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The aim of this work was the study of the main effects of benzyl isothiocyanate (BITC) on A. ochraceus morphology and on its production metabolism of ochratoxins. This compound was evaluated as active agent of an antimicrobial label in food packaging. Microbiological studies showed a slowdown in mould growth when the active material was applied to A. ochraceus and the presence of three different areas of growth. Scanning electron microscopy was successfully used to demonstrate the mode of action of BITC on this strain. A. ochraceus exhibited modifications in morphology compared to the control samples such as the disappearance of sclerotia or cleistothecia An extraction protocol and an analytical method by UPLC-MS/MS to determine ochratoxins (OTs) was developed. The results showed that all these morphological changes were related to a decrease on OTs production, both ochratoxin A (OTA) and ochratoxin B (OTB). The presence of BITC caused a great decrease on OTA that modified the OTA/OTB ratio, increasing the OTB proportion. Furthermore, the active packaging also modified the production of other secondary metabolites. The morphological and metabolic effects observed, as well as the relationship between them, are of great interest since they have not been reported before for A. ochraceus . [ABSTRACT FROM AUTHOR]

In this work, the effects of cinnamon and mustard essential oils against nine foodborne bacteria were evaluated. Their antimicrobial susceptibility and action mechanism was also assessed. Additionally, the effects of the combination between both were evaluated. To provide data on the in vitro action of essential oils, the transfer mechanism was assessed using gas chromatography–mass spectrometry. The results indicated that the mustard presents 10 times more bactericidal/bacteriostatic effect than cinnamon essential oil. In both cases the action mechanism happened intracellularly, but since mustard induces cell cycle arrest, cinnamon produces protrusions and aggregation. The combinatorial assays demonstrated in most cases an additive effect. In addition, synergies for P. putida and E. coli OI57:H7 were shown. Therefore, to introduce them in combination, could be a great way to make a natural-active packaging. The distinct activity profiles can be explained by their transfer mechanism that involves vapour release and agar diffusion. Industrial relevance The industry is focused on improving food safety by controlling the growth of foodborne and food spoilage microorganisms and by reducing the use of synthetic preservatives. The novelty of this research article lies in the study of antimicrobial activity of two natural active agents (mustard and cinnamon essential oil), separately and in combination, against nine foodborne bacteria; as well as the study of its mechanism of action and transfer. The set of all outcomes give the necessary information to be able to design a novel food active packaging based on the applied microbiology studied. [ABSTRACT FROM AUTHOR]