In vitro growth‐inhibitory effect of essential oils and supercritical carbon dioxide extracts from Cinnamomum spp. barks and fruits against food bacterial pathogens in liquid and vapor phase

Abstract

AbstractFoodborne microbial diseases constitute major health concern and therefore it is necessary to preserve food products to prolong their shelf life and safety. Promising method of food preservation is application of volatile natural agents into modified atmosphere in food packaging. Spices and condiments containing volatile oils could potentially be used. Antimicrobial effect of three essential oils (EOs) and three supercritical carbon dioxide extracts (CO2 extracts) from Cinnamomum barks and fruits was evaluated using broth‐microdilution volatilization method against common foodborne pathogens, namely Bacillus cereus, Escherichia coli, Listeria monocytogenes, and Salmonella enterica Typhimurium. All samples exhibited significant inhibitory effect with minimum inhibitory concentration (MIC) values ranging from 256 to 1,024 μg/ml in both liquid and vapor phase. EO from immature fruits of Cinnamomum cassia, known as cassia buds, was the most effective agent against all tested microorganisms with MIC values ranging from 256 to 512 μg/ml in both phases. Using gas chromatography–mass spectrometry analysis, E‐cinnamaldehyde has been detected as the most abundant constituent in all samples. Subsequently, the time series headspace analysis of vapors above the mixture of growth medium and C. cassia fruits EO was performed. Decreasing content of E‐cinnamaldehyde in the headspace was gradually replaced by δ‐cadinene and γ‐muurolene. Proposed mechanism behind this is ability of E‐cinnamaldehyde to pass from the headspace back to the liquid medium. Obtained results suggest that EOs and CO2 extracts from Cinnamomum spp. could be used in food industry as natural food preservatives. In addition, broth‐microdilution volatilization method has been validated for development of food applications.