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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Environmental Microbial & Food Safety Laboratory » Research » Publications at this Location » Publication #362971
Research Project: Characterization and Mitigation of Bacterial Pathogens in the Fresh Produce Production and Processing Continuum

Location: Environmental Microbial & Food Safety Laboratory

Title: Biocontrol of foodborne pathogens on strawberries with lactic acid bacteria

Author
item BOOMER, ASHLEY - US Department Of Agriculture (USDA)
item YIN, HSIN-BAI - US Department Of Agriculture (USDA)
item CHEN, CHI-HUNG - US Department Of Agriculture (USDA)
item BYUN, SUYEUN - US Department Of Agriculture (USDA)
item Patel, Jitu

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: 4/5/2019
Publication Date: 4/24/2019
Citation: Boomer, A., Yin, H., Chen, C., Byun, S., Patel, J.R. 2019. Biocontrol of foodborne pathogens on strawberries with lactic acid bacteria. BARC Poster Day. 6:21.

Interpretive Summary:

Technical Abstract: Small fruits such as strawberries have been increasingly implicated in outbreaks of foodborne illnesses. Salmonella enterica and Listeria monocytogenes are important foodborne pathogenic bacteria that may contaminate and survive on strawberries leading to the potential public health concern. The objective of this study was to investigate the efficacy of canine-feces origin lactic acid bacteria (LAB) including Lactobacillus plantarum and Pediococcus pentosaceus for controlling Salmonella enterica and Listeria monocytogenes on fresh strawberries at the post-harvest level. Strawberries (N=288) purchased from the local grocery store were sorted for identical size and dip-inoculated in phosphate buffered saline (PBS) containing ~ 9.0 log CFU/ml of Salmonella Newport, Salmonella Tennessee, Salmonella Thompson, or Listeria monocytogenes for 2 min, followed by air-drying for 1 h. Pathogen-inoculated strawberries were then divided into three groups: (1) Control (pathogen alone), (2) MRS control (dip in MRS broth), and (3) LAB treatment (dip in a LAB cocktail of L. plantarum and P. pentosaceus). After treatment, strawberries were stored at 4ºC or 10ºC for 7 days. Surviving pathogen and LAB populations on strawberries were determined on 0, 1, 3, and 7 days-post-treatment by spiral plating on selective agars. There was no significant difference in pathogen populations between the control and MRS control (P > 0.05). LAB treatment significantly reduced populations of S. Tennessee, S. Thompson, and S. Newport by 2.8 log, 2.6 log, and 1.5 log CFU/g on day 3 at 4ºC, respectively, as compared to the control. On day 7, recovery of Salmonella was 1.5 log CFU/g on LAB-treated strawberries compared to ~ 3.5 log CFU/g Salmonella recovered from the control samples at both temperatures (P < 0.05). Similarly, LAB treatment significantly decreased Listeria populations by 1.5 log, 2.0 log, and 2.5 log CFU/g as compared to the control on days 1, 3, and 7, respectively, at both 4ºC and 10ºC of the storage (P<0.05). Approximately 7.5 log CFU/g of LAB populations were enumerated throughout the entire study. Results of this study suggest that LAB can potentially be used as biocontrol agents against Salmonella and Listeria monocytogenes contamination on strawberries at the post-harvest level.