effect of lemon, orange and bergamot essential oils and their components on the survival of Campylobacter jejuni, Escherichia coli O157, Listeria monocytogenes, Bacillus cereus and Staphylococcus aureus in vitro and in food systems

• Published in: Journal of applied microbiology Vol. 101; no. 6; pp. 1232 - 1240
• Main Authors: Fisher, K, Phillips, C.A
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.12.2006; Blackwell Publishing Ltd; Blackwell Science
• Subjects: Animals; Bacillus cereus; Bacillus cereus - drug effects; Bacteria - drug effects; Biological and medical sciences; Brassica; Brassica - microbiology; Campylobacter jejuni; Campylobacter jejuni - drug effects; Chickens; Chromatography, Gas; Citrus; Citrus bergamia; Citrus limon; Citrus sinensis; Escherichia coli; Escherichia coli O157 - drug effects; essential oils; Food Microbiology; Food Preservation - methods; Fundamental and applied biological sciences. Psychology; Gram negative; Gram positive; Humans; Listeria monocytogenes; Listeria monocytogenes - drug effects; Meat - microbiology; Microbial Sensitivity Tests; Microbiology; Oils, Volatile - pharmacology; Plant Oils; Staphylococcus aureus; Staphylococcus aureus - drug effects; vapours; Costa Rica, Limon; Applied microbiology; Campylobacteraceae; Escherichia coli; Campylobacter coli; Bacillaceae; vapours; Bacillus cereus; Bacillales; Gram positive bacteria; Bacteria; Micrococcales; Micrococcaceae; Chemical composition; Essential oil; Staphylococcus aureus; Enterobacteriaceae; Gram negative bacteria; Listeria monocytogenes; Foodstuff; Gram negative; In vitro; Survival; Campylobacter jejuni; essential oils; Gram positive
• ISSN: 1364-5072; 1365-2672
• DOI: 10.1111/j.1365-2672.2006.03035.x

To investigate the effectiveness of oils and vapours of lemon (Citrus limon), sweet orange (Citrus sinensis) and bergamot (Citrus bergamia) and their components against a number of common foodborne pathogens. The disc diffusion method was used to screen the oils and vapours against Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, Escherichia coli O157 and Campylobacter jejuni. The survival of each species, demonstrated to be susceptible in the in vitro studies, was tested on cabbage leaf for 60 s by direct contact and on chicken skin for 10 min by direct contact and 24 h by vapour. The results indicate that bergamot was the most inhibitory essential oil (EO) and citral and linalool mimicked its effect (P > 0·001). Citral and linalool vapours produced 6 log reductions in L. monocytogenes, Staph. aureus and B. cereus populations on cabbage leaf after 8-10 h exposure but bergamot vapour exposure, while producing a similar reduction in L. monocytogenes and B. cereus populations, had no effect on Staph. aureus. Bergamot was the most effective of the oils tested and linalool the most effective anti-bacterial component. Gram-positive bacteria were more susceptible than Gram-negative bacteria in vitro, although Camp. jejuni and E. coli O157 were inhibited by bergamot and linalool oils and by linalool vapour. All bacteria tested were less susceptible in food systems than in vitro. Of the Gram-positive bacteria tested Staph. aureus was the least susceptible to both the oils and the components tested. Results suggest the possibility that citrus EOs, particularly bergamot, could be used as a way of combating the growth of common causes of food poisoning.