title: Evaluation of corn oil as an additive in the pre-enrichment step to increase recovery of Salmonella enterica from oregano.
abstract: Phenolic compounds associated with essential oils of spices and herbs possess a variety of antioxidant and antimicrobial properties that interfere with Salmonella detection from fresh and dried products. Finding a compound to neutralize the effect of these antimicrobial compounds, while allowing Salmonella growth during pre-enrichment, is a crucial step in both traditional pathogen isolation and molecular detection from these foods. This study evaluated the effectiveness of corn oil as a component of the pre-enrichment broth to counteract antimicrobial compounds properties and increase the recovery of Salmonella from spices. Oregano samples artificially contaminated with Salmonella enterica were pre-enriched in modified Buffered Peptone Water (mBPW) supplemented with and without 2% (vol/vol) corn oil respectively. Samples were incubated overnight at 37 °C. The results showed that recovery of Salmonella from oregano samples was increased by ≥50% when pre-enriched with corn oil. Serovars were confirmed using a PCR serotyping method. In addition, shot-gun metagenomics analyses demonstrated bacterial diversity and the effect of corn oil on the relative prevalence of Salmonella in the oregano samples. Modifying pre-enrichment broths with corn oil improved the detection and isolation of Salmonella from oregano, and may provide an alternative method for pathogen detection in dried food matrices such as spices.
authors.affiliation: U.S. Food and Drug Administration, Laurel, MD, 20708, USA. Electronic address: junia.jean-gillesbeaubrun@fda.hhs.gov.
authors.forename: Junia
authors.initials: J
authors.lastname: Jean-Gilles Beaubrun
authors.affiliation: U.S. Food and Drug Administration, Laurel, MD, 20708, USA; UMCP JIFSAN Program, 5201 Paint Branch Pkwy Patapsco Building Suite 2134, University of Maryland, College Park, 20742, USA.
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Flamer
authors.affiliation: U.S. Food and Drug Administration, Laurel, MD, 20708, USA; Oak Ridge Institute for Science and Technology, Oak Ridge, TN, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Addy
authors.affiliation: U.S. Food and Drug Administration, Laurel, MD, 20708, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Ewing
authors.affiliation: U.S. Food and Drug Administration, Laurel, MD, 20708, USA.
authors.forename: Gopal
authors.initials: G
authors.lastname: Gopinath
authors.affiliation: U.S. Food and Drug Administration, Laurel, MD, 20708, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Jarvis
authors.affiliation: U.S. Food and Drug Administration, Laurel, MD, 20708, USA; Oak Ridge Institute for Science and Technology, Oak Ridge, TN, USA.
authors.forename: Chris
authors.initials: C
authors.lastname: Grim
authors.affiliation: U.S. Food and Drug Administration, Laurel, MD, 20708, USA.
authors.forename: Darcy E
authors.initials: DE
authors.lastname: Hanes
mesh_terms: D003314:Corn Oil / Q000494:pharmacology*; D003470:Culture Media / Q000378:metabolism; D031341:Origanum / Q000382:microbiology*; D019779:Salmonella enterica / Q000187:drug effects / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D003470:Culture Media; D003314:Corn Oil
keywords: Additives; Corn oil; Molecular serotyping; Montevideo; Oregano; Salmonella spp.; Shot-gun metagenomics