Advances in Molecular Tools for the Detection of Food-Borne Pathogens

Fish and shellfish are perhaps one of the earliest recognized food commodities in the history of mankind. Fish, with its high protein content and being the sole source of omega-3 fatty acids, are considered nutritionally rich and generally regarded as healthy foods. Also, aquatic foods are the cheapest sources of proteins for a vast and ever-increasing population worldwide. Apart from these, seafood is the most traded commodity with the annual turnover of over 86 billion U.S. dollars. The increased international trade has resulted in world-wide movement of seafood with the consumer having little or no knowledge of the sources, modes of preservation, or the quality of the food. The increased movements of food, changing eating habits and changing ways of growing, harvesting and preparing foods have raised concerns on the safety all foods including the seafood. The concern is consolidated by the global incidences of seafood-borne outbreaks. In the United States, where a strict record keeping system exists, 1,034 foodborne disease outbreaks have occurred in 2008 in which more than 23,000 people fell ill, and 22 people died (CDC 2011). The prominent foods that caused the outbreaks were poultry (15%), beef (14%), and fish (14%). However, the global incidences of food-borne diseases remain largely unknown but are presumed to be in an increasing trend. The most common pathogenic bacteria responsible for seafood-borne illnesses are Vibrio parahemolyticus, V. cholerae, V. vulnificus, Salmonella, Escherichia coli, Listeria monocytogenes. While Vibrios are natural inhabitants of coastal-marine waters, enterobacteria such as Salmonella and E. coli are introduced via fecal contamination of the environment or secondary contamination of seafood during handling, processing or storage. Apart from bacterial pathogens, a number of enteric viruses and parasites such as trematodes are also involved in significant morbidity and mortality. However, little is known about these infectious agents owing to poor understanding of their etiology, lack of surveillance and absence of proper methods of detection.