The increase in β-lactam-resistant Gram-negative bacteria is a severe recurrent problem in the food industry for both producers and consumers. The development of nanotechnology and nanomaterial applications has transformed many features in food science. The antibacterial activity of zinc oxide nanoparticles (ZnO NPs) and their mechanism of action on β-lactam-resistant Gram-negative food pathogens, such as Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Serratia marcescens, Klebsiella pneumoniae, and Proteus mirabilis, are investigated in the present paper. The study results demonstrate that ZnO NPs possesses broad-spectrum action against these β-lactamase-producing strains. The minimal inhibitory and minimal bactericidal concentrations vary from 0.04 to 0.08 and 0.12 to 0.24 mg/mL, respectively. The ZnO NPs elevate the level of reactive oxygen species (ROS) and malondialdehyde in the bacterial cells as membrane lipid peroxidation. It has been confirmed from the transmission electron microscopy image of the treated bacterial cells that ZnO NPs diminish the permeable membrane, denature the intracellular proteins, cause DNA damage, and cause membrane leakage. Based on these findings, the action of ZnO NPs has been attributed to the fact that broad-spectrum antibacterial action against β-lactam-resistant Gram-negative food pathogens is mediated by Zn2+ ion-induced oxidative stress, actions via lipid peroxidation and membrane damage, subsequently resulting in depletion, leading to β-lactamase enzyme inhibition, intracellular protein inactivation, DNA damage, and eventually cell death. Based on the findings of the present study, ZnO NPs can be recommended as potent broad-spectrum antibacterial agents against β-lactam-resistant Gram-negative pathogenic strains.

Cashew nut shell liquid (CSNL) nanoemulsion has been formulated and its cytotoxic activity was determined using human breast cancer cells (MCF-7) adopting MTT assay and established staining techniques. MCF-7 cells treated with CSNL nanoemulsion suffered loss of viability and death mostly through apoptosis and/or necrosis as evidenced by the changes in the nuclear morphology and cytoplasmic features. The IC 50 value of 48-h treatment groups fall in the range of 88 ± 14.2 ll/ml. In conclusion, the antiproliferative and morphological effects of CSNL nanoemulsion appear to be target-specific killing of cells which gives further lead to study apoptotic pathways as target for breast cancer therapy. This study has provided a scientific basis for the anti-tumor property of CSNL nanoemulsion with respect to breast cancer.

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Nanoemulsions formulated using materials of the highest food grade are receiving significant attention in various industries, especially food-based applications. Food-grade nanoemulsions are suitable for delivering bioactive molecules and their bioavailability, encapsulation, and protection. The present study aimed to extract essential oil (EO) from clove bud and formulate food-grade nanoemulsions. Furthermore, it investigated antioxidant and antimicrobial efficacy of nanoemulsions against foodborne pathogens. The present study found that the extracted clove bud EO is enriched with polyphenols and consists of 59 bioactive compounds from various chemical groups such as alcohol, aldehyde, esters, benzenes, carboxylic acid, esters, fatty acids, and nitrogen compounds. Among the bioactive compounds, methyl eugenol was identified as a major compound. Clove bud EO nanoemulsion antioxidant and noncytotoxic results suggest that this material could help develop promising antibacterial agents for food-based applications. The formulated nanoemulsion consisting of droplets of a mean diameter of 77.7 nm exhibits significant inhibitory and bactericidal action on Gram-positive and Gram-negative food pathogens. It is still essential to conduct more studies on the effects of food spoilage and poisoning bacteria and the mechanisms of their actions.