<OL> <LI> Develop methodology for enhanced speed for rti-PCR detection of low numbers of V.vulnificus and V. parahaemolyticus in shellfish <LI> Determine the variables involved in the surface transfer of L. monocytogenes from processing surfaces to seafood <LI> Assess the degree of destruction of V. parahaemolyticus on fish tissue treated with lactic and ellagic acids <LI> Determination of the extent of growth and toxin production of B. cereus strains on fish tissue at refrigerator temperatures <LI> Development of nanoemulsions containing eugenol for destruction of V. parahaemolyticus on fish tissue.
NON-TECHNICAL SUMMARY: Documenting the extent of transfer of L. monocytogenes from metal and plastic surfaces onto fish tissue under varying physical parameters will facilitate the development of methods for removal and/or treatment of biofilms on processing equipment for reduction of such transfer.
APPROACH: Research conducted by Robert Levin will include: Preparation of activated carbon coated with bentonite, Removal of PCR inhibitors with activated carbon coated with bentonite from shellfish tissue homogenates, Rti-PCR assays for V. vulnificus and Rti-PCR assays for V. parahaemolyticus. Professor Lynne McLandsborough contribution to this project will include: Quantification of the influence of normal and sheer forces on transfer of Listeria monocytogenes from food processing surfaces to processed foods.This project will investigate the role of shear forces that can contribute to bacterial transfer. Shear forces are forces that are angular to the direction of the transfer. We will determine if there is a linear relationship between the total force (normal force + sheer force) and the number of bacteria transferred. Research will include: Broth studies in the presence of plant extracts plus proline and proline analogs, synergistic effect of lactate and ellagic acid in seafood products, enzyme assays to study mechanism of action. Studies by Professor Ronald Labbe will be directed at growth of toxigenic Bacillus cereus in seafood. Various seafood items will be obtained from retail sources. Seafood consumed raw, e.g., shellfish, and sushi components will be targeted in particular. The concentration of each enterotoxin in seafood homogenates will be determined using commercial assay kits. Growth and toxin production will be assessed. This competitive exclusion work will also be employed with vegetative cell experiments described above. Professor Jochen Weiss research will consist of Inhibition of Vibrio parahaemolyticus by Antimicrobial Nanoemulsions in Model Microbiological and Model Seafood Systems, Preparation, characterization and stability testing of nanoemulsions. Stability of the emulsions will be evaluated over time by measuring size and turbidity of the system over time. Environmental conditions to be tested include pH (4-7) and temperature (4-37C). Also under this portion of the study is antimicrobial efficacy of nanoemulsions in model microbiological systems and seafood.