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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 #361103
Research Project: Characterization and Mitigation of Bacterial Pathogens in the Fresh Produce Production and Processing Continuum

Location: Environmental Microbial & Food Safety Laboratory

Title: Antimicrobial effects of natural fruit extracts against Salmonella on cucumbers

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

Submitted to: International Association for Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: 3/19/2019
Publication Date: 7/21/2019
Citation: Byun, S., Chen, C., Yin, H., Patel, J.R. 2019. Antimicrobial effects of natural fruit extracts against Salmonella on cucumbers. International Association for Food Protection. 2:194.

Interpretive Summary:

Technical Abstract: Introduction: Salmonellosis outbreaks linked to the consumption of contaminated cucumbers have highlighted the need to develop effective interventions for improving microbial safety of cucumbers. Purpose: The efficacy of fruit extracts namely lemon, yuzu, grapefruit (naringin), and grape (resveratrol) for reducing Salmonella on cucumbers was investigated. Methods: Fresh Persian cucumbers (N=128) purchased from local retailer were submerged in 70% ethanol for 1 min to remove surface wax. Each cucumber was marked with two 1 cm x 5 cm areas and spot-inoculated with 20 µl of 9 log CFU/ml of Salmonella cocktail (S. Newport, Poona, and Typhimurium) to obtain 5 log CFU/cm2 on cucumbers. After air-drying for 2 h, each inoculated area was sprayed with 1 ml treatment solution, including controls (water, 15% ethanol, and water adjusted to pH 3.0), 10% lemon, 10% yuzu, 1% naringin, or 1% resveratrol. After treatment, cucumbers were stored at 10°C or 22°C for 7 days. On days 0, 2, 5, and 7, each marked area was swabbed with cotton applicator; swab was pummeled for 2 min in 10 ml of buffered peptone water, and then plated on XLT4 agars. Results: There was no significantly difference in Salmonella populations among the controls (P>0.05). At 22°C, Salmonella populations recovered from naringin and resveratrol-treated cucumbers were 3.5 and 3.0 log CFU/cm2, respectively, compared to 5.0 log CFU/cm2 Salmonella from control on day 2 (P<0.05). Fruit extracts exerted higher antimicrobial activity against Salmonella on cucumbers stored at 10°C; lemon and yuzu extracts reduced Salmonella populations by ~ 2.5 log CFU/cm2 on day 7 as compared to control (P<0.05). The antibacterial effect of these extracts was marginal at 22°C. Significance: The results of this study reveal that fruit extracts could potentially be used to kill Salmonella on cucumbers. The storage temperature may influence the effectiveness of these extracts on cucumbers.