Silver nanoparticles for inactivation and destruction of foodborne pathogens and spoilage microorganisms; mechanisms, efficiency and recent advances

Plant-derived antimicrobials have been extensively studied due to their strong activity against foodborne and spoilage microorganisms, as well as their availability from diverse and cost-effective natural sources. A wide range of bioactive plant compounds, including phenolics, essential oils, alkaloids, lectins, and antimicrobial peptides have demonstrated significant potential in controlling microbial contamination in food systems. This review uniquely integrates advances in the extraction, purification, and molecular characterization of plant extracts and their bioactive antimicrobial compounds, along with insights into their mechanisms of action and in silico discovery approaches. Among these diverse bioactives, phenolics, essential oils, and antimicrobial peptides have shown the most promising potential for food applications. Recent progress in molecular docking and molecular dynamics simulations has accelerated the identification and optimization of plant antimicrobials, revealing their possible roles in inhibiting quorum sensing and biofilm formation. Despite these advances, knowledge gaps remain regarding their safety, stability, and interactions within complex food matrices, which must be addressed for industrial application. Overall, this review highlights both the opportunities and challenges in employing plant-derived antimicrobials as sustainable alternatives to synthetic preservatives, aligning food safety with consumer demand for natural products.

Fresh fruits and vegetables are highly perishable and are subject to large postharvest losses due to physiological (senescence), pathologic (decay), and physical (mechanical damage) factors. In addition, contamination of fresh produce with foodborne human pathogens has become a concern. Gaseous ozone has multiple benefits including destruction of ethylene, inactivation of foodborne and spoilage microorganisms, and degradation of chemical residues. This article reviews the beneficial effects of gaseous ozone, its influence on quality and biochemical changes, foodborne human pathogens, and spoilage microorganisms, and discusses research needs with an emphasis on fruits. Ozone may induce synthesis of a number of antioxidants and bioactive compounds by activating secondary metabolisms involving a wide range of enzymes. Disparities exist in the literature regarding the impact of gaseous ozone on quality and physiological processes of fresh produce, such as weight loss, ascorbic acid, and fruit ripening. The disparities are complicated by incomplete reporting of the necessary information, such as relative humidity and temperatures at which ozone measurement and treatment were performed, which is needed for accurate comparison of results among studies. In order to fully realize the benefits of gaseous ozone, research is needed to evaluate the molecular mechanisms of gaseous ozone in inhibiting ripening, influence of relative humidity on the antimicrobial efficacy, interaction between ozone and the cuticle of fresh produce, ozone signaling pathways in the cells and tissues, and so forth. Possible adverse effects of gaseous ozone on quality of fresh produce also need to be carefully evaluated for the purpose of enhancing microbial and chemical safety of fresh produce.

IFST Winning Articles

PurposeThis paper aims to evaluate in vitro antibacterial activity of oregano essential oil against foodborne pathogens as a starting point for the use of spice as a natural preservative in food.Design/methodology/approachDisc and well‐diffusion assays were performed to investigate antibacterial activity of oregano essential oil against six bacteria strains: Bacillus cereus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella Typhimurium. Three concentrations of oregano essential oil were employed: 1.0 percent, 2.0 percent and 5.0 percent. Bacterial growth inhibition was determinate as the diameter of the inhibition zones.FindingsOregano essential oil showed antibacterial activity against spoilage microorganisms, at different concentrations, except for P. aeruginosa. There was a significant difference between methodologies only for the microorganism S. aureus. The results provided evidence of the existence of significant differences among the concentrations of oregano essential oil for each microorganism evaluated.Research limitations/implicationsAlthough the research for this paper involved only oregano essential oil, it provided a starting‐point for further investigations concerning spices as natural preservatives for food systems.Practical implicationsDisc and well‐assays were found to be simple and reproducible practical methods. Other spices, their essential oil and extracts might be researched against other micro‐organisms. Furthermore, in situ studies need to be performed to evaluate possible interactions between essential oils and compounds naturally present in food against microbial strains.Social implicationsThe imminent adoption of measures to reduce the use of additives in foods and the reduction on using such compounds.Originality/valueThis study provides insights that suggest a promising exploratory development of food natural preservative against spoilage microorganisms in food systems by the use of oregano essential oil.

Throughout history, spices have been employed for their pharmaceutical attributes and as a culinary enhancement. The food industry widely employs artificial preservatives to retard the deterioration induced by microbial proliferation, enzymatic processes, and oxidative reactions. Nevertheless, the utilization of these synthetic preservatives in food products has given rise to significant apprehension among consumers, primarily stemming from the potential health risks that they pose. These risks encompass a spectrum of adverse effects, including but not limited to gastrointestinal disorders, the disruption of gut microbiota, allergic reactions, respiratory complications, and concerns regarding their carcinogenic properties. Consequently, consumers are displaying an increasing reluctance to purchase preserved food items that contain such additives. Spices, known for their antimicrobial value, are investigated for their potential as food preservatives. The review assesses 25 spice types for their inherent antimicrobial properties and their applicability in inhibiting various foodborne microorganisms and suggests further future investigations regarding their use as possible natural food preservatives that could offer safer, more sustainable methods for extending shelf life. Future research should delve deeper into the use of natural antimicrobials, such as spices, to not only replace synthetic preservatives but also optimize their application in food safety and shelf-life extension. Moreover, there is a need for continuous innovation in encapsulation technologies for antimicrobial agents. Developing cost-effective and efficient methods, along with scaling up production processes, will be crucial to competing with traditional antimicrobial options in terms of both efficacy and affordability.

Machine Learning and Predictive Microbiology: Enhancing Food Safety Models 14The goal of food safety is to guarantee that the food provided to consumers does not represent a 15 health risk due to the presence of chemical, physical, or biological hazards. In particular, microbial 16 growth of spoilage or pathogenic microorganisms can reduce the shelf life or pose a health hazard. 17The composition, physical, and chemical properties of a food product can either promote or inhibit 18 microbial growth; also, food processing methods can favor or restrain microbial proliferation. The 19 response of microorganisms to food composition, processing, or storage conditions will determine 20 their growth capacity. Traditional microbial growth models, often used in laboratory settings, do not 21 always translate well to real-world food environments due to the unique conditions present in food 22 systems. Predictive microbiology has emerged as a valuable tool in this context, enabling researchers 23 to predict the behavior of pathogenic and spoilage microorganisms in food systems based on growth 24 results obtained under controlled conditions (Kumar et al. 2024). 25The food industry constantly modifies processing conditions, develops or enhances more efficient 26 preservation methods, and creates new food products. In all these scenarios, the use of predictive 27 microbiology can help select the best conditions to increase shelf life and reduce the risk of pathogen 28 contamination. Even when predictive models have been utilized in the food industry as a complement 29 to quality control programs, such as HACCP (Hazard Analysis and Critical Control Points), 30 numerous challenges remain in this research area. The development of new predictive primary 31 models is an ongoing task, as new variables can be incorporated and new statistical and mathematical 32 methods become available. Typically, predictive models examine the growth of an organism under 33 controlled conditions; however, the impact of interactions with other organisms present in the food 34 environment is often overlooked. Additionally, the initial physiological state of the microorganisms needs to be taken into consideration (Koseki et al., 2021). The incorporation of new information 36 provided by the "omics" sciences, particularly functional genomics, can also improve the prediction 37 of microbial growth in foods. Tools such as data mining or machine learning can utilize up-to-date 38 information on microbial growth in food systems to generate more comprehensive predictive models 39 (Taiwo et al. 2024). 40In the present Research Topic, the combination of preservation methods is reported as efficient in 41 increasing the shelf life of food products. In Chen et al (2024), the antimicrobial effect of lemon 42 essential oil alone and in nanoemulsion was tested against common foodborne pathogens 43 (Escherichia coli, Staphylococcus aureus, Listeria monocytogenes). The effect was also tested on the 44 shelf life of fresh-cut kiwifruits, showing that the increase in shelf life was related to the 45 antimicrobial and antioxidant effects of the nanoemulsion. In another study, the effect of lactic acid 46 bacteria (LAB) inoculants on the quality of oat silage was investigated, seeking to reduce the 47 concentration of biogenic amines and thereby improve product safety (Huang and Jia, 2025 was used to construct the secondary and tertiary models, which were then validated with 60 experimental data. The author emphasizes the importance of developing tertiary models that can be 61 used in the food industry. 62The incorporation of novel strategies to manage data, such as data mining, neural networks, and 63 machine learning, presents an opportunity to enhance the goals of predictive microbiology. A better 64 understanding of the physiological stages of microorganisms in food systems, along with the changes 65 in growth conditions at different steps in the food management chain, can also provide a more 66 accurate view of the effects of processing on food preservation and safety. Several questions remain 67 to be answered in this topic. 68

ABSTRACTFoodborne pathogens are critical concerns in the food safety sector and for regulatory agencies due to their high morbidity and mortality rates. They also significantly impact the economy, particularly in countries with limited financial resources. Furthermore, the rapid progression of microbial resistance to antibiotics and the hazards associated with chemical preservatives are global challenges. This underscores the importance of developing natural antimicrobial additives for the food industry. Plants offer a promising source of effective antimicrobial agents with significant activity against foodborne pathogens. In particular, phytochemicals demonstrate significant potential for improving food safety due to their broad antimicrobial properties. In this context, we reviewed the classification and extraction processes of phytochemicals, their antimicrobial activities, mechanisms of action, factors influencing their antimicrobial efficacy, and their applications in food safety. Additionally, we explored the current challenges associated with the industrial application of phytochemicals as natural preservatives. Phytochemicals have demonstrated substantial antimicrobial effects against a variety of foodborne pathogens through diverse mechanisms. Thus, they represent a promising solution for advancing the food industry and enhancing food safety.

The present work evaluated the antimicrobial potential of the ethanolic extract of jambu mawar [Syzygium jambos (L.) Alston] leaves against various foodborne pathogens and spoilage microorganisms via the disc diffusion assay (DDS) and the time-kill curve assay. These microorganisms included bacteria (Klebsiella pneumoniae ATCC13773, Listeria monocytogenes ATCC19112, Proteus mirabilis ATCC21100, Pseudomonas aeruginosa ATCC9027, Staphylococcus aureus ATCC29737, and Vibrio parahaemolyticus ATCC17802), yeasts (Candida albicans ATCC10231, C. krusei ATCC32196, C. glabrata ATCC2001, and C. parapsilosis ATCC22019), and moulds (Aspergillus fumigatus ATCC26430, A. niger ATCC9029, Rhizopus oligosporus ATCC22959, and R. oryzae ATCC22580). The inhibition zone of DDA ranged from 7.00 ± 0.23 to 10.25 ± 0.29 mm. The minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal (MBC/MFC) of the ethanolic leaf extract were obtained at the concentrations of 0.01 to 2.50 and 0.01 to 5.00 mg/mL, respectively. The time-kill curve assay showed that except for P. mirabilis, other microorganisms were completely killed at MIC concentrations ranging from 0.5 to 4× MIC. In comparison, P. mirabilis showed a growth reduction of > 3 log10 CFU/mL for 4 h. Meanwhile, the conidial germination of A. fumigatus was fully inhibited at 0.5× MIC. Though not fully inhibited, the ethanolic leaf extract significantly reduced the conidial germination of A. niger, R. oryzae, and R. oligosporus to 7.0, 7.0, and 11.0%, respectively. Overall, the ethanolic leaf extract of S. jambos exhibited antimicrobial activity against foodborne pathogens and spoilage microorganisms.

To address the increasingly serious challenge of the transmission of foodbrone pathogens in the food chain. In this study, we employed rational design strategies, including truncation, amino acid substitution, and heterozygosity, to generate seven engineered peptides with α-helical structure, cationic property, and amphipathic characteristics based on the original Abhisin template. Among them, as the hybird antimicrobial peptide (AMP), AM exhibits exceptional stability, minimal toxicity, as well as broad-spectrum and potent antimicrobial activity against foodborne pathogens. Besides, it was observed that the electrostatic incorporation demonstrates by AM results in its primary targeting and disruption of the cell wall and membrane of Escherichia coli O157: H7 (EHEC) and methicillin-resistant Staphylococcus aureus (MRSA), resulting in membrane perforation and enhanced permeability. Additionally, AM effectively counteracts the deleterious effects of lipopolysaccharide, eradicating biofilms and ultimately inducing the demise of both food spoilage and pathogenic microorganisms. The findings highlight the significant potential of AM as a highly promising candidate for a novel food preservative and its great importance in the design and optimization of AMP-related agents.

Tropical plant products as biopreservatives and their application in food safety

Food microbiology is a branch of microbiology that focuses on the study of microorganisms that are associated with food intended for human or animal consumption. Microorganisms use food as a source of nutrient for survival and growth or a vehicle of transmission to the human or animal host. Food microbiology is broadly classified into three focus areas: beneficial microorganisms, spoilage microorganisms, and pathogenic microorganisms. Beneficial microorganisms are those used for making traditional or ethnic fermented products, and as probiotics, which are gaining increased popularity because of their health-beneficial effects. Spoilage microorganisms, on the other hand, are responsible for product spoilage and place an economic burden on the producers, processors, and retail store owners for product losses. This is a serious issue in developing countries because of inadequate processing and refrigeration facilities. Foodborne pathogen contamination in foods presents a serious challenge which may result in severe diseases such as food intoxication, toxicoinfection, and infection. Mortality, morbidity, and product recalls are serious consequences of outbreaks caused by foodborne pathogens. Most foodborne pathogens grow in the mesophilic range and a few in the psychrophilic range and their growth does not usually alter the aesthetic quality of foods. Some pathogenic traits are sometimes acquired through plasmids, transposons, bacteriophages, or through pathogenicity islands. Foodborne pathogens can be zoonotic, geonotic, or human origin, and consumption of contaminated foods results in foodborne diseases. In order for a foodborne pathogen to cause disease, the microbe must be able to survive in food and, when transferred to human hosts, find niches, multiply, and express virulence factors to cause host cell damage. Worldwide, foodborne pathogens are responsible for large numbers of outbreaks, illnesses, and mortalities. Foodborne pathogens are a serious public health concern, and outbreaks are attributed to the emergence of new pathogens and reemergence of some old pathogens. The routine epidemiological and food product surveys are introduced by many countries in order to provide an accurate picture of global distribution and occurrence of foodborne diseases. The reasons for the emergence of increased foodborne diseases have been investigated. Several factors are thought to be responsible: improved survey system and the creation of the database for various pathogens; changes in agricultural and food manufacturing practices; consumer’s habits of food consumption and preparation; the increased population of the susceptible group; improved survival and adaptation of pathogens in harsh food environments; and improved detection methods. To control foodborne pathogen-related illnesses and deaths, the US government has passed the Food Safety Modernization Act (FSMA) in 2011 as a science-based proactive preventive strategy rather than a reactive passive approach to the food safety. Globally, food safety is a major concern due to increasing numbers of food- and water-associated illnesses and mortality, the emergence of highly infectious diseases from bush meats derived from wild animals, travel-associated intercontinental transfer of pathogens, and globalization of food supplies.

Essential oils (EOs) have been long recognized for their antibacterial, antifungal, antiviral, insecticidal and antioxidant properties. They are widely used in medicine and the food industry for these purposes. The increased interest in alternative natural substances is driving the research community to find new uses and applications of these substances. EOs and their components show promising activities against many food-borne pathogens and spoilage microorganisms when tested in vitro. In food systems, higher concentrations of EOs are needed to exert similar antibacterial effects as those obtained in in vitro assays. The use of combinations of EOs and their isolated components are thus new approaches to increase the efficacy of EOs in foods, taking advantage of their synergistic and additive effects. The purpose of this review is to provide an overview on the antimicrobial efficacy of these combinations. A survey of the methods used for the determination of the interactions and mechanisms involved in the antimicrobial activities of these combinations are also reported.

Growing consumer awareness of clean labels is driving demand for preservative-free products yet concerns about foodborne pathogens and microbiological safety remain significant. Plant-derived compounds with bioactive properties—phytobiotics—have emerged as promising alternatives or complements to conventional antimicrobial agents. This review discusses phytobiotics, including essential oils, polyphenols, alkaloids, and organosulfur compounds, highlighting their structural diversity and antimicrobial potential. Phytobiotics combat foodborne pathogens by disrupting cell structures, inhibiting biofilms and quorum sensing, and interfering with genetic and protein synthesis. Importantly, some phytobiotics exhibit synergistic effects when combined with antibiotics or other natural agents, enhancing overall antimicrobial efficacy. The impact of phytobiotics on the microbiota of food products and the gastrointestinal tract is also addressed, with attention to both beneficial modulation and possible unintended effects. Practical applications in food preservation and supplementation are analyzed, as well as challenges related to composition variability, stability, and interactions with food matrices. Nevertheless, modern technologies such as nanoencapsulation, complexation with polysaccharides, and advanced extraction methods are being developed to address these challenges and enhance the stability and bioavailability of phytobiotics. Continued investment in research and innovation is essential to fully harness the potential of phytobiotics in ensuring safe, natural, and sustainable food systems.

"Emerging technologies for detecting foodborne pathogens and spoilage microorganisms in milk: Ensuring safety and quality".

Chapter 33 - Antimicrobial Food Packaging Incorporated with Triclosan: Potential Uses and Restrictions