35-10

R. K. KING, Food Science and Technology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 and G. J. Flick, Jr.

Aquaculture has become the fastest growing segment of world agriculture. Recirculating aquaculture offers the greatest potential for success since it is requires limited resources, and is independent of environmental conditions. However, this form of aquaculture presents a potential unacceptable public health risk. With growing concerns for increased antibiotic resistant organisms, controlling pathogenic microorganisms is paramount. Biofilms form on all aquaculture system components, incorporating microflora present in the water. Pathogenic microorganisms are found in this biofilm, causing recurring exposure to disease and the presence of asymptomatic carriers. The project objective is to increase the understanding of pathogen incorporation into biofilms in recirculating aquaculture systems by determining their ability to attach to various materials used in construction of those systems. One mariculture, one hydroponics, and five freshwater aquaculture facilities were sampled, with eight different types of material tested. Pathogenic bacteria were identified using BAM methods and the Becton-Dickinson BBL Crystal ID Kit. Various pathogenic bacteria were identified, including Aeromonas hydrophila, other Aeromonads, Vibrios, Yersinias, and Bacillus cereus. The most significant variation in biofilm pathogens was observed in facility type and not construction material. Some of the microorganisms identified are pathogens for both fish and humans and can be significant in further processed seafoods. Bacillus cereus is a spore-forming bacteria which is thermally resistant, making it difficult to eliminate with normal food processing techniques. Vibrio species were found in the biofilms in both freshwater and saltwater systems. Some Yersinia species, such as Yersinia enterocolitica, are becoming more recognized as food or water-borne pathogens. Whether the presence of these organisms in biofilms could lead to food-borne illness is unclear, but the potential is there. More research on pathogenic organisms in biofilms is required. Because the materials used for facility construction were not significant, increased biosecurity measures leading to pathogen elimination should also be investigated.