Effects of three essential oils and their nano-emulsions on Listeria monocytogenes and Shigella flexneri in Egyptian Talaga cheese

The prospect of using nanotechnology to prevent and treat infections caused by Listeria monocytogenes

Listeria monocytogenes (L. monocytogenes) is an opportunistic intracellular pathogen that causes listeriosis in human and leads to high mortality rate. L. monocytogenes is resistant to various antibiotics due to its ability to form biofilm. Designing a new generation of antibiotics is a very expensive and time-consuming process. Moreover, the protection of antibiotics via drug delivery system can promote their effectiveness and bioavailability. Nanomedicine can be a promising tool for treating intracellular bacteria and preventing the recurrence of infections. Nanocarriers can be employed as antibacterial agents or as a carrier for antibacterial agents. In the present review, the application of nanotechnology has been discussed for the prevention and treatment of Listeria infection. According to the studies, the application of nanomaterials can be a potential strategy to eradicate infections caused by L. monocytogenes.

Fabrication of guar gum/chitosan edible films reinforced with orange essential oil nanoemulsion for cheese preservation

Inner Mongolian cheese is easily spoiled during storage due to hydrolysis and microbial contamination. Herein, the guar gum (GG)/chitosan (CS) edible films reinforced with orange essential oil nanoemulsion (OEON) were fabricated for cheese preservation. Results showed 4 % OEON with the optimal droplet size (380 ± 44.07 nm) and uniform distribution exhibited commendable compatibility with the GG/CS edible films, leading to an improvement in the oxygen and water vapor barrier properties, concomitantly mitigating their hydrophilic nature, with decreasing moisture content (from 96.86 % to 34.69 %) and water solubility (from 72.27 % to 69.76 %), while an increasing water contact angle (from 59.9° to 113.8°). The addition of 4 % OEON into the GG/CS edible films yielded a slight decrease in the tensile strength, but the elongation at break significantly increased to 135.12 %, indicating the improvement of mechanical properties. Moreover, the GG/CS-OEON edible films demonstrated outstanding biodegradability, thermal stability, and antimicrobial properties. Particularly, GG/CS-OEON 3:1 edible films packaging could maintain the stability of the weight loss, pH, color, and textural changes, retard the bacterial growth and delay the lipid oxidation of the cheese samples, thereby ensuring the cheese quality and safety. Findings here demonstrated the promising potential application of GG/CS-OEON 3:1 edible films in Inner Mongolian cheese preservation.

Enhancing Ras cheese safety: antifungal effects of nisin and its nanoparticles against Aspergillus flavus

BACKGROUND

Due to the adverse effects of industrial chemicals and their carcinogenicity and toxicity for humans, the debates have increased on using natural preservatives. This study was conducted to investigate the inhibitory effect of pure nisin and nisin nanoparticles (nisin NPs) against Aspergillus flavus in vivo by inoculation in laboratory-manufactured Ras cheese. A novel, safe, and natural approach of nanoprecipitation using acetic acid was employed to prepare nisin nanoparticles. The prepared NPs were characterized using zeta-sizer, FTIR, and transmission electron microscopy (TEM). Furthermore, the cytotoxicity of nisin NPs on Vero cells was assessed. The minimum inhibitory concentrations (MICs) of nisin and its nanoparticles were determined in vitro against A. flavus isolates using the agar well-diffusion method. The sensory evaluation of manufactured Ras cheese was conducted over a 60-day storage period.

RESULTS

The obtained results showed a strong antifungal activity of nisin NPs (0.0625 mg/mL) against A. flavus strain in comparison with pure nisin (0.5 mg/mL). Notably, the count decreased gradually by time from 2 × 108 at zero time and could not be detected at the 7th week. The count with pure nisin decreased from 2 × 108 at zero time and could not be detected at the 10th week where it's enough time to produce aflatoxins in cheese. The MICs of nisin and nisin NPs were 0.25 and 0.0313 mg/mL, respectively. Nisin NPs used in our experiment had good biocompatibility and safety for food preservation. Additionally, the sensory parameters of the manufactured Ras cheese inoculated with nisin and nisin NPs were of high overall acceptability (OAA).

CONCLUSIONS

Overall, the results of this study suggested that adding more concentration (˃0.0625 mg/mL) from nisin nanoparticles during the production of Ras cheese may be a helpful strategy for food preservation against A. flavus in the dairy industry.

Preparation and Characterization of Cumin Essential Oil Nanoemulsion (CEONE) as an Antibacterial Agent and Growth Promoter in Broilers: A Study on Efficacy, Safety, and Health Impact

This research characterized and explored the effect of cumin essential oil nanoemulsion (CEONE) on broiler growth performance, serum biochemistry, hematological parameters, and cecal microbial count. Day-old (n = 96) broilers (Ross 308) were randomly assigned to six treatments with five replicates of three broilers each. The dietary treatments consisted of negative control (only basal diet), positive control (basal diet + 200 µL of enrofloxacin), 25 µL (basal diet + 25 µL of CEONE), 50 µL (basal diet + 50 µL of CEONE), 75 µL (basal diet + 75 µL of CEONE), and 100 µL (basal diet + 100 µL of CEONE). The broiler's body weight gain (BWG) after 42 days of treatment exhibited increased weight in the CEONE group (976.47 ± 11.82-1116.22 ± 29.04). The gain in weight was further evidenced by the beneficial microbe load (107 log) compared to the pathogenic strain. All the biochemical parameters were observed in the normal range, except for a higher level of HDL and a lower LDL value. This safety has been validated by pKCSM toxicity analysis showing a safe and highly tolerable dose of cuminaldehyde. In conclusion, this research observed the potential of CEONE as a multifunctional agent. It is a valuable candidate for further application in combating bacterial infections and enhancing animal health and growth.

Comprehensive Review on the Biocontrol of Listeria monocytogenes in Food Products

Listeria monocytogenes is a foodborne pathogen that causes listeriosis, a group of human illnesses that appear more frequently in countries with better-developed food supply systems. This review discusses the efficacy of actual biocontrol methods combined with the main types of food involved in illnesses. Comments on bacteriophages, lactic acid bacteria, bacteriocins, essential oils, and endolysins and derivatives, as main biological antilisterial agents, are made bearing in mind that, using them, food processors can intervene to protect consumers. Both commercially available antilisterial products and solutions presented in scientific papers for mitigating the risk of contamination are emphasized. Potential combinations between different types of antilisterial agents are highlighted for their synergic effects (bacteriocins and essential oils, phages and bacteriocins, lactic acid bacteria with natural or synthetic preservatives, etc.). The possibility to use various antilisterial biological agents in active packaging is also presented to reveal the diversity of means that food processors may adopt to assure the safety of their products. Integrating biocontrol solutions into food processing practices can proactively prevent outbreaks and reduce the occurrences of L. monocytogenes-related illnesses.

Progress of nanopreparation technology applied to volatile oil drug delivery systems

Traditional Chinese medicine volatile oil has a long history and possesses extensive pharmacological activity. However, volatile oils have characteristics such as strong volatility, poor water solubility, low bioavailability, and poor targeting, which limit their application. The use of volatile oil nano drug delivery systems can effectively improve the drawbacks of volatile oils, enhance their bioavailability and chemical stability, and reduce their volatility and toxicity. This article first introduces the limitations of the components of traditional Chinese medicine volatile oils, discusses the main classifications and latest developments of volatile oil nano formulations, and briefly describes the preparation methods of traditional Chinese medicine volatile oil nano formulations. Secondly, the limitations of nano formulation technology are discussed, along with future challenges and prospects. A deeper understanding of the role of nanotechnology in traditional Chinese medicine volatile oils will contribute to the modernization of volatile oils and broaden their application value.

Potential of Essential Oils in the Control of Listeria monocytogenes

Listeria monocytogenes is a foodborne pathogen, the causative agent of listeriosis. Infections typically occur through consumption of foods, such as meats, fisheries, milk, vegetables, and fruits. Today, chemical preservatives are used in foods; however, due to their effects on human health, attention is increasingly turning to natural decontamination practices. One option is the application of essential oils (EOs) with antibacterial features, since EOs are considered by many authorities as being safe. In this review, we aimed to summarize the results of recent research focusing on EOs with antilisterial activity. We review different methods via which the antilisterial effect and the antimicrobial mode of action of EOs or their compounds can be investigated. In the second part of the review, results of those studies from the last 10 years are summarized, in which EOs with antilisterial effects were applied in and on different food matrices. This section only included those studies in which EOs or their pure compounds were tested alone, without combining them with any additional physical or chemical procedure or additive. Tests were performed at different temperatures and, in certain cases, by applying different coating materials. Although certain coatings can enhance the antilisterial effect of an EO, the most effective way is to mix the EO into the food matrix. In conclusion, the application of EOs is justified in the food industry as food preservatives and could help to eliminate this zoonotic bacterium from the food chain.

Metabolomics insights into the potential of encapsulated essential oils as multifunctional food additives

Growing consumer concern about foodborne disease outbreaks and health risks associated with chemical additives has propelled the usage of essential oils (EOs) as novel food additives, but are limited by instability. In this regard, a series of EOs nano/micro-capsules have been widely used to enhance their stability and improve food quality. However, classical food quality assessment methods are insufficient to fully characterize the effects of encapsulated EOs on food properties, including physical, biochemical, organoleptic, and microbial changes. Recently, the rapid development of high-throughput sequencing is accelerating the application of metabolomics in food safety and quality analysis. This review seeks to present the most recent achievements in the application of non-targeted metabolomics to identify and quantify the overall metabolite profile associated with food quality, which can guide the development of emerging food preservation technologies. The scientific findings confirm that metabolomics opens up exciting prospects for biomarker screening in food preservation and contributes to an in-depth understanding of the mechanisms of action (MoA) of EOs. Future research should focus on constructing food quality assessment criteria based on multi-omics technologies, which will drive the standardization and commercialization of EOs for food industry applications.

Recent advances in nutritional composition, phytochemistry, bioactive, and potential applications of Syzygium aromaticum L. (Myrtaceae)

Syzygium aromaticum is an aromatic plant native to Indonesia, and introduced to tropical regions worldwide. As an ingredient in perfumes, lotions, and food preservation, it is widely used in the food and cosmetic industries. Also, it is used to treat toothache, ulcers, type 2 diabetes, etc. A variety of nutrients such as amino acids, proteins, fatty acids, and vitamins are found in S. aromaticum. In addition to eugenol, isoeugenol, eugenol acetate, β-caryophyllene and α-humulene are the main chemical constituents. The chemical constituents of S. aromaticum exhibit a wide range of bioactivities, such as antioxidant, antitumor, hypoglycemic, immunomodulatory, analgesic, neuroprotective, anti-obesity, antiulcer, etc. This review aims to comprehend the information on its taxonomy and botany, nutritional composition, chemical composition, bioactivities and their mechanisms, toxicity, and potential applications. This review will be a comprehensive scientific resource for those interested in pursuing further research to explore its value in food.