Table 4.

Efficacy of combined treatment of essential oils as antibacterial complex.

Components of the EO-Based Antibacterial Complex	Treatment Conditions	Target Microorganisms	Combined Treatment 1	Antibacterial Effects (Log Reduction; Log CFU/g or mL) [combined effect]	Reference
Combination of EOs	37 °C, 24 h	Escherichia coli	CA 100 mg/L + TM 100 mg/L	2.2 [Synergism]	[36,37]
			CA 100 mg/L + CAR 100 mg/L	2.1 [Synergism]
			TM 100 mg/L + CAR 100 mg/L	2.4 [Synergism]
	37 °C, 24 h	Salmonella Typhimurium	CA 50 mg/L + TM 100 mg/L	0.44 [Synergism]	[37]
			CA 50 mg/L + CAR 100 mg/L	0.42 [Synergism]
			TM 100 mg/L + CAR 100 mg/L	0.27 [Synergism]
Medium chain fatty acid	37 °C, 24 h	Escherichia coli O157:H7	capric acid 0.4 mM + RA/CAR/EUG/TM/TC 0.4 mM	>7 [Synergism]	[25]
			caprylic acid 1.0 mM + RA/CAR/EUG/TM/TC 1.0 mM
			lauric acid 0.5 mM + RA/CAR/TM 1.0 mM
	40 °C, 10 min	Cronobacter sakazakii	caprylic acid 20 mM + VNL 30 mM	>7 [Synergism]	[62]
	40 °C, 5 min	Salmonella Typhimurium	caprylic acid 20 mM + VNL 30 mM
Organic acid	37 °C, 24 h	Salmonella Typhimurium	lactic acid 0.10% + CAR 200 µL/L	0.37 [Synergism]	[37]
			acetic acid 0.05% + TM 100 mg/L	0.57 [Synergism]
			acetic acid 0.05% + CAR 100 µL/L	0.15 [Synergism]
Caprylic acid + citric acid	3 °C, 10 d	Listeria monocytogenes	0.5% caprylic acid + 0.1% citric acid + 0.2% oregano oil	<5 [Synergism]	[78]
Citrus fruit extracts	22 °C, 5 min	Escherichia coli O157:H7 (Acid-adapted)	calamansi 10% + CAR/TM 2.0 mM	>6.9 [Synergism]	[45]
		Salmonella Typhimurium (Acid-adapted)	calamansi/lemon 10% + CAR/TM 2.0 mM
		Listeria monocytogenes (Acid-adapted)	calamansi/lemon/lime 10% + CAR/TM 2.0 mM
Lauric arginate (LAE)	21 °C, 48 h	Listeria monocytogenes	LAE 375 ppm + cinnamon leaf oil/EUG/TM 3,000 ppm	>4 [Synergism]	[84]
		Escherichia coli O157:H7	LAE 375 ppm + cinnamon leaf oil/EUG 2,500 ppm	>2 log growth 2 [Antagonism]
			LAE 375 ppm + TM 2,000 ppm	>2 log growth 2 [Antagonism]
		Salmonella Enteritidis	LAE 375 ppm + cinnamon leaf oil/EUG 2,500 ppm	>1 log growth 2 [Antagonism]
			LAE 375 ppm + TM 2,000 ppm	>2 log growth 2 [Antagonism]
Nisin	8 °C, 20 min	Listeria monocytogenes	nisin 5.3 µg/mL + CAR 1.3 mmol/L	ca. 3 log reduction [Synergism]	[79]
	8 °C, 30 min	Bacillus cereus	nisin 5.3 µg/mL + CAR 0.7 mmol/L	ca. 3 log reduction [Synergism]
	4 °C, 12 d	Listeria monocytogenes	nisin 1000 IU/g + thyme essential oil 0.6%	4.0 log reduction [Synergism]	[80]
	4 °C, 12 d	Salmonella Enteritidis	nisin 500 IU/g + oregano essential oil 0.9%	ca. 4 log reduction [Synergism]	[82]
	37 °C, 32 h	Escherichia coli O157:H7	nisin 500 IU/g + thyme essential oil 0.6%	ca. 1 log reduction [Synergism]	[81]
EDTA	37 °C, 24 h	Salmonella Typhimurium	EDTA 75 mg/L + TM 100 mg/L	0.7 log reduction [Synergism]	[37]
Sodium chloride	22 °C, 1 min	Escherichia coli O157:H7	sodium chloride 5% + CAR 2.0 mM	7 log reduction [Synergism]	[44]
		Listeria monocytogenes
		Staphylococcus aureus	sodium chloride 10% + CAR 2.0 mM
	22 °C, 1 min	Escherichia coli O157:H7	sodium chloride 3% + TM 2.0 mM	7 log reduction [Synergism]
		Listeria monocytogenes	sodium chloride 10% + TM 1.0 mM
		Staphylococcus aureus	sodium chloride 15% + TM 1.0 mM
Soy sauce	4 °C, 5 min	Escherichia coli O157:H7	soy sauce + TM 0.5 mM	7 log reduction [Synergism]	[30]
	4 °C, 5 min	Listeria monocytogenes	soy sauce + TM 0.5 mM
	4 °C, 10 min	Salmonella Typhimurium	soy sauce + TM 0.5 mM
Teriyaki sauce	4 °C, 7 d	Escherichia coli O157:H7	teriyaki sauce + TM/CAR 0.5%	3.0–3.4 log reduction [Synergism]	[83]
		Listeria monocytogenes
		Salmonella Typhimurium
Biological silver nano particles (bio-AgNPs)	37 °C, 24 h	Methicillin resistant Staphylococcus aureus	bio-AgNP 125 µM + Origanum vulgare oil 0.298 mg/mL	>5 log reduction [Synergism]	[67]
		Escherichia coli	bio-AgNP 31.25 µM + Origanum vulgare oil 0.075 mg/mL	>5 log reduction [Synergism]

¹ Abbreviation of essential oils: cinnamaldehyde (CA), thymol (TM), carvacrol (CAR), β-resorcylic acid (RA), eugenol (EUG), and trans-cinnamaldehyde (TC).