Antimicrobial properties and mode of action of mustard and cinnamon essential oils and their combination against foodborne bacteria

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. (C) 2016 Elsevier Ltd. All rights reserved.