Table 2.

Comparison of MIC values between free EOs and their active components against different types of microbial contaminations.

Microorganism	Whole EO		EO Active Components		References
	Type	MICa	Type	MIC
Gram-positive bacteria
S. aureus	Oregano	0.06–0.12%b	Carvacrol Thymol	0.01–0.03% 0.03–0.06%	Nostro et al. (2007)
	Oregano	5 μl/ml	Carvacrol	2.5 μl/ml	dos Santos Rodrigues et al. (2017)
	Oregano	575 mg/l	Carvacrol Thymol	175 mg/l 140 mg/l	Lambert et al. (2001)
	Lemongrass	0.54 μl/ml	Citral Geraniol Myrcene	0.62–1.25 μl/mlc 0.62–1.25 μl/ml >17.5 μl/ml	Aiemsaard et al. (2011)
S. aureus (Biofilms)	Oregano	0.25–0.50%	Carvacrol Thymol	0.03–0.12% 0.06–0.12%	Nostro et al. (2007)
	Oregano	10 μl/ml	Carvacrol	5 μl/ml	dos Santos Rodrigues et al. (2017)
S. epidermidis	Oregano	0.06–0.12%	Carvacrol Thymol	0.01–0.03% 0.03–0.06%	Nostro et al. (2007)
S. epidermidis (Biofilms)	Oregano	0.12–0.50%	Carvacrol Thymol	0.03–0.12% 0.03–0.12%	Nostro et al. (2007)
L. monocytogenes	Oregano Thyme	0.05% 0.05%	Carvacrol	0.05%	Desai et al. (2012)
Streptococcus agalactiae	Lemongrass	0.27–0.54 μl/ml	Citral Geraniol Myrcene	0.31–0.62 μl/ml 0.31 μl/ml >17.5 μl/ml	Aiemsaard et al. (2011)
Gram-negative bacteria
E. coli	Thyme	1.60 mg/ml	Carvacrol Thymol	0.20 mg/ml 0.20 mg/ml	Vidács et al., (2018)
	Cinnamon	0.40 mg/ml	CINd	0.20 mg/ml
	Cinnamon	250 μg/ml	CINd	500 μg/ml	Chang et al. (2001)
	Lemongrass	0.54–1.09 μl/ml	Citral Geraniol Myrcene	1.25–2.5 μl/ml 1.25–2.5 μl/ml >17.5 μl/ml	Aiemsaard et al. (2011)
S. Typhimurium	Oregano Thyme	0.05–0.10% 0.05–0.10%	Carvacrol	0.02%	Soni et al. (2013)
P. aeruginosa	Oregano	1648 mg/l	Carvacrol Thymol	450 mg/l 385 mg/l	Lambert et al. (2001)
	Cinnamon	250 μg/ml	CINd	1000 μg/ml	Chang et al. (2001)
K. pneumoniae	Cinnamon	500 μg/ml	CINd	1000 μg/ml	Chang et al. (2001)
B. cereus	Lemongrass	0.13 μl/ml	Citral Geraniol Myrcene	0.15 μl/ml 0.31 μl/ml >17.5 μl/ml	Aiemsaard et al. (2011)
Fungi
C. albicans	C. nardus	64 μg/ml	Citronellal	512 μg/ml	Trindade et al. (2015)

^aMIC: Minimum Inhibitory Concentration.

^bMIC values were determined in a range as they were tested on several strains.

^cMIC values were determined in a range as the experiments were done in triplicates.

^dCIN: Cinnamaldehyde.