In this study, Listeria monocytogenes from minced pork was evaluated for changes in resistance to thermal treatment and gastric fluid following environmental stresses during food processing. Bacteria were exposed to cold stress, followed by successive exposures to different stressors (lactic acid (LA), NaCl, or Nisin), followed by thermal treatments, and finally, their gastrointestinal tolerance was determined. Adaptation to NaCl stress reduced the tolerance of L. monocytogenes to subsequent LA and Nisin stress. Adaptation to LA stress increased bacterial survival in NaCl and Nisin-stressed environments. Bacteria adapted to Nisin stress showed no change in tolerance to subsequent stress conditions. In addition, treatment with NaCl and LA enhanced the thermal tolerance of L. monocytogenes, but treatment with Nisin decreased the thermal tolerance of the bacteria. Almost all of the sequential stresses reduced the effect of a single stress on bacterial thermal tolerance. The addition of LA and Nisin as a second step of stress reduced the tolerance of L. monocytogenes to gastric fluid, whereas the addition of NaCl enhanced its tolerance. The results of this study are expected to inform processing conditions and sequences for meat preservation and processing and reduce uncertainty in risk assessment of foodborne pathogens due to stress adaptation.

Traditional ice is usually employed to preserve food freshness and extend shelf life. However, ice cannot bear repeated freeze - thaw cycles during the transportation and retailing process, resulting in microbial cross-contamination and spoilage of foods. Herein, succinoglycan riclin was oxidated (RO) and crosslinked with gelatin (Ge), the Ge-RO cryogels were prepared via Schiff base reaction and three freeze - thaw cycles. The Ge-RO cryogels showed improved storage modulus (G\') and thermal stability compared with pure gelatin hydrogel. The polymer framework of Ge-RO gels exhibited stable properties against ice crystals destructions during nine freeze - thaw treatments. During the storage and repeated freeze - thaw treatments of shrimps, Ge-RO cryogels exhibited a remarkable preservation effect on shrimps, and their freshness was evaluated using an electronic nose technique equipped with ten sensors. The results demonstrated that the shrimp muscle preserved in ice generated off-odors and resulted in high sensor responses. The sensor responses were reduced sharply of shrimps preserved in cryogels. Moreover, 1H NMR-based metabolomics analysis revealed that shrimps in Ge-RO cryogels group reversed the metabolic perturbations compared with the traditional ice group, the metabolic pathways were related to energy metabolism, nucleotide metabolism, and amino acid metabolism, which provide new clues to the freshness of shrimps. Furthermore, RO exhibited superior antimicrobial activity against E. coli and S. aureus microorganisms. Thus, the crosslinked cryogels are potentially applicable to food preservation, offering sustainable and reusable solutions against traditional ice.

Multifunctional green food packaging films were developed by incorporating Koelreuteria paniculata Laxm. bract extract (KBE) and bio-waste-derived Ti-doped carbon dots (Ti-CDs) into a chitosan/locust bean gum (CG) matrix for the first time. Results from FTIR and XRD demonstrated the precise bonding of Ti-CDs to CG through a Schiff base reaction and hydrogen bonding, while KBE was effectively immobilized within the film matrix via hydrogen bonding. SEM and TGA analysis demonstrated enhanced thermal stability and density of the films. Addition of Ti-CDs synergistically improved the barrier properties and mechanical strength of the films through enhanced hydrogen bonding and Schiff base reactions. Specifically, the incorporation of 3 wt% Ti-CDs increased the oxygen barrier properties, tensile strength, water resistance, and vapor permeability of CG films by approximately 1.18, 0.75, and 1.51 times, respectively. Furthermore, the antimicrobial and antioxidant capabilities were significantly improved with the addition of KBE to films. The CG-3%CDs-KBE film coating effectively prolonged the shelf life of strawberries. Additionally, these films exhibited superior pH responsiveness and ammonia-sensitivity, enabling visual monitoring of shrimp freshness during storage. Importantly, CG-3%CDs-KBE films exhibited biodegradability in soil and displayed good biosafety. Overall, these findings underscore the promising potential of CG-3%CDs-KBE films as multifunctional green food packaging materials.

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.

Postbiotics possess various functional activities, closely linked to their source bacterial strains and preparation methods. Therefore, the functional activities of postbiotics need to be evaluated through in vitro and in vivo methods. This study aims to prepare a postbiotic and explore its antihemolytic, anti-inflammatory, antioxidant, and antibacterial activities. Specifically, a postbiotic preparation named PostbioP-6 was prepared by intercepting 1-5 kDa of Lacticaseibacillus paracasei Postbiotic-P6 fermentation broth. The results demonstrate that PostbioP-6 exhibited notable biological activities across multiple assays. It showed significant antihemolytic activity, with a 4.9-48.1% inhibition rate at 10-50% concentrations. Anti-inflammatory effects were observed both in vitro, where 8-40% PostbioP-6 was comparable to 259.1-645.4 μg/mL diclofenac sodium, and in vivo, where 3.5 and 4.0 μL/mL PostbioP-6 significantly reduced neutrophil counts in inflamed zebrafish (p < 0.05). Antioxidant properties were evident through increased reducing power (OD700 increased from 0.279 to 2.322 at 1.25-12.5% concentrations), DPPH radical scavenging activity (38.9-92.4% scavenging rate at 2.5-50% concentrations), and hydroxyl radical scavenging activity (4.66-10.38% scavenging rate at 0.5-4% concentrations). Additionally, PostbioP-6 demonstrated antimicrobial activity against two Gram-positive bacteria, eight Gram-negative bacteria, and one fungus. Furthermore, PostbioP-6 significantly inhibited the increase in peroxide value and malondialdehyde content in cookies, highlighting its potential application in food preservation. In conclusion, we prepared a novel postbiotic, termed PostbioP-6, which proved to have prominent anti-hemolytic, anti-inflammatory, antioxidant, and broad-spectrum antimicrobial activities. The multifunctional properties of PostbioP-6 position it as a potentially effective functional food supplement or preservative. In the future, further research is necessary to elucidate the precise mechanisms of action, identify the active components, and validate its biological activities in animal models or clinical trials.

To examine the impact of pre-harvest fungicide applications on the postharvest storage performance of tomato fruits, we measured the lycopene content, hardness, soluble solids content, rotting rate, and weight loss rate of the fruits, as well as conducted a sensory assessment. Protective and systematic fungicides were sprayed on tomatoes 20 days before harvest in order to prevent rotting and weight loss during storage. Our findings showed that, the fungicide-treated tomatoes had a significantly lower rotting rate of 16.00% and a weight loss rate of 3.96%. However the control group experienced 65.33% rotting rate and 6.90% weight loss rate on 12th days of storage. Out of the pre-harvest applications, \'Zineb\' a protective fungicide significantly delayed the loss of hardness and soluble solids accumulation in tomato fruits during storage, but it had no significant effect on lycopene content. On the other hand, when comparing to the examined treatment, the systemic fungicides did not have any significant effect on the postharvest storage performance of tomato fruits. Sensory evaluation results indicated that systemic fungicides improved the aroma of the fruits, while protective fungicides had a greater impact on the appearance and juiciness of the fruits. This study offers a potential novel solution for preserving fruits and vegetables which have been frequently infected by phytopathogens during storage, and consequently mitigate/reduce postharvest losses.

In recent years, how to improve the functional performance of food packaging materials has received increasing attention. One common inorganic material, nanometer zinc oxide (ZnO-NPs), has garnered significant attention due to its excellent antibacterial properties and sensitivity. Consequently, ZnO-NP-based functional packaging materials are rapidly developing in the food industry. However, there is currently a lack of comprehensive and systematic reviews on the use of ZnO-NPs as functional fillers in food packaging. In this review, we introduced the characteristics and antibacterial mechanism of ZnO-NPs, and paid attention to the factors affecting the antibacterial activity of ZnO-NPs. Furthermore, we systematically analyzed the application of intelligent packaging and antibacterial packaging containing ZnO-NPs in the food industry. At the same time, this paper also thoroughly investigated the impact of ZnO-NPs on various properties including thickness, moisture resistance, water vapor barrier, mechanical properties, optical properties, thermal properties and microstructure of food packaging materials. Finally, we discussed the migration and safety of ZnO-NPs in packaging materials. ZnO-NPs are safe and have negligible migration rates, simultaneously their sensitivity and antibacterial properties can be used to detect the quality changes of food during storage and extend its shelf life.

Iturin A (IA) encapsulated in chitosan (CS) microcapsules (IA/CS) underwent thorough physicochemical characterization using thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). SEM confirmed the smooth, spherical morphology of the IA/CS microcapsules, while FTIR revealed complex intermolecular interactions between IA and CS. TGA demonstrated thermal stability within the 0-100 °C range, while particle size analysis revealed an average diameter of 553.4 nm. To evaluate IA/CS efficacy in post-harvest grape preservation, grapes were treated with sterile water (CK), 10 g/L CS, 0.1 g/L IA/CS, and 0.1 g/L chitosan empty microcapsules (CKM), then stored at 25 °C for 16 days. IA/CS significantly reduced decay and respiration intensity by 52.3 % and 23.8 %, respectively, compared to CK. IA/CS treatment also inhibited abscission rate, weight loss, firmness reduction, total soluble solids consumption, titratable acidity consumption, polyphenol oxidase, and peroxidase activities on par with CS treatment (p > 0.05), but performed better than CK (reductions of 26.9 %, 41.2 %, 25.8 %, 27.2 %, 24.2 %, 19.4 %, and 17.4 %, respectively) and CKM (p < 0.05). Sensory evaluation confirmed that IA/CS effectively suppressed decay, slowed post-harvest metabolic activity, and maintained grape quality. Therefore, IA/CS microcapsules offer a promising method for extending grape shelf life and preserving quality.

Botrytis cinerea (B. cinerea) and Colletotrichum gloeosporioides (C. gloeosporioides) were isolated from the decaying strawberry tissue. The antifungal properties of Monarda didyma essential oil (MEO) and its nanoemulsion were confirmed, demonstrating complete inhibition of the pathogens at concentrations of 0.45 μL/mL (0.37 mg/mL) and 10 μL/mL, respectively. Thymol, a primary component of MEO, was determined as an antimicrobial agent with IC50 values of 34.51 (B. cinerea) and 53.40 (C. gloeosporioides) μg/mL. Hippophae rhamnoides oil (HEO) was confirmed as a potent antioxidant, leading to the development of a thymol-HEO-chitosan film designed to act as an antistaling agent. The disease index and weight loss rate can be reduced by 90 and 60%, respectively, with nutrients also being well-preserved, offering an innovative approach to preservative development. Studies on the antifungal mechanism revealed that thymol could bind to FKS1 to disrupt the cell wall, causing the collapse of mitochondrial membrane potential and a burst of reactive oxygen species.

The nutrients present in food are not only prone to a series of physicochemical reactions but also provide conditions for the growth and reproduction of foodborne microorganisms. In recent years, many innovative methods from different fields have been introduced into food preservation, which extends the shelf life while maximizing the preservation of the original ingredients and properties of food. In this field, there is a lack of a systematic summary of new technologies emerging. In view of this, we overview the innovative methods applied to the field of food preservation in recent 3 years, focusing on a variety of technological approaches such as antimicrobial photodynamic therapy based on nanotechnology, electromagnetic radiation sterilization based on radiation technology, and antimicrobial peptides based on biomolecules. We also discuss the preservation mechanism and the application of the different methods to specific categories of products. We evaluated their advantages and limitations in the food industry, describing their development prospects. In addition, as microorganisms are the main causes of food spoilage, our review also has reference significance for clinical antibacterial treatment.