PASTEURIZED BLUEBERRY (VACCINIUM CORYMBOSUM) JUICE INHIBITS GROWTH OF BACTERIAL PATHOGENS IN MILK BUT ALLOWS SURVIVAL OF PROBIOTIC BACTERIA

ABSTRACT Compounds found in berries exhibit a wide range of effects including antimicrobial activities. In this study, the antimicrobial properties of blueberry juice against the foodborne pathogens Salmonella Typhimurium, Campylobacter jejuni, Listeria monocytogenes and enterohemorrhagic Escherichia coli O157:H7 were investigated. Inhibition was measured in 100% blueberry juice or a 1:1 (v/v) mixture of milk and blueberry juice with growth in 100% milk used as a control. The growth of all four pathogens was reduced below the detection level (100 cfu/mL) by blueberry juice, and reduced by 4–7 log cfu/mL in a mixture of milk and blueberry juice. The effects of blueberry juice on probiotic bacteria Lactobacillus bulgaricus and Bifidibacterium bifidis were also investigated. The growth was less in a 1:1 (v/v) mixture of blueberry juice and skim milk as compared with milk alone, but these probiotic organisms were able to survive and grow. These data demonstrate the potential of blueberry juice for use as an all-natural antimicrobial. PRACTICAL APPLICATIONS Foodborne pathogens sicken millions in the U.S.A. each year. The research reported here indicates that juice from blueberries can inhibit the growth of these foodborne bacteria. In addition, the blueberry juice did not substantially inhibit the growth of beneficial bacteria such as those found in yogurt.