Plant essential oil nanocarriers: Preparation strategies, antibacterial mechanisms and food preservation applications.

Metal Organic Frameworks (MOFs) are a unique family of tailor-made porous materials that have gained significant attention for their properties and their applications in various fields, including agriculture and agrifood. The aim of this review is to explore the potential of MOFs as smart carriers and delivery mediums of essential oils (EOs) and/or aromatic volatiles. Emphasis is given to their potential to be applied in crop protection and fresh food preservation. MOFs indeed present highly promising physicochemical characteristics in order to be applied in such sectors. To name a few, their high surface area, tunable porosity, and customizable functionalities, make them ideal carriers for EOs, which are established for their antimicrobial properties but their wider practical applications are limited by their volatility and chemical sensitivity. The encapsulation of EOs in MOFs enhances their stability, controlled release, and bioavailability, providing effective solutions for sustainable agriculture and food safety. Furthermore, in this review we discuss various MOF types, emphasizing the most recent literature references, including cyclodextrin-based MOFs, Cu2+ based MOFs, Zn2+ based MOFs as well as Zr4+ MOFs. In this work, we attempt to highlight the interactions and physicochemical characteristics (e.g., pore size and pore functionality), that contribute to the encapsulation of different EOs within MOFs. We focus on a detailed discussion of the external stimuli that can trigger the targeted release of EOs, such as pH changes caused by pathogenic microbial activity. Additionally, we examine the potential benefits of the EOs encapsulation in MOFs, including the reduction of premature evaporation due to their volatile nature and their improved delivery to targeted sites. These aspects are explored within the frameworks’ food safety enhancement, extended shelf life and the promotion of sustainable food preservation alternatives. Furthermore, we address MOFs’ limitations such as biocompatibility, scalability and chemical stability under field conditions to further comprehend their potential as EO carriers in agrifood applications, emphasizing food preservation and protection. Finally, this work aims to contribute to global challenges in nutrition and sustainable agriculture.

The increasing demand for natural bioactive compounds in agriculture, food preservation, and pharmaceuticals has highlighted the need for effective delivery systems to enhance their stability and bioavailability. In this study, we address this challenge by developing and characterizing silica hollow nanospheres (HNSs) and hollow polymer nanocapsules (HPNs) for the encapsulation of essential oils (EOs), specifically those derived from Thyme (Thymus vulgaris) and Sage (Salvia officinalis). The HNSs were synthesized using tetraethyl orthosilicate (TEOS) via a sol-gel process, while urea-formaldehyde HPNs (UF–HPNs) were fabricated through in-situ polymerization. The qualitative encapsulation efficiency, structural integrity, and release behavior of the EOs were analyzed using Fourier transform infrared spectroscopy (FT–IR), field emission scanning electron microscopy (FE–SEM), and dynamic light scattering (DLS). The results demonstrated that HNSs, particularly those synthesized via in-situ techniques, exhibited superior size uniformity, higher oil loading capacity (4.18 mg/g), and controlled release performance over 102 days. Adsorption studies revealed that HNSs provided higher adsorption capabilities for Thyme EO, aligning with the Freundlich and Temkin isotherm models. Antimicrobial studies revealed that encapsulated Thyme EO exhibited strong antibacterial activity, with MIC values of 4 µL/mL against Escherichia coli (E. coli) and 2 µL/mL against Staphylococcus aureus (S. aureus), while Sage EO required higher concentrations, with MIC values of 8 µL/mL and 4 µL/mL, respectively. Notably, the encapsulation of Thyme EO in HNSs resulted in enhanced antimicrobial performance compared to HPNs, likely due to the porous silica matrix allowing for sustained EO release. The encapsulated EOs also modulated peroxidase enzyme activity, further supporting their potential for biological applications. These findings suggest that HNS-based encapsulation offers a robust and sustainable approach for enhancing the efficacy of natural antimicrobial agents, making them suitable for industrial applications in biopesticides, food safety, and therapeutic formulations.

The Sustainable Development Goals (SDGs) emphasize the importance of food safety, prolonged shelf life, and reduced food waste, all of which rely on effective food preservation methods. Bacteriocins, natural antimicrobial substances produced by lactic acid bacteria (LAB), have potential applications in food preservation. This review highlights the role of LAB-derived bacteriocins in preserving food. Bacteriocins are highly effective against foodborne infections because they target cell membranes, break down enzymes, and interfere with cellular activities. The following study used molecular docking to understand the interaction of bacteriocins and their mode of action. With their natural origin and specific action, bacteriocins offer a promising strategy for preventing foodborne diseases and extending shelf life without impacting sensory characteristics. However, challenges such as stable manufacturing, regulatory hurdles, and cost effectiveness hinder the wide adoption of bacteriocins. Nevertheless, LAB-derived bacteriocins offer a safe and efficient approach to improving food preservation, enhancing food safety, and reducing reliance on artificial preservatives. Moreover, immobilized bacteriocins have the potential to be integrated into antimicrobial packaging films, providing a targeted way to reduce the risk of foodborne pathogen contamination and improve food safety. Exploring novel bacteriocins presents exciting opportunities for advancing food preservation and safety. The present study also highlights recent advancements in food preservation through bacteriocins.

IFST Winning Articles

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

Food safety is a critical global health concern, as the consumption of unsafe food can lead to various acute and chronic diseases. While various preservation methods are employed to prevent food spoilage, it remains a significant issue for the food industry, resulting not only in food waste but also significant economic losses for manufacturers and consumers alike. Furthermore, there is growing consumer concern regarding food quality and safety, leading to the rejection of chemical additives due to their associated health risks. Organic acids, naturally occurring compounds of plants and animals, and produced by various beneficial microorganisms, play an important role in enhancing food flavor, preserving nutritional quality, and extending the shelf life of food products. Recognized for their antimicrobial potential, organic acids are commonly utilized as food preservatives, thus contributing to food safety. This review focuses on organic acids as natural preservatives within the food industry. It delves into their chemical structures, mode of action in cells, the types commonly used in preservation along with their general properties, and their antimicrobial activity against bacteria, yeasts, and fungi. These insights are drawn from the published literature, providing comprehensive understanding of the role organic acids play in ensuring food safety and maintaining food quality.

Background: Multidrug-resistant (MDR) pathogens pose a significant threat to aquatic food systems and water safety. In response, functional food science increasingly focuses on bioactive compounds derived from natural sources for food preservation and safety applications. Objectives: This study aims to investigate the antimicrobial efficacy of biogenic silver-copper-oxide nanocomposites (Ag-CuO NCs) as functional food safety agents. Methods: Biogenic Ag-CuO nanocomposites were synthesized using aqueous extracts from locally sourced botanicals at Prince Abubakar Audu University. Antimicrobial activity was evaluated against six multidrug-resistant (MDR) environmental pathogens commonly found in aquatic ecosystems (Vibrio parahaemolyticus, Escherichia coli, Salmonella enterica, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus) using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Synergistic effects with conventional food preservation methods were also assessed. Biomarker analysis included quantification of reactive oxygen species (ROS) production and assessment of membrane integrity disruption using flow cytometry and scanning electron microscopy (SEM). Results: Biogenic Ag-CuO nanocomposites demonstrated significant antimicrobial activity, with MIC values ranging from 2.5–15 μg/mL across all tested pathogens. The nanocomposites exhibited predominantly bactericidal activity. V. parahaemolyticus was the most susceptible (MIC: 2.5 μg/mL), whereas S. aureus displayed the highest resistance (MIC: 15 μg/mL). ROS quantification revealed a significant elevation in treated bacterial cells (p < 0.001), indicating oxidative stress-mediated antimicrobial mechanisms. SEM imaging confirmed cellular membrane disruption in all treated organisms. Furthermore, synergistic applications with a mild thermal treatment (50°C) enhanced antimicrobial efficacy by 3.8-fold, positioning these nanocomposites as adjuvant agents for food safety. Conclusions: Biogenic Ag-CuO nanocomposites exhibit promising functional antimicrobial properties relevant to food safety applications in aquatic food systems. Their natural derivation, dual-metal composition, and non-toxic profile at therapeutic concentrations suggest viability as bioactive food-grade safety compounds. Novelty of the Study: This study is among the first to systematically evaluate biogenic silver-copper oxide nanocomposites as functional food safety agents against multidrug-resistant aquatic pathogens, combining traditional food safety science with green nanotechnology to create novel bioactive food preservation solutions. The integration of mechanistic characterization (ROS quantification and cellular imaging), pathogen panel testing (six clinically relevant MDR organisms), and synergistic evaluation with mild thermal processing represents an original contribution advancing functional food antimicrobial applications. Keywords: functional foods, biogenic nanocomposites, antimicrobial agents, aquatic pathogens, food safety, bioactive compounds, multidrug-resistant bacteria

Essential oils encapsulated in polymer-based nanocapsules as potential candidates for application in food preservation

ABSTRACTZataria multiflora is a plant belonging to the Laminaceae family that grows in Iran, Pakistan and Afghanistan. Although artificial neural network is a sophisticated novel method in predictive microbiology, no study has been fulfilled on Z. multiflora. Therefore, the present study is undertaken to predict the effects of Z. multiflora essential oil (EO), temperature and pH on the probability percentage of growth initiation of Staphylococcus aureus using artificial neural network. For validating the artificial neural network, we used test data which were not utilized for training. For determining the ability of artificial neural network, we obtained the Pearson's correlation between artificial neural network output and experimental log P% (r = 0.998 and P < 0.0001). In conclusion, taking into consideration the importance of S. aureus in food microbiology and the antimicrobial effects of the EOs which are commonly used for flavoring, the development of artificial neural network models are beneficial in order to predict the effects of Z. multiflora EO, temperature and pH on the probability percentage of growth initiation of S. aureus.PRACTICAL APPLICATIONS Staphylococcus aureus is an important pathogen in food safety. Staphylococcal food poisoning is widespread and quite frequent. It is also among the four most common causes of foodborne illnesses. One of the most important purposes of food safety is inhibition of this microorganism growth.Substitution of traditional food preservatives by natural ones is a growing interest in food safety. Essential oils are aromatic oily liquid obtained from plant material. Plant essential oils (EOs) have varying degrees of antimicrobial activity. On the other hand, predictive microbiology is an essential element of modern food microbiology and offers to provide a scientific foundation to meet the ongoing needs of food safety. Over the last few years, artificial neural networks have been proposed as nonlinear modeling techniques in predictive microbiology.

Preventive Strategy Against Infectious Diarrhea—A Holistic Approach

Plant essential oils are volatile compounds that have been widely used in perfumery, aromatherapy, cosmetics, and for flavoring food and drink, and to a lesser extent, been used in food preservation, in medicine and household cleaning products. Essential oils and their major components are generally recognized as safe (GRAS), and because of their diverse biological activities, are focus of many studies looking for alternative agents to control bacteria, fungi and viruses in foods, crops, humans and animals. Monoterpenoids and phenylpropanoids are the major and perhaps the most important components of the various essential oils. These natural products have been proven to be a good source of antibacterial agents, particularly against food-borne pathogenic bacteria such as Escherichia coli, and Salmonella typhimurium. Essential oils or their major components have the potential to play an important role in food safety. They may also be used to control fungal decay of food, extending the shelf life of fresh produce and contributing to safer food by inhibiting the growth and mycotoxins production of important food-, feed- and soil-borne plant fungal pathogens. The antiviral and antifungal activity of certain essential oils and their components against human diseases provide a safe alternative to the synthetic drugs, particularly in immunocompromised individuals.

Fungal and mycotoxin contaminations are one of the major threats to food security. Looking into the harmful effects of synthetic preservatives, consumers currently prefer to use safer alternatives for food preservation in order to enhance the shelf life of food commodities such as green preservatives. In this context, plant essential oils (EOs) and their bioactive components are gaining prime attention in food preservation to be used as green preservatives due to their broad bioactivity as well as biodegradable nature, favourable safety profile, diverse mode of action and recognition under Generally Recognized As Safe (GRAS) Category. The nanoencapsulation technique would effectively boost the large-scale application of essential oils as food preservatives through the controlled release of bioactive components. The present review presents the recommendations for essential oils and their nanoformulations as sustainable and consumer-friendly approach to ensuring food safety by reducing mould and mycotoxin contamination.

Aromatic plants have been used since ancient times for their medicinal properties, including potent antimicrobial activity. Strong evidence indicates that plant extracts, in general, and essential oils (EOs), in particular, can act as effective antimicrobial agents against a wide spectrum of pathogenic microorganisms. However, their poor water solubility and stability, as well as their high volatility, make the administration of EOs to achieve the desired therapeutic effects particularly challenging. Therefore, these features severely limit the application of EOs in the pharmaceutical field. In this context, nanotechnology-based strategies for developing nano-scaled carriers for the efficient delivery of EOs might offer potential solutions. In particular, considering the lipophilic nature of EOs, lipid-based nanocarriers represent the most suitable vehicles for the effective encapsulation and delivery of EOs. This chapter provides an overview of the different chemical compositions due to various endogenous and/or exogenous factors of a selection of oils and the most recent lipid-based encapsulation strategies to enhance their antimicrobial activity and promote their pharmaceutical application.<br>

Antimicrobial potential of spray drying encapsulated thyme (Thymus vulgaris) essential oil on the conservation of hamburger-like meat products

The growing consumer demand for natural food preservatives has intensified research into bacteriocins, due to their potential to enhance food safety and preservation. This study aimed to conduct a bibliometric analysis of bacteriocin research from 2003 to 2023, focusing on their applications in food preservation to identify critical trends, challenges, and future directions. The analysis revealed a significant publication increase with an annual growth rate of 9.89% with countries like China, Brazil, and India as the leaders in contributions. Also, journals like “Food Control” and “Journal of Applied Microbiology” were major dissemination platforms. The research predominantly fell under Food Science Technology and Microbiology, with foundational studies by Leverentz et al. and Hammami et al. receiving high citations. Despite challenges such as pH sensitivity, thermal stability, and regulatory hurdles, advances in nanotechnology and collaborative global research are enhancing bacteriocin stability and efficacy. The study also identified emerging research themes, including integrating bacteriocins into antimicrobial packaging and their combination with other antimicrobial agents. The findings underscore the potential of bacteriocins as natural preservatives, driven by consumer demand for minimally processed foods and the need for sustainable food preservation strategies. In conclusion, while bacteriocins show promise, overcoming application and regulatory challenges is necessary for their broader integration into food safety strategies, aligning to promote sustainable and effective food preservation solutions.