29G-2 |
Antimicrobial activity exhibited by bacteria isolated from selected US honey samples |
H. LEE, M. A. Mundo, J. J. Churey, O. I. Padilla-Zakour, and R. W. Worobo. Food Science & Technology, Cornell Univ., New York State Agricultural Experiment Station, 630 W. North St., Geneva, NY 14456-1371 The antimicrobial properties of honey have been known for thousands of years. The antimicrobial activity has been attributed to hydrogen peroxide, osmolarity, acidity, aromatic acids and phenolic compounds. An additional unidentified antimicrobial compound exists that is only found in select honey samples. The antimicrobial compounds contained in honey may have potential to inhibit foodborne pathogens and food spoilage microorganisms. The objective of this study was to investigate the nature of the various antimicrobial compounds found in honey and to examine the honey microflora for the production of antimicrobial substances. Five US honey samples from different flora sources and geographical locations were supplied by the National Honey Board (Tarweed, Blackberry, Cottonseed, Buckwheat and Rabbitbush). The samples were tested for the presence of antimicrobial activity using the well diffusion method. The bacterial microflora of each honey was isolated by plating onto non-selective media (Tryptic Soy Agar) and incubating at 30°C for 48 hours. These isolates were screened for production of antimicrobial compounds against Bacillus subtilis ATCC 6633, Bacillus cereus F4552, Listeria monocytogenes F2-586 1053 and Byssochlamys fulva H25 using the deferred inhibition assay. A high incidence of antimicrobial inhibition was observed with the bacterial isolates from all five varieties of honey. A range of 44% to 89% of the bacterial isolates from all 5 honeys showed strong antifungal activity while 30% of bacterial isolates from the 5 honey sources exhibited antibacterial activity against Bacillus cereus and Bacillus subtilis. L. monocytogenes F2-586 1053 showed higher overall rates of sensitivity, ranging from 11 to 66% of the bacterial isolates from the honey samples. The additional antimicrobial activity exhibited by select honey samples could be due to the production of antimicrobial substances by the bacteria present in honey and therefore could have great potential for food safety and food quality applications.
Session 29G, Food Microbiology: General
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