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BACKGROUND The ongoing postharvest loss in citrus fruits, due to fungal infection, is a chronic economic and agricultural problem. Most of citrus damage is caused by Penicillium spp., e.g. green mold ( P. digitatum) and blue mold ( P. italicum). Fungal chitosan, from Mucor rouxii, and plant extracts from cress seeds, olive leaves, pomegranate peels and senna pods, were evaluated as antifungal agents against the phytopathogenic fungi, P. digitatum and P. italicum, using in vitro qualitative and quantitative assays. RESULTS All natural agents tested exhibited potent antifungal activity; the most powerful agent was cress ( Lepidium sativum) seed extract, followed by pomegranate ( Punica granatum) peel extract. Fungal chitosan also had a remarkable fungicidal potentiality using both evaluation assays. Penicillium digitatum was generally more resistant than P. italicum toward all examined agents. The incorporation of each individual natural agent in coating material resulted in a great reduction in fungal growth and viability. The addition of chitosan combined with cress and pomegranate extracts, to the coating materials, prevented coated citrus fruit from decay by green and blue mold for a 2-week storage period. CONCLUSION Natural derivatives could be recommended as powerful antifungal alternatives to protect citrus fruits from postharvest fungal decay. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The current spreading of nanomaterial applications supports the search for further possible functions of theses diminutive particles. The antibacterial potentiality of zinc oxide (ZnO) nanoparticles (NPs), compared with conventional ZnO powder, against nine bacterial strains, mostly foodborne including pathogens, was evaluated using qualitative and quantitative assays. ZnO NP was more efficient as antibacterial agent than powder. Gram‐positive bacteria were generally more sensitive to ZnO than Gram negatives. The exposure of Salmonella typhimurium and Staphylococcus aureus to their relevant minimal inhibitory concentrations from ZnO NP reduced the cell number to zero within 8 and 4 h, respectively. Scanning electron micrographs of the treated bacteria with NPs exhibited that the disruptive effect of ZnO on S. aureus was vigorous as all treated cells were completely exploded or lysed after only 4 h from exposure. Promising results of ZnO NP antibacterial activity suggest its usage in food systems as preservative agent after further required investigations and risk assessments. PRACTICAL APPLICATIONS: Foodborne pathogen invasion is still a recurrent serious problem facing researchers and food industry overseers. The introduction of novel powerful antimicrobial agents is of great importance for the control of pathogenic bacteria, especially antibiotic‐resistant strains. Zinc oxide (ZnO) nanoparticle (NP) could be one of these potential alternatives. This study focused on ZnO NP because of its increasing presence in many marketable products and that supports its application in food industries as a reasonably safe agent. The demonstrated antibacterial activity of ZnO NP recommends its possible application in the food preservation field; otherwise it can be applied as a potent sanitizing agent for disinfecting and sterilizing food industry equipment and containers against the attack and contamination with foodborne pathogenic bacteria. [ABSTRACT FROM AUTHOR]