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United States Department of Agriculture

Agricultural Research Service

Research Project: MICROBIAL ECOLOGY AND SAFETY OF FRESH ON-FARM ORGANICALLY GROWN PRODUCE Title: Antimicrobial properties of essential oils against Salmonella in organic soil

Authors
item Patel, Jitu
item Yossa, Nadine - U-MARYLAND
item Millner, Patricia
item Yo, Martin - U-MARYLAND

Submitted to: Annual Meeting of the Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: February 10, 2009
Publication Date: June 6, 2009
Citation: Patel, J.R., Yossa, N., Millner, P.D., Yo, M. 2009. Antimicrobial properties of essential oils against Salmonella in organic soil. IFT 2009 Annual Meeting Book of Abstracts. Paper No. 123-31. p. 153.

Technical Abstract: Soil is one of the important sources of preharvest contamination of produce with pathogens. Demand for natural pesticides such as essential oils for organic farming practices has increased. Antimicrobial activity of essential oils in vitro has been documented. The antimicrobial activity of essential oils was evaluated against Salmonella in soil. Three essential oils (Cinnamanaldehyde, ecotrol, eugenol) and vinegar at 0.5 and 2 percent, prepared in sterile distilled water containing 5 percent Tween 20 were transferred in organic sandy soil. Soil (10 g) in bags was inoculated individually with Salmonella cultures (S. Thompson, S. Braenderup, S. Negev, S. Newport, S. Tennessee, S. Typhimurium) to have initial bacterial population ca. 6 log CFU/g soil. Soil samples without any oil served as a control. After 1, 7, and 28 days at room temperature (22 deg C), soil samples were appropriately diluted in PBS and spiral plated on XLT4 agar plates. Following incubation at 37 deg C for up to 48 h, presumptive salmonella colonies were counted. Vinegar and eugenol at 0.5 percent level significantly reduced Salmonella in soil irrespective of Salmonella strain. Salmonella populations in soil reduced by up to 5 log CFU/ml after 28 days of incubation using vinegar or eugenol. The bactericidal effect of Cinnamanaldehyde was not evident either at 0.5 or 2 percent level. Overall, S. negev was the most sensitive strain to oils resulting in significant reduction compared to those with other Salmonella strains. Increase in oil concentration resulted in further reduction of Salmonella with all oils used in the study. Three log reductions in Salmonella were found after 1 day when ecotrol or eugenol was used at 2 percent level. This study shows potential use of oils to effectively reduce Salmonella populations in soil. The significant reduction of Salmonella could greatly reduce potential contamination to organic produce from soil.

Last Modified: 12/22/2014
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