University of Surrey

Test tubes in the lab Research in the ATI Dance Research

The antimicrobial efficacy of plant essential oil combinations and interactions with food ingredients.

Gutierrez, J, Barry-Ryan, C and Bourke, P (2008) The antimicrobial efficacy of plant essential oil combinations and interactions with food ingredients. Int J Food Microbiol, 124 (1). pp. 91-97.

Full text not available from this repository.

Abstract

The objective of this study was to evaluate the efficacy of plant essential oils (EOs) in combination and to investigate the effect of food ingredients on their efficacy. The EOs assessed in combination included basil, lemon balm, marjoram, oregano, rosemary, sage and thyme. Combinations of EOs were initially screened against Bacillus cereus, Escherichia coli, Listeria monocytogenes and Pseudomonas aeruginosa using the spot-on-agar test. The influence of varying concentrations of EO combinations on efficacy was also monitored using E. coli. These preliminary studies showed promising results for oregano in combination with basil, thyme or marjoram. The checkerboard method was then used to quantify the efficacy of oregano, marjoram or thyme in combination with the remainder of selected EOs. Fractional inhibitory concentrations (FIC) were calculated and interpreted as synergy, addition, indifference or antagonism. All the oregano combinations showed additive efficacy against B. cereus, and oregano combined with marjoram, thyme or basil also had an additive effect against E. coli and P. aeruginosa. The mixtures of marjoram or thyme also displayed additive effects in combination with basil, rosemary or sage against L. monocytogenes. The effect of food ingredients and pH on the antimicrobial efficacy of oregano and thyme was assessed by monitoring the lag phase and the maximum specific growth rate of L. monocytogenes grown in model media. The model media included potato starch (0, 1, 5 or 10%), beef extract (1.5, 3, 6 or 12%), sunflower oil (0, 1, 5 or 10%) and TSB at pH levels of 4, 5, 6 or 7. The antimicrobial efficacy of EOs was found to be a function of ingredient manipulation. Starch and oils concentrations of 5% and 10% had a negative impact on the EO efficacy. On the contrary, the EOs were more effective at high concentrations of protein, and at pH 5, by comparison with pH 6 or 7. This study suggests that combinations of EOs could minimize application concentrations and consequently reduce any adverse sensory impact in food. However, their application for microbial control might be affected by food composition, therefore, careful selection of EOs appropriate to the sensory and compositional status of the food system is required. This work shows that EOs might be more effective against food-borne pathogens and spoilage bacteria when applied to ready to use foods containing a high protein level at acidic pH, as well as lower levels of fats or carbohydrates.

Item Type: Article
Authors :
NameEmailORCID
Gutierrez, Jj.gutierrez@surrey.ac.ukUNSPECIFIED
Barry-Ryan, CUNSPECIFIEDUNSPECIFIED
Bourke, PUNSPECIFIEDUNSPECIFIED
Date : 10 May 2008
Identification Number : 10.1016/j.ijfoodmicro.2008.02.028
Uncontrolled Keywords : Bacteria, Colony Count, Microbial, Consumer Product Safety, Dose-Response Relationship, Drug, Drug Synergism, Food Contamination, Food Microbiology, Food Preservation, Food Preservatives, Humans, Hydrogen-Ion Concentration, Microbial Sensitivity Tests, Oils, Volatile, Plant Oils
Related URLs :
Depositing User : Symplectic Elements
Date Deposited : 17 May 2017 10:00
Last Modified : 17 May 2017 14:46
URI: http://epubs.surrey.ac.uk/id/eprint/826009

Actions (login required)

View Item View Item

Downloads

Downloads per month over past year


Information about this web site

© The University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
+44 (0)1483 300800