title: Inactivation of Salmonella in organic soil by cinnamaldehyde, eugenol, Ecotrol, and Sporan.
abstract: Salmonella can survive in soil for months to years; consequently, soil can be a preharvest source of contamination of produce. Elimination of Salmonella with natural products and processes such as essential oils is important to prevent infection among consumers. Essential oils (distilled extract from plants) have been mainly evaluated in liquid medium and foods in which minimum inhibitory concentration is determined. However, there are no reports describing the impact of essential oils in soil, especially organic soil. We evaluated essential oils for controlling Salmonella enterica serovars in organic soil. Two essential oils (cinnamaldehyde and eugenol), two bio-pesticides (Ecotrol and Sporan), and an organic acid (20% acetic acid) at 0.5%, 1.0%, 1.5%, and 2.0% were mixed with organic sandy soil and inoculated with six different serovars of S. enterica separately. Soils were incubated at room temperature, and samples obtained at 1, 7, and 28 days were enumerated to determine survival. The bactericidal effect of cinnamaldehyde was evident at 0.5%, 1.0%, 1.5%, and 2.0% and during all times of incubation. Overall, Salmonella Negev was the most sensitive strain to oils resulting in significant reductions compared with other strains. Increases in oil concentration resulted in further reduction of Salmonella with all oils used in the study. Up to six log reductions in Salmonella serovars Typhimurium, Negev, and Newport were found after 1 day when cinnamaldehyde, Ecotrol, eugenol, Sporan, or acetic acid was used at 2% level. This study shows the potential use of essential oils to effectively reduce Salmonella populations in soil. The significant reduction of Salmonella could greatly reduce potential contamination of fresh organic produce inadvertently contaminated by soil.
authors.affiliation: Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, USA.
authors.forename: Nadine
authors.initials: N
authors.lastname: Yossa
authors.forename: Jitendra
authors.initials: J
authors.lastname: Patel
authors.forename: Patricia
authors.initials: P
authors.lastname: Millner
authors.forename: Martin
authors.initials: M
authors.lastname: Lo
mesh_terms: D019342:Acetic Acid / Q000008:administration & dosage / Q000494:pharmacology; D000171:Acrolein / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D005054:Eugenol / Q000008:administration & dosage / Q000494:pharmacology; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000517:prevention & control; D050296:Microbial Viability; D009822:Oils, Volatile / Q000008:administration & dosage / Q000494:pharmacology*; D058871:Organic Agriculture / Q000379:methods*; D019779:Salmonella enterica / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D012988:Soil Microbiology; D013045:Species Specificity; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D009822:Oils, Volatile; D005054:Eugenol; D000171:Acrolein; D019342:Acetic Acid; C012843:cinnamaldehyde