Bacterial strains were grown on agar plates at 37C overnight under aerobic conditions and bacterial cells were collected in
10 mL of phosphate buffered saline using a sterile 10 mL loop under a biosafety cabinet. The optical density of the bacterial suspension was adjusted to an absorbance value of 0.10 at 600 nm on a Beckman DU640 spectrophotometer
. A 100 mL aliquot of the bacterial suspension was added to the wells of a 6-well culture plate containing either 5 mL of skim milk, blueberry juice alone, blueberry juice supplemented with 5% glucose or 50% blueberry juice and 50% skim milk mixture and incubated for 24, 48 and 72 h at 37C. For determination of time required for inhibition of growth, 100 mL aliquot of the bacterial suspension was added to the wells of a 6-well culture plate containing either 5 mL of BHI broth , blueberry juice alone, blueberry juice supplemented with 5% glucose or 50% skim milk plus 50% blueberry juice and incubated for 0, 1, 2, 4 or 6 h at 37C. Following incubation, serial dilutions were prepared in PBS and plated on strain-specific agar to measure bacterial growth