Abstract In this study, cinnamon (Cinnamomum zeylanicum), thyme (Thymus vulgaris) and Schinus molle essential oils (at 125, 250 and 500 µg/mL) were encapsulated in chitosan nanoparticles by ionotropic gelation. Their antimicrobial activity against Staphylococcus aureus ATCC 25923, Enterococcus sp., Escherichia coli ATCC 25922, Klebsiella pneumoniae (BLEE +) and Pseudomona aeruginosa carbapenemase producer was evaluated. The obtained nanoparticles exhibited a regular distribution and spherical shape with size range of 19.7 to 361 nm as observed by using a laser light scattering equipment. It was found that the studied chitosan nanoparticles with essential oils showed high antimicrobial effect than the chitosan and essential oils alone. Enterococcus sp. was the most sensitive bacteria and S. aureus the most resistant. Chitosan nanoparticles and chitosan nanoparticles with cinnamon and thyme essential oils were capable to inhibit growth of Enterococcus sp. and K. pneumoniae. This study demonstrated that chitosan nanoparticles with essential oils were effective against some foodborne pathogens.

Abstract Aspergillus and Fusarium are the fungi genera most frequently isolated from cereal grains and other commodities. They are capable of producing mycotoxins, which can affect the human and animal health. Synthetic fungicides have been used to control these fungi, nevertheless, they have acquired resistance and other alternatives are necessary since they now need higher amounts. Therefore, the aim of this study was to evaluate the efficacy of cinnamon, clove and thyme essential oils (EOs) alone and encapsulated in chitosan on the radial growth, spore germination and mycotoxin production by Fusarium verticillioides and Aspergillus parasiticus. The composition of the EOs was determined by gas chromatography mass spectrometry (GC-MS). EOs inhibited radial growth and spore germination of both fungal species better than when they were encapsulated, plus, they reduced mycotoxin production. The major components were eugenol in cinnamon and clove EO (70 and 63%, respectively) and 2-methyl-5-(1-methyethyl)-phenol (46.2%) in thyme EO. The microparticles with clove and thyme EO showed good surface charges, higher than +30 mV and their average size for the three types of microparticles was about 750 nm. Our findings suggest that EOs both alone and encapsulated in chitosan have a fungistatic effect on Fusarium verticillioides and Aspergillus parasiticus.

Abstract Essential oils (EO) of eucalyptus (Eucalyptus globulus L.), thymus (Thymus capitatus L.) pirul (Schinus molle L.) were evaluated for their efficacy to control Aspergillus parasiticus and Fusarium moniliforme growth and their ability to produce mycotoxins. Data from kinetics radial growth was used to obtain the half maximal inhibitory concentration (IC50). The IC50 was used to evaluate spore germination kinetic and mycotoxin production. Also, spore viability was evaluated by the MTT assay. All EO had an effect on the radial growth of both species. After 96 h of incubation, thymus EO at concentrations of 1000 and 2500 µL L–1 totally inhibited the growth of F. moniliforme and A. parasiticus, respectively. Eucalyptus and thymus EO significantly reduced spore germination of A. parasiticus. Inhibition of spore germination of F. moniliforme was 84.6, 34.0, and 30.6% when exposed to eucalyptus, pirul, and thymus EO, respectively. Thymus and eucalyptus EO reduced aflatoxin (4%) and fumonisin (31%) production, respectively. Spore viability was affected when oils concentration increased, being the thymus EO the one that reduced proliferation of both fungi. Our findings suggest that EO affect F. moniliforme and A. parasiticus development and mycotoxin production.