title: Short communication: Combined antimicrobial activity of reuterin and diacetyl against foodborne pathogens.
abstract: Reuterin (β-hydroxypropionialdehyde) is a broad-spectrum antimicrobial substance produced by some strains of Lactobacillus reuteri during anaerobic fermentation of glycerol. Some of these strains are able to survive and produce reuterin in cheese and yogurt when added as adjuncts to the starter. Similarly, in fermented dairy foods, other inhibitory compounds such as lactic acid and diacetyl are produced during fermentation. In this work, we studied the combined effect of reuterin and diacetyl under different pH conditions against Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes. Results from agar spot assays showed that the antimicrobial activity of reuterin-producing strains against the gram-negative bacteria tested was enhanced as the concentration of diacetyl increased to 50 mg/kg, and was higher under acidic conditions (pH 5.0) for the 3 pathogenic strains. The combination of reuterin and diacetyl had an additive effect against L. monocytogenes only at diacetyl concentrations of 50 mg/kg and pH 5.0. In addition, growth kinetics studies showed that the combination of 1 activity unit (AU)/mL of reuterin with 100mg/kg diacetyl increased the lag time of the 3 pathogens. In milk, synergistic antimicrobial activity was observed with the combination of 1 AU/mL reuterin and 50 or 100 mg/kg of diacetyl on the gram-negative strains tested, and with 1 AU/mL reuterin and 100 mg/kg of diacetyl on L. monocytogenes. The greatest inhibition of the 3 pathogens was achieved in acidified milk at pH 5.0 with reuterin (1 AU/mL) and diacetyl (100 mg/kg). Based on these results, the combination of reuterin and diacetyl in acidified dairy products could be a promising strategy to control food pathogens in these products.
authors.affiliation: Dpto. de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de La Coruña Km 7, 28040 Madrid, Spain. Electronic address: langa.susana@inia.es.
authors.forename: S
authors.initials: S
authors.lastname: Langa
authors.affiliation: Dpto. de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de La Coruña Km 7, 28040 Madrid, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Martín-Cabrejas
authors.affiliation: Dpto. de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de La Coruña Km 7, 28040 Madrid, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Montiel
authors.affiliation: Dpto. de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de La Coruña Km 7, 28040 Madrid, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Landete
authors.affiliation: Dpto. de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de La Coruña Km 7, 28040 Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Medina
authors.affiliation: Dpto. de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de La Coruña Km 7, 28040 Madrid, Spain.
authors.forename: J L
authors.initials: JL
authors.lastname: Arqués
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000302:isolation & purification / Q000494:pharmacology*; D002611:Cheese / Q000382:microbiology; D003931:Diacetyl / Q000302:isolation & purification / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D019453:Escherichia coli O157 / Q000187:drug effects / Q000254:growth & development; D005260:Female; D005285:Fermentation; D005506:Food Contamination / Q000517:prevention & control*; D005516:Food Microbiology; D005985:Glyceraldehyde / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D052200:Limosilactobacillus reuteri / Q000737:chemistry*; D008089:Listeria monocytogenes / Q000187:drug effects / Q000254:growth & development; D008892:Milk / Q000382:microbiology*; D011407:Propane / Q000302:isolation & purification / Q000494:pharmacology*; D012477:Salmonella enteritidis / Q000187:drug effects / Q000254:growth & development
chemical_list: D000890:Anti-Infective Agents; C047158:3-hydroxypropionaldehyde; D005985:Glyceraldehyde; D003931:Diacetyl; D011407:Propane
keywords: bioprotection; diacetyl; foodborne pathogen; reuterin