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<OL> <LI>To isolate and identify the predominant microbiota in fresh fish (Mahi-mahi, King mackerel, Spanish mackerel, Atlantic bluefish) from the mid-Atlantic region including specific spoilage organisms and toxigenic histamine-producing bacteria. <LI> To determine the bacterial, chemical and sensory effects of bulk and retail packaging fresh fish stored in air and reduced-oxygen (vacuum and modified atmosphere) at ideal (<2C) and slightly abusive (10C) temperatures. <LI> To validate the safety of the novel bulk/retail packaging system through inoculated pack studies with known histamine-producing bacteria in fresh fish held at ideal (<2C) and slightly abusive (10C) temperatures. <LI> To transfer the knowledge gained to the domestic seafood industry through a series of public workshops, publications, information flyers and web-based seafood science and technology programs.
Non-Technical Summary: Vacuum and modified-atmosphere packaging are two reduced-oxygen techniques that are effective in reducing growth of aerobic spoilage organisms and increasing shelf-life of refrigerated foods. The techniques are popular in Europe and becoming increasing popular in the United States for packaging of fresh fish. Unfortunately, there is limited information known about the influence of this packaging technology on inhibition of scombrotoxin formation by Gram negative bacteria associated with spoilage in fresh fish. Our purpose is to better understand the influence of reduced-oxygen packaging on inhibition of scombrotoxin formation by Gram-negative bacteria associated with fresh fish. We will define the minimum temperatures for growth and biogenic amine production of toxigenic histamine-forming bacteria. And, we will identify practical temperatures that would minimize the levels of biogenic amines in all steps of the production chain and in the final product. <P> Approach: This project builds upon our previous studies on histamine-forming bacteria in fresh yellowfin tuna and mahi-mahi and the recent studies on retail MAP of tuna loins/steaks. Our hypothesis is that fresh fish stored in bulk MAP intended to control scombrotoxin (histamine) formation and then subsequently packed in case-ready retail MAP intended to control growth and toxin production by Clostridium botulinum type E at refrigeration temperatures will greatly improve the safety and increase the quality and shelf life of fresh fish for sale in domestic US markets. Fresh fish will be obtained from North Carolina licensed fishermen or dealers who receive fish directly from commercial fishing vessels. Mahi-mahi (Coryphaena hippurus), mackerel (Scomberomorus cavalla and S. scombrus), and bluefish (Pomatomus saltatrix) will be packed in ice on receipt for transport to the NCSU Seafood Laboratory. Fish will be sampled during the spring and fall to determine seasonal differences in meat composition that may impact microbiota and quality. We will sample mahi-mahi beginning in year one, mackerels in year two and bluefish in year three of the project which is expected to take five years to complete.