Inhibition of Brochothrix thermosphacta and sensory improvement of tropical peeled cooked shrimp by Lactococcus piscium CNCM I-4031.
OBJECTIVE
To investigate the antimicrobial spectrum of Lactococcus piscium CNCM I-4031 and its protective effect in cooked and peeled shrimp against Brochothrix thermosphacta.


RESULTS
Sixteen pathogenic and spoiling bacteria were inhibited in Elliker, but not in shrimp juice agar plates. In shrimp packed under modified atmosphere and stored at 8 degrees C, B. thermosphacta (10(3) CFU g(-1)) was inhibited by 4.1 log CFU g(-1) when co-inoculated with L. piscium (10(6) CFU g(-1)). Brochothrix thermosphacta spoiled the product after 11 days, with the emission of strong butter/caramel off-odours. In co-culture with L. piscium, sensory shelf-life was extended by at least 10 days. The inhibition was partially explained by a drop in pH from 6.6 to 5.6. The physicochemical composition of shrimp and shrimp juice was established to identify the inhibition mechanisms involved.


CONCLUSIONS
Lactococcus piscium CNCM I-4031 has a wide antimicrobial spectrum. The strain inhibits B. thermosphacta in shrimp and significantly prolongs sensory shelf-life.


CONCLUSIONS
Lactococcus piscium CNCM I-4031 is shown to be a promising agent for improving shrimp quality and may be tested against pathogens and in other food matrices. Knowledge of the physicochemical composition of shrimp and shrimp juice will allow the development of a chemically defined model medium for determining the inhibition mechanisms involved.
Laboratoire de Science et Technologie de la Biomasse Marine, Ifremer, Nantes, France.
P A
PA
Fall
F
F
Leroi
M
M
Cardinal
F
F
Chevalier
M F
MF
Pilet
D000898:Antibiosis; D001419:Bacteria / Q000254:growth & development*; D018920:Coculture Techniques; D003470:Culture Media; D005506:Food Contamination / Q000517:prevention & control*; D005511:Food Handling; D005516:Food Microbiology; D017045:Lactococcus / Q000254:growth & development*; D012758:Shellfish / Q000032:analysis / Q000382:microbiology*
D003470:Culture Media