Factors affecting production of an antilisterial bacteriocin by Carnobacterium piscicola strain A9b in laboratory media and model fish systems.
OBJECTIVE
To investigate factors influencing bacteriocin production and bacteriocin stability of the bioprotective culture Carnobacterium piscicola strain A9b.


RESULTS
Maximum activity was obtained in MRS7 broth (MRS adjusted to pH 7.2), with or without glucose. No bacteriocin was produced in APT broth when a low inoculum level (0.001%) was used. In contrast, inoculum level did not influence bacteriocin production in BHI and MRS7 without glucose. Bacteriocin production in APT was induced by the presence of an extracellular compound present in the sterile, filtered, cell-free supernatant fluid of a stationary-phase culture. Increasing concentrations of NaCl (2-7%) reduced bacteriocin production and maximum cell density of C. piscicola A9b when grown in cooked fish juice at 4 degrees C.


CONCLUSIONS
Media composition, inoculum level and sodium chloride concentration affected production.


CONCLUSIONS
The influence of NaCl on bacteriocin production may negate the inhibitory effect of C. piscicola A9b against Listeria monocytogenes in salty foods.
Himelbloom
B
B
University of Alaska Fairbanks, Fishery Industrial Technology Center, AK, USA.
Nilsson
L
L
Gram
L
L
D000362:Agar; D000818:Animals; D001430:Bacteriocins / Q000096:biosynthesis* / Q000494:pharmacology*; D003470:Culture Media / Q000378:metabolism; D005399:Fishes; D005516:Food Microbiology; D005519:Food Preservation; D005947:Glucose / Q000378:metabolism; D006093:Gram-Positive Asporogenous Rods / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008087:Listeria / Q000187:drug effects* / Q000378:metabolism; D023421:Models, Animal; D012965:Sodium Chloride / Q000494:pharmacology
D001430:Bacteriocins; D003470:Culture Media; D012965:Sodium Chloride; D000362:Agar; D005947:Glucose