Effect of the bacteriocin carnocin CP5 and of the producing strain Carnobacterium piscicola CP5 on the viability of Listeria monocytogenes ATCC 15313 in salt solution, broth and skimmed milk, at various incubation temperatures.
Carnobacterium piscicola CP5, isolated from French mould-ripened soft-cheese, produced a bacteriocin named carnocin CP5 in a wide range of incubation temperatures, from 4 degrees C to 30 degrees C. The ability of a crude bacteriocin, of a partially-purified form, and of the producer strain to inhibit growth of Listeria monocytogenes ATCC 15313 was examined in salt solution, broth and skimmed milk between 4 degrees C and 30 degrees C. When carnocin CP5 was added to a L. monocytogenes ATCC 15313 culture, an adsorption on cells and a bactericidal effect with a cell lysis occurred. At 30 degrees C, with carnocin CP5 or with C. piscicola CP5, a transitory bactericidal effect was observed. Subsequent experiments at 4 degrees C, 7 degrees C or 15 degrees C, showed a more prolonged bactericidal effect. Thus at 7 degrees C, partially-purified carnocin CP5 reduced an initial population level of L. monocytogenes of 10(3) cfu/ml to non-detectable level within 7 days. However, in some cases, with extended incubation, the carnocin CP5 effect was no longer visible, the L. monocytogenes population grew again. This phenomenon was probably due to the presence of a sub-population of bacteriocin-resistant variants.
Mathieu
F
F
Laboratoire de Microbiologie Industrielle et Alimentaire, ENSAIA-INPL, Vandoeuvre les Nancy, France.
Michel
M
M
Lebrihi
A
A
Lefebvre
G
G
D000818:Animals; D001430:Bacteriocins / Q000096:biosynthesis / Q000494:pharmacology*; D002611:Cheese / Q000382:microbiology*; D015169:Colony Count, Microbial; D003470:Culture Media; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D008089:Listeria monocytogenes / Q000187:drug effects / Q000254:growth & development*; D008892:Milk / Q000382:microbiology
D001430:Bacteriocins; D003470:Culture Media; C089245:carnocin CP5