Sea Grant Program:
Mississippi‑Alabama Sea Grant Consortium
Title:
Assessment of supercritical CO2 inactivation of oysters associated
bacteria
Start Date: 02/01/08
Duration: 1
year
Project Leader: Hamann, Mark
T.
Affiliation: The University of
Mississippi
Sea Grant Funds (2 years):
$14,996
Matching Funds: $9,134
Keywords:
Seafood, oysters, pasteurization, supercritical CO2, bacteria
Objectives:
To evaluate the effect of SCF CO2 on
cultures of the most critical contaminants commonly isolated from oysters
(Vibrio vulnificus, Vibrio parahaemolyticus) and determine the
proper conditions (temperature, pressure and time) to achieve the optimum
bacterial inactivation in whole oysters after exposure to SCF CO2.
Methodology:
Culture of Vibrio vulnificus and
Vibrio parahaemolyticus will be treated with SFC CO2 at different
temperatures, pressures, and exposure times. The quantification of Vibrio
vulnificus will be completed on TSBS agar and specific media: CC agar for
V. vulnificus and TCBS for V. parahaemolyticus. Optimization
of the SFC CO2 conditions for whole oysters will be achieved by design and
analysis experiments at different temperatures, pressures, and exposure times
using orthogonal design. Microbial analysis of whole oysters will be conducted
following the Bacteriological Analytical Manual (FDA, May 2004) and The
Laboratory Procedure for the Examination of Seawater and Shellfish (American
Public Health Association, 1985).
Rationale:
Seafood products carrying pathogenic
organisms are dangerous when consumed raw and in large quantity. Of these
products, oysters are of greatest concern and have been shown to be responsible
for the largest number of outbreaks in infectious diseases related to the
consumption of seafood products by a significant margin. The development
of milder techniques for pasteurization or inactivation will not only help
extending the shelf life of these products but will also significantly reduce
the transmission of seafood borne infectious diseases. The use of dense
phase carbon dioxide (DPCD) has generated interest in this regard, and has been
applied to a few popular beverages and food products. The unique physical
properties of SCF CO2 allow quick penetration of tissues producing an
antibacterial and enzyme deactivating effect. Our preliminary data revealed the
ability of SCF CO2 to significantly reduce the population of bacteria in whole
oysters.
For More Information Contact: the
MASGC Research Coordinator, Loretta Leist (Loretta.leist@usm.edu).
Please reference the project number
R/AT-8-PD.
(Annual
Report)
