title: Cronobacter sakazakii reduction by blueberry proanthocyanidins.
abstract: Blueberry juice and blueberry polyphenols reportedly have antimicrobial properties against foodborne pathogens, without much currently known on their effects against Cronobacter sakazakii. This study evaluated the antimicrobial effects of blueberry proanthocyanidins (PAC) and commercial blueberry juice (BJ) against two strains of C. sakazakii, ATCC 29004 and 29544. BJ (pH 2.8), blueberry PAC (5 mg/ml) and controls (phosphate buffered saline (PBS), pH 7.2, and malic acid pH 3.0) were mixed with equal volumes of washed overnight cultures of C. sakazakii and incubated for 30 min, 1 h, 3 h and 6 h at 37°C. Reductions of ∼1 and 1.50 log CFU/ml were obtained for strains 29004 and 29544, respectively after 30 min with BJ or blueberry PAC. Both C. sakazakii strains 29004 and 29544 were reduced to undetectable levels from 8.25 ± 0.12 log CFU/ml and 8.48 ± 0.03 log CFU/ml, respectively with BJ (pH 2.8) or blueberry PAC after 1 h, while malic acid (pH 3.0) showed ∼1.3 log CFU/ml reduction for both strains. Scanning electron microscopy studies showed differences in cell membrane morphology with clumping and formation of blebs of the treated strains compared to untreated controls. These results warrant further in vivo studies with blueberry bioactives to determine potential for preventing and treating C. sakazakii infections.
authors.affiliation: Department of Food Science and Technology, University of Tennessee, 2600 River Drive, Knoxville, TN 37996-4591, United States.
authors.forename: Snehal S
authors.initials: SS
authors.lastname: Joshi
authors.affiliation: Marucci Center for Blueberry and Cranberry Research, Rutgers, State University of New Jersey, Chatsworth, NJ, United States.
authors.forename: Amy B
authors.initials: AB
authors.lastname: Howell
authors.affiliation: Department of Food Science and Technology, University of Tennessee, 2600 River Drive, Knoxville, TN 37996-4591, United States. Electronic address: ddsouza@utk.edu.
authors.forename: Doris H
authors.initials: DH
authors.lastname: D'Souza
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D029798:Blueberry Plants / Q000737:chemistry*; D044083:Cronobacter sakazakii / Q000187:drug effects* / Q000254:growth & development; D005638:Fruit / Q000737:chemistry; D010936:Plant Extracts / Q000494:pharmacology*; D044945:Proanthocyanidins / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D044945:Proanthocyanidins
keywords: Blueberry proanthocyanidins; Cronobacter sakazakii; Reduction