This study examined the antimicrobial effect of blueberry (Vaccinium corymbosum L.) extracts obtained from four cultivars (Elliott, Darrow, Bluecrop, and Duke) on the growth of Listeria monocytogenes and Salmonella Enteritidis. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the extracts against L. monocytogenes and S. Enteritidis in tryptic soy broth were determined. Concentrations of total phenolic compounds and four individual phenolic (chlorogenic acid, ellagic acid, quercetin, and quercetin-3-galactoside) in the extracts were determined using Folin-Ciocalteau method and HPLC analysis, respectively. All four extracts at 112.5–900 mg/mL exhibited a dose-dependent growth-inhibitory effect against L. monocytogenes and S. Enteritidis. L. monocytogenes was significantly more sensitive to the antimicrobial effect of the extracts than S. Enteritidis. Phenolic compounds in the extracts such as chlorogenic acid, quercetin, ellagic acid, and quercetin-3-galactoside were the active antimicrobial compounds in the blueberry extracts. The results of this study suggest that blueberry extract or extract-derived components may be used to control pathogenic microorganisms. More studies on the use of blueberry as a natural antimicrobial in food products are warranted.
