title: Antimicrobial activity of nisin, reuterin, and the lactoperoxidase system on Listeria monocytogenes and Staphylococcus aureus in cuajada, a semisolid dairy product manufactured in Spain.
abstract: The inhibitory activity of nisin (N), reuterin (R), and the lactoperoxidase system (LPS), added individually or in combination, against Listeria monocytogenes and Staphylococcus aureus was investigated in "cuajada" (curdled milk), a semisolid dairy product manufactured in Spain. Cuajada was manufactured from UHT skim milk separately inoculated with L. monocytogenes and Staph. aureus, each at approximately 4 log cfu/mL, and held under conditions of temperature abuse (10 degrees C). On d 3, a synergistic bactericidal activity was observed for the combinations of biopreservatives assayed, with L. monocytogenes counts of only 0.30 log cfu/mL in cuajada made with N + R + LPS vs. 8.31 log cfu/mL in control cuajada. After 12 d, L. monocytogenes could not be detected in cuajada made with added N + LPS or N + R + LPS. Staphylococcus aureus was more resistant than L. monocytogenes to biopreservatives added individually. On d 3, the synergistic effect of the 3 biopreservatives against Staph. aureus resulted in counts of 3.03 log cfu/mL in cuajada made with N + R + LPS vs. 6.40 in control cuajada. After 12 d, Staph. aureus counts were 2.61 log cfu/mL in cuajada made with N + R + LPS, whereas they ranged from 6.11 to 7.70 log cfu/mL in control cuajada and in cuajada made with other combinations of biopreservatives. The most pronounced decrease in pathogen counts was achieved by the triple combination N + R + LPS, which acted synergistically on the inactivation of L. monocytogenes and Staph. aureus in cuajada over 12 d at 10 degrees C. The treatment combining these 3 natural biopreservatives at low concentrations, within the hurdle concept of food preservation, might be a useful tool to control the growth of pathogenic microorganisms in nonacidified dairy products.
authors: Departamento de Tecnología de Alimentos, INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria), Carretera de La Coruña km 7, 28040-Madrid, Spain.
authors: J L
authors: JL
authors: Arqués
authors: E
authors: E
authors: Rodríguez
authors: M
authors: M
authors: Nuñez
authors: M
authors: M
authors: Medina
mesh_terms: D000447:Aldehydes / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003611:Dairy Products / Q000382:microbiology*; D005516:Food Microbiology; D005520:Food Preservatives / Q000494:pharmacology*; D005985:Glyceraldehyde / Q000031:analogs & derivatives / Q000494:pharmacology; D007784:Lactoperoxidase / Q000494:pharmacology; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000254:growth & development*; D008088:Listeriosis / Q000517:prevention & control; D009561:Nisin / Q000494:pharmacology; D011407:Propane / Q000494:pharmacology; D013030:Spain; D013202:Staphylococcal Food Poisoning / Q000517:prevention & control; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development*
chemical_list: D000447:Aldehydes; D000900:Anti-Bacterial Agents; D005520:Food Preservatives; D009561:Nisin; C047158:3-hydroxypropionaldehyde; D005985:Glyceraldehyde; D007784:Lactoperoxidase; D011407:Propane