title: Growth interactions and antilisterial effects of the bacteriocinogenic Lactococcus lactis subsp. cremoris M104 and Enterococcus faecium KE82 strains in thermized milk in the presence or absence of a commercial starter culture.
abstract: Traditional Greek cheeses are often produced from thermized milk (TM) with the use of commercial starter cultures (CSCs), which may not inhibit growth of Listeria monocytogenes completely. Therefore, this study evaluated the behavior of an artificial L. monocytogenes contamination in commercially TM (63 °C; 30 s) inoculated with a CSC plus Lactococcus lactis subsp. lactis M104 and/or Enterococcus faecium KE82, two indigenous strains producing nisin A and enterocin A and B, respectively. Inoculation treatments included TM with the CSC only, and TM without the CSC but with strain M104 alone, or combined with strain KE82. All treatments were incubated at 37 °C for 6 h followed by 66 h at 18 °C. L. monocytogenes grew by 0.66-1.24 log cfu/ml at 37 °C, whereas its further growth at 18 °C was retarded, suppressed, or accompanied by different inactivation rates, depending on each TM treatment. Strain M104 caused the greatest inactivation, whereas the CSC per se was the least effective treatment. Strain KE82 assisted the CSC in controlling pathogen growth at 37 °C, whereas both reduced the nisin A-mediated antilisterial activity of strain M104. Overall, the most 'balanced' treatment against L. monocytogenes was CSC+M104+KE82. Hence, this starter/co-starter combination may be utilized in traditional Greek cheese technologies.
authors.affiliation: Dairy Research Institute, General Directorate of Agricultural Research, Hellenic Agricultural Organization DEMETER, Katsikas, 45221, Ioannina, Greece.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Lianou
authors.affiliation: Dairy Research Institute, General Directorate of Agricultural Research, Hellenic Agricultural Organization DEMETER, Katsikas, 45221, Ioannina, Greece.
authors.forename: Athanasia
authors.initials: A
authors.lastname: Kakouri
authors.affiliation: Dairy Research Institute, General Directorate of Agricultural Research, Hellenic Agricultural Organization DEMETER, Katsikas, 45221, Ioannina, Greece.
authors.forename: Eleni C
authors.initials: EC
authors.lastname: Pappa
authors.affiliation: Dairy Research Institute, General Directorate of Agricultural Research, Hellenic Agricultural Organization DEMETER, Katsikas, 45221, Ioannina, Greece. Electronic address: jsam@otenet.gr.
authors.forename: John
authors.initials: J
authors.lastname: Samelis
mesh_terms: D000818:Animals; D058491:Bacterial Load; D001430:Bacteriocins / Q000096:biosynthesis* / Q000494:pharmacology; D002611:Cheese / Q000382:microbiology; D016984:Enterococcus faecium / Q000254:growth & development* / Q000502:physiology; D005506:Food Contamination / Q000517:prevention & control; D005519:Food Preservation; D006041:Goats; D006115:Greece; D006358:Hot Temperature; D013294:Lactococcus lactis / Q000254:growth & development* / Q000502:physiology; D008089:Listeria monocytogenes / Q000254:growth & development* / Q000502:physiology; D056265:Microbial Interactions; D008892:Milk / Q000737:chemistry / Q000382:microbiology*; D009561:Nisin / Q000096:biosynthesis
chemical_list: D001430:Bacteriocins; D009561:Nisin; C102526:nisin A
keywords: Enterococcus faecium KE82; Lactococcus lactis subsp. cremoris M104; Listeria monocytogenes; Thermized milk