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ARS Home » Northeast Area » Kearneysville, West Virginia » Appalachian Fruit Research Laboratory » Research » Publications at this Location » Publication #361094
Research Project: Production Management Research for Berry Crops (BRIDGE PROJECT)

Location: Appalachian Fruit Research Laboratory

Title: Microbial quality of blueberries for the fresh market

Author
item QUANSAH, JOYCELYN - University Of Georgia
item GAZULA, HIMABINDU - University Of Georgia
item HOLLAND, RENEE - University Of Georgia
item SCHERM, HARALD - University Of Georgia
item LI, CHANGYING - University Of Georgia
item Takeda, Fumiomi
item CHEN, JINRU - University Of Georgia

Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2018
Publication Date: 1/4/2019
Citation: Quansah, J.K., Gazula, H., Holland, R., Scherm, H., Li, C., Takeda, F., Chen, J. 2019. Microbial quality of blueberries for the fresh market. Food Control. 100:92-96. https://doi.org/10.1016/j.foodcont.2018.12.034.
DOI: https://doi.org/10.1016/j.foodcont.2018.12.034

Interpretive Summary: In this study, microbial quality of 124 fresh blueberry samples collected from six packing houses at the start of the day, mid-day, and the end of the day was determined. Eleven berry samples from three packing houses tested positive for fecal coliforms and one sample tested positive for enterococci. Berry samples collected at the end of the day had lower microbial counts than those collected in the morning. The study suggested exposure of blueberries to packing line does not lead to significant reduction in microbial counts. Thorough washing of retail blueberries before consumption is encouraged.

Technical Abstract: Harvested blueberries are sorted in packinghouses to remove pre-mature fruits and plant debris, packaged in polyethylene clamshells, and cooled in refrigeration facilities before being shipped to the fresh markets. This study determined the microbial quality of fresh blueberries collected from berry-packinghouses. Unpacked and packed blueberries (n=124) were collected in duplicate at the beginning of the day, lunchtime, and the end of the day from six different packinghouses in Georgia in the summer of 2015 and 2017. Collected berries were rinsed or homogenized in 0.1 M phosphate buffered saline and appropriate dilutions were inoculated on tryptic soy agar, MacConkey agar, Enterococcus agar and potato-dextrose agar. Resulting microbial colonies were enumerated, and presumptive fecal coliforms and enterococci confirmed. Eleven berry samples from three packinghouses tested positive for fecal coliforms and one sample tested positive for enterococci. Mean total aerobic counts, total yeast and mold count, and total coliform counts of the berries were 3.89, 4.42 and 1.42 log CFU/g, respectively. Sampling time had significant influence (P=0.05) on the recovery of all three groups of microorganisms. On average, berry samples collected at the end of the day had the lowest microbial count. Homogenization of berries recovered significantly higher numbers of yeast and mold, and total coliform cells than rinsing. In general, packing process had no significant influence (P>0.05) on recovered microbial count; however, unpacked berries had numerically higher aerobic counts, and yeast and mold counts than packed berries. Study suggests that sorting of blueberries before packing for the fresh market does not lead to significant reduction in microbial count.