fluorescence resonance energy transfer (FRET) strategy. When the nanoprobe was exposed to food samples with different pH values, ZIF-8 collapsed to release DOX molecules, resulting in upconversion recovery. The porous structure of ZIF-8 provides abundant space for DOX absorption, which significantly improves the detection capacities and accuracy. It is shown that the probe has a good linear relationship when pH values vary from 2.5 to 7.4, and can distinguish pH variations as low as 0.5 in real samples. This strategy has been successfully used to determine food spoilage by determination of pH variations. [ABSTRACT FROM AUTHOR]

Consumers demand clean-label food products, necessitating the search for new, natural antimicrobials to meet this demand while ensuring food safety. This review aimed at investigating the antimicrobial properties of black pepper (Piper guineense) against foodborne microorganisms. The existence of foodborne illness, food spoilage, food waste, the resulting negative economic impact of these issues, and consumer interests have all pushed the food industry to find alternative, safe, and natural antimicrobials to be used in foods and beverages. Consumers have also influenced the demand for novel antimicrobials due to the perceived association of current synthetic preservatives with diseases and adverse effects on children. They also have a desire for clean-label products. These combined concerns have prompted researchers at investigating plant extracts as potential sources for antimicrobials. Plants possess many antimicrobial properties; therefore, evaluating these plant extracts as a natural source of antimicrobials can lead to a preventative control method in reducing foodborne illness and food spoilage, inclusively meeting consumer needs. In most regions, P. guineense is commonly utilized due to its potent and effective medicinal properties against foodborne microorganisms. [ABSTRACT FROM AUTHOR]

Food preservatives especially used to prevent microbiological spoilage in nutritional products are among the most indispensable additives. Here, the biochemical effects of three commonly used preservatives, sodium benzoate (SB), potassium sorbate (PS) and sodium nitrite (SN), on Saccharomyces cerevisiae were investigated. 5–100 mM SB, 300 ppm PS and 25–100 mM SN significantly inhibited early exponential yeast cell proliferation compared to the control after 12 h exposure. Cell metabolic activity percentages were also significantly inhibited at the studied highest three concentrations. While glutathione S-transferase activity generally increased after SB and PS treatments, superoxide dismutase activity increased only after 50 mM SB treatment. Although the lipid peroxidation marker malondialdehyde levels generally increased as a result of treatments with food additives, significant increases were determined in 300 ppm PS, and 50 and 100 mM SN groups. According to the principal component and hierarchical cluster analysis, food additive treated groups clearly discriminated from control. Finally, the principal component analysis (PCA) loading plots showed that higher doses of food additives altered lipid concentration, disrupted proteins and increased the concentrations of mannans and β-glucans. These findings are significant in terms of better understanding the underlying mechanism of food additive induced toxicity for the control of yeast cell proliferation. [ABSTRACT FROM AUTHOR]

In this study, a simple pH-colorimetric film was developed to detect the spoilage of pasteurized milk. The biosensor was fabricated by incorporating the pH-sensitive anthocyanins (AC) extracted from blue pea (Clitoria ternatea L.) flower into a starch-based edible film. The color responses of both AC aqueous extracts and edible films incorporated with different AC concentrations towards different pH buffers (pH 2–11) were measured using Ultraviolet–visible (UV–Vis) spectrophotometer and colorimeter, respectively. Based on the results, there were significant differences (p < 0.05) for both total color changes (∆E) and L*a*b color system of the pH-sensitive edible film in different pH buffers. It indicated that the AC incorporated edible films were able to exhibit color changes over a wide range of pH. The potential application of the pH-sensitive film in spoilage detection was then carried out. Color changes of the film in commercial pasteurized milk were measured at predetermined intervals (24, 48, and 72 h) under storage conditions of 25 °C. Meanwhile, milk samples were collected for the microbiological test [total plate count (TPC)]. Results showed that the pH-sensitive films were able to detect pH changes of pasteurized milk which was associated with milk spoilage with visually observable color changes from deep blue to a light blue and showed a significant ∆E (p < 0.05) of 19.95 ± 0.009. The ∆E of the films in spoilage detection has a significant correlation with the pH changes of milk (R = − 0.9932) and TPC with a desirable coefficient (R = 0.9918). Therefore, the pH-sensitive edible film can provide a highly sensitive and non-destructive way of monitoring the food quality or spoilage without creating safety issues in the food industry. [ABSTRACT FROM AUTHOR]

Extending shelf-life of food, ensuring it is safe for consumers and meeting regulatory standards is the food industry's governing principle. Food safety is an essential aspect of food processing. Spores-forming microbes such as Bacillus spp. and Clostridium spp. are problematic in the food industry because of their ability to form endospores and survive processing conditions. Hence, their germination in food poses a threat to both shelf-life and safety of food. This paper reports on the current state of supercritical fluid carbon dioxide (SF-CO2) application in the inactivation of spores-forming microbes in food. Unlike high hydrostatic pressure and thermal processes which struggle to deactivate and destroy spores, and if they do, it impacts adversely on the food nutritional and quality attributes. This technique is viable to inactivate spores and maintain the foods structural and nutritional characteristics. The mechanisms of inactivation can be grouped into: (1) release of cellular content due to rupture of the cell wall, coat and cortex, and disruption of membranes, (2) degradation of proteins as a result of interaction with permeated and penetrated SF-CO2 and (3) deactivation of enzymatic activities. It was discovered that the synergistic effect of ultrasound another non-thermal technique or addition of co-solvent such as water, hydrogen peroxide and ethanol or antimicrobial peptide greatly enhanced inactivation of spores. This work harmonizes published perspectives on spores' inactivation mechanisms, and will help inform further research into the application of SF-CO2 in the sterilization of food products. [ABSTRACT FROM AUTHOR]

Cellulose-based bioplastics with degradability and remarkable mechanical performance have recently attracted increasing attention. As a high-performance material, cellulose-based bioplastics have a strong potential to replace synthetic plastic substrates in many applications. However, its poor shielding performance to UV light limit its application. In this work, transparent and UV-blocking MIL-68(In)-NH2@cellulose bioplastic (M(In)CBP) sheets are fabricated via a featured processing method, i.e., cellulose liquefaction, rapid solidification, in-situ synthesis and hot-press drying. The as-obtained functional bioplastic sheet (M(In)CBP1) exhibits high visible-light transparence (74.7% a 600 nm) and the existence of MIL-68(In)-NH2 allows superior UV-blocking ability (below 400 nm, transmittance was under 4%). The M(In)CBP sheets show high photostability even after continuous UV irradiation (365 nm) for over 12 h. The superior UV-shielding performance is attributed to the uniform distribution and the high UV absorbance of MIL-68(In)-NH2 in M(In)CBP sheets. High resistance to penetration by aqueous/nonaqueous liquids was proved. Moreover, the M(In)CBP sheets also show excellent mechanical properties and thermal stability. The present work designed a UV-blocking bioplastic constructed from cellulose and MIL-68(In)-NH2, which is potential candidates to replace synthetic plastics in many advanced applications such as a UV protection layer for electronic products, or useful as packaging materials to prevent food spoilage. [ABSTRACT FROM AUTHOR]

Microbial food spoilage is an important cause of health and economic issues and can occur via resilient contamination of food surfaces. Novel technologies, such as the use of visible light, have seen the light of day to overcome the drawbacks associated with surface disinfection treatments. However, most studies report that photo-inactivation of microorganisms with visible light requires long time treatments. In the present study, a novel light electroluminescent diode (LED)-based device was designed to generate irradiation at an ultra-high power density (901.1 mW/cm2). The efficacy of this technology was investigated with the inactivation of the yeast S. cerevisiae. Short-time treatments (below 10 min) at 405 nm induced a ~4.5 log reduction rate of the cultivable yeast population. The rate of inactivation was positively correlated to the overall energy received by the sample and, at a similar energy, to the power density dispatched by the lamp. A successful disinfection of several food contact surfaces (stainless steel, glass, polypropylene, polyethylene) was achieved as S. cerevisiae was completely inactivated within 5 min of treatments. The disinfection of stainless steel was particularly effective with a complete inactivation of the yeast after 2 min of treatment. This ultra-high irradiance technology could represent a novel cost- and time-effective candidate for microbial inactivation of food surfaces. These treatments could see applications beyond the food industry, in segments such as healthcare or public transport. Key points: • A novel LED-based device was designed to emit ultra-high irradiance blue light • Short time treatments induced high rate of inhibition of S. cerevisiae • Multiple food contact surfaces were entirely disinfected with 5-min treatments [ABSTRACT FROM AUTHOR]

Colorimetric sensor was successfully prepared from office waste paper-based composite. Chitosan film was coated onto surface in order to ensure the dimensional stability and reduce the water adsorption. 0.1%w/v of methyl red was employed as a sensing element. Fourier transform infrared confirmed that chitosan and methyl red were attached on the surface of cellulose. No significant change of crystallinity was observed. Morphological properties of cellulose-based composite were randomly oriented. Chitosan and methyl red were integrated in porous network. The existence of nitrogen atom was reported by Energy dispersive analysis. This element can be used to determine the position of chitosan and methyl red. Paper based composite was thermally stable up to 300 ºC. The roughness of surface was estimated to be 10–12 micron. Intensity of color was slightly enhanced when composite was attached to vapor of biogenic amine. It can be observed for 8 h. It was remarkable to note that office waste paper can be employed as a substrate in colorimetric sensor for food spoilage detection. [ABSTRACT FROM AUTHOR]

Sophorolipids are glycolipid biosurfactants produced by the yeast Starmerella bombicola. They have great potential for application in the food industry due to their several surfactant properties, highlighting the antimicrobial activity. Therefore, the objective of this work was to develop, for the first time, active films based on cassava starch with antimicrobial properties by the incorporation of sophorolipids. Films were produced by the casting method and four formulations were prepared with different proportions of cassava starch: sophorolipids: 100:0, 98:2, 95:5 and 90:10. Microstructure, barrier, mechanical and antimicrobial properties were evaluated towards the addition of sophorolipids. The obtained films showed a good appearance, without bubbles or cracks and evident changes were observed with the addition of sophorolipids, indicating a good incorporation and interaction with the polymeric matrix. The films were thermostable, more flexible, and presented promising antifungal activity against the food spoilage fungus Botrytis cinerea, which are interesting features for application in food packaging for the control of foodborne pathogens. [ABSTRACT FROM AUTHOR]

Spores of many species of the orders Bacillales and Clostridiales can be vectors for food spoilage, human diseases and intoxications, and biological warfare. Many agents are used for spore killing, including moist heat in an autoclave, dry heat at elevated temperatures, UV radiation at 254 and more recently 222 and 400 nm, ionizing radiation of various types, high hydrostatic pressures and a host of chemical decontaminants. An alternative strategy is to trigger spore germination, as germinated spores are much easier to kill than the highly resistant dormant spores—the so called "germinate to eradicate" strategy. Factors important to consider in choosing methods for spore killing include the: (1) cost; (2) killing efficacy and kinetics; (3) ability to decontaminate large areas in buildings or outside; and (4) compatibility of killing regimens with the: (i) presence of people; (ii) food quality; (iii) presence of significant amounts of organic matter; and (iv) minimal damage to equipment in the decontamination zone. This review will summarize research on spore killing and point out some common flaws which can make results from spore killing research questionable. [ABSTRACT FROM AUTHOR]

The sterols, hydrocarbons and fatty acids constituents of the leaves of five mango cultivars locally implanted in Egypt were identified. The effect of their essential oils (EOs) against food borne microorganisms was studied as preservative materials. The chemical constituents of the EOs isolated from mango leaves were identified by Gas Chromatography–Mass spectrometry (GC–MS) technique. Trans-caryophyllene, α–humulene and α–elemene were identified as terpene hydrocarbons, while 4-hydroxy-4-methyl-2-pentanone as oxygenated compounds were recorded in all tested cultivars with variable amounts. Results showed that Staphylococcus aureus and Escherichia coli were the most sensitive microorganisms tested for Alphonso EOs. On the other hand, Salmonella typhimrium was found to be less susceptible to the EOs of the studied cultivars. The EOs of different mango cultivars induced a steady decrease in the activity of amylase, protease and lipase at the minimum inhibitory concentration (MIC). The treatment of the tested bacteria with the EOs of mango cultivars caused a steady loss in enterotoxins even when applied at the sub-MIC. Bacteria-inoculated apple juice treated with minimum bactericidal concentration of Alphonso oil was free from the bacteria after 5 days of incubation at 25 °C. Eighteeen volatile compounds were found to reduce the activity of the amylase enzyme and the most active was cedrelanol (−7.6 kcal mol−1) followed by alpha-eudesmol (−7.3 kcal mol−1) and humulene oxide (−7 kcal mol−1). The binding mode of both of cedrelanol and alpha-eudesmol with amylase enzyme was illustrated. [ABSTRACT FROM AUTHOR]

With the recent advancement of next-generation sequencing methods, there has been an increase in studies on identification of vineyard microbiota, winery-associated microbiota, and microbiota in wine fermentation. However, there have been few studies investigating the fungal microbiota of table grapes which present distinct spoilage and food safety challenges. The aims of this study were to identify and compare the impact of year, variety, and vineyard location on grape, leaf, and soil fungal communities of two varieties of table grapes, Faith and Gratitude, grown in two open-air vineyards and one high tunnel vineyard. The grape, leaf, and soil mycobiota were analyzed using high throughput amplicon sequencing of the ITS region. The sampling year and location of table grapes had an impact on grape, leaf, and soil mycobiota. Fungal diversity of grape, leaf, and soil was greater in 2017 than in 2016. Grape and leaf samples presented strong similarities in fungal communities with abundance of Sporidiobolaceae and Filobasidium in two vineyards and Cladosporium in another one. The high tunnel structure had distinct grape and leaf fungal communities compared to the two other vineyard locations. Mortierella was the predominant genus (27%) in soil samples for the three locations; however, genera of lower abundance varied between locations. These results provide extensive description of fungal communities in less-studied table grape vineyards and high tunnels, providing useful insight of potential threats and preventive strategies to help improve the production and marketability of table grapes. [ABSTRACT FROM AUTHOR]

Cold plasma has proven itself as a promising method of food preservation by controlling food spoilage bacteria at very low temperatures. It is showing potential for insect control. Synthetic pesticides are mostly used to control Callosobruchus chinensis L. (Chrysomelidae: Coleoptera) to which it has developed resistance. The prospective potential of cold plasma treatment to control pulse beetle infestation of chickpea in the storage for about four years of plasma treatment was studied. The four chickpea cultivars were treated with cold plasma at different power 40, 50, and 60 W each for 10, 15, 20 min. Plasma treated and untreated chickpeas were stored in an airtight ziplock pouch. At regular intervals, the grains were observed for infestation. It was found most effective in controlling the pulse beetle infestation of treated chickpea samples. While plasma untreated chickpeas were attacked and damaged mostly by pulse beetle within the first quarter of the storage study. To avoid the problems created by the use of pesticides cold plasma treatment is found to be the best alternative in the protection of chickpea invasion by pulse beetle during a longer storage period. The findings in the present research may be used for the preparation of legumes which may also soak and cook faster like quick-cooking legumes and preserved for years without invasion of pulse beetle. [ABSTRACT FROM AUTHOR]