Direct Contact Assay Inhibition of Spoilage Pathogens Through the Use of Essential Oils
Disciplines
Environmental Microbiology and Microbial Ecology | Life Sciences
Abstract (300 words maximum)
Antimicrobial resistance by bacterial and fungal pathogens has become increasingly prevalent. Overprescribing and misuse of antibiotics are attributed to this increase in resistance. Recently, public preference has shifted towards more natural sources of antimicrobials, void of synthetic chemicals and additives. A potential alternative can be found using essential oils (EOs). While more research on their efficacy needs to be performed, preliminary evidence supports the idea that essential oils disrupt bacterial growth through the disruption of the cellular membrane. Our research focused on the effects of direct contact with essential oils on representative food spoilage bacterial species. This research is an initial step in an evaluation of vapor phase EOs for extending the shelf life of the oyster mushroom, Pleurotus ostreatus. The constituent compounds that make up essential oils, such as phenols, monoterpenes, alcohols, and aldehydes exhibit antimicrobial properties that naturally defend against harmful microbes. These experiments were performed using broth microdilution techniques with six essential oils (Basil, Cinnamon Leaf, Cinnamon Bark, Clove Bud, Oregano and Thyme EOs) upon three bacterial species (Bacillus cereus, Enterobacter cloacae, and Staphylococcus aureus). This study determined the minimal inhibitory concentrations (MICs) of six essential oils when in direct contact with select bacterial species related to post harvest degradation of fresh mushrooms. Determining the lowest effective dose is a critical milestone in the development of this approach because, at higher levels, the organoleptic properties of EOs impart negative effects such as changes in texture, taste, or appearance. The results showed that with increasing concentration, the inhibition also increases, and that there was no significant difference between inhibition of essential oils between the gram positive and gram negative bacteria. In direct contact of each bacteria, Oregano, Cinnamon Bark, and Thyme yielded the strongest inhibition at the lowest concentrations, followed by Cinnamon Leaf, with lesser inhibition seen in Clove Bud and Basil.
Academic department under which the project should be listed
CSM - Ecology, Evolution, and Organismal Biology
Primary Investigator (PI) Name
Chris Cornelison
Direct Contact Assay Inhibition of Spoilage Pathogens Through the Use of Essential Oils
Antimicrobial resistance by bacterial and fungal pathogens has become increasingly prevalent. Overprescribing and misuse of antibiotics are attributed to this increase in resistance. Recently, public preference has shifted towards more natural sources of antimicrobials, void of synthetic chemicals and additives. A potential alternative can be found using essential oils (EOs). While more research on their efficacy needs to be performed, preliminary evidence supports the idea that essential oils disrupt bacterial growth through the disruption of the cellular membrane. Our research focused on the effects of direct contact with essential oils on representative food spoilage bacterial species. This research is an initial step in an evaluation of vapor phase EOs for extending the shelf life of the oyster mushroom, Pleurotus ostreatus. The constituent compounds that make up essential oils, such as phenols, monoterpenes, alcohols, and aldehydes exhibit antimicrobial properties that naturally defend against harmful microbes. These experiments were performed using broth microdilution techniques with six essential oils (Basil, Cinnamon Leaf, Cinnamon Bark, Clove Bud, Oregano and Thyme EOs) upon three bacterial species (Bacillus cereus, Enterobacter cloacae, and Staphylococcus aureus). This study determined the minimal inhibitory concentrations (MICs) of six essential oils when in direct contact with select bacterial species related to post harvest degradation of fresh mushrooms. Determining the lowest effective dose is a critical milestone in the development of this approach because, at higher levels, the organoleptic properties of EOs impart negative effects such as changes in texture, taste, or appearance. The results showed that with increasing concentration, the inhibition also increases, and that there was no significant difference between inhibition of essential oils between the gram positive and gram negative bacteria. In direct contact of each bacteria, Oregano, Cinnamon Bark, and Thyme yielded the strongest inhibition at the lowest concentrations, followed by Cinnamon Leaf, with lesser inhibition seen in Clove Bud and Basil.