COOPERATIVE RESEARCH NEWS
CATFISH SAFETY INSPECTION PROGRAM
By Dr. Gulnihal Ozbay, Project Director
Mr. Balaji Kubandra Babu, Research Associate
Seafood is one of the most relished culinary delicacies in the world. The consumption of seafood has increased manifold in the last decade. However, the production of seafood in the U.S. has decreased by about 20% in the last 10 years, whereas the value of seafood imported from Vietnam has increased 5 fold in the same time frame.
Catfish ranks number one among the top ten seafoods consumed in the U.S. As of 2007, the per capita consumption of catfish was 0.87 pounds. There is an increase in demand for both domestic and imported catfish in the U.S. In 2005, the catfish imported from Vietnam were recalled due to the concerns of antibiotic residues. A similar recall was issued for catfish imported from China in 2007. In the wake of recent recalls of some of the imported fish, the United States Department of Agriculture (USDA) has beefed up the scrutiny of imported and domestic seafood. The most recent recall involved the mackerel imported from Vietnam for concerns of Clostridium botulinum contamination.
The use of unapproved antimicrobial drugs in the raising of fish can cause acute and chronic health effects in people. An acute response could be an allergy, but chronic effects may take a long time to develop and cancer is considered a chronic long-term effect. The catfish grown in ponds may also have heavy metals in them due to bioaccumulation.
The short-term goal of this Cooperative Research project in the College of Agriculture and Related Sciences is to determine the presence of antimicrobial drugs, heavy metals and food borne pathogens in both domestic and imported catfish fillets. The long-term goal is to establish a nationally recognized Catfish Research and Education Center, which couples research with extension programs.
The catfish fillets purchased from retail outlets in Delaware, Maryland, Virginia, and Washington, DC are tested for the presence of Salmonella species and generic Escherichia coli. The microbial floras in the samples are also quantified using Aerobic Plate Count (APC) and Psychrotrophic plate count (PPC).The catfish fillets are tested for the presence of pathogens as per the protocol set forth in the Microbiological Laboratory Guidebook (MLG).
CATFISH FILLETS LINED UP FOR TESTING
AEROBIC PLATE COUNT (APC) IN CATFISH SAMPLES
PLATING OF INOCULUM ON PETRIDISHES
ANTIMICROBIAL DRUG TESTING
The presence of antimicrobial drugs like Chloramphenicol, Malachite Green and Gentian Violet in the catfish fillets are detected using ELISA (Enzyme Linked ImmunoSorbent Assay). The testing is done as per the protocol set forth by the USDA-FSIS, Office of Public Health Science CLG.
READING ELISA PLATES IN A BIOTEK® ELISA READER
EXTRACTION OF SAMPLES FOR CHLORAMPHENICOL DETECTION
PHOTOGRAPH OF AN ELISA PLATE SCREENING
Heavy metals testing
As of January 2011, the installation of the Atomic Absorption Spectrophotometer (AAS) is completed. The AAS aids in the detection of heavy metals like Cadmium (Cd), Lead (Pb), Mercury (Hg) and Arsenic (As) in the catfish fillets. The detection of heavy metals in catfish fillets began in January 2011 and will continue through September 2011.
The Catfish project team includes Dr. Gulnihal Ozbay as Project Director; Dr. Brigid McCrea and Dr. Dennis McIntosh as Co-Project Directors; Mr. Balaji Kubandra Babu as Research Associate; Ms. Huldah Haynes as Research Technician; and undergraduate student interns Adeyimika Adepoju, Pamela Stampul, Eunice Handy, Brandon Bruce, Yesenia Rosado, and Venessa Richards. This project is funded by the USDA-FSIS Seafood Inspection Program and the Catfish Inspection Laboratory is established with the same USDA-FSIS funding.
Picture 'AAS' is Atomic Absorption Spectrometer 600.
'FIMS' is Flow Injection Mercury System
Note: This project is funded by USDA-FSIS Catfish Inspection Program and allowed DSU to establish a laboratory for inspecting both domestic and imported catfish for microbiological and chemical contaminants. The funding is also provided to the Cooperative Extension Program to establish a catfish processing laboratory and community outreach and education.