**Fertilization of ponds**

92 Salmonella – A Dangerous Foodborne Pathogen

*Salmonella* is a member of the Enterobacteriaceace, Gram negative, motile, with peritrichous flagella and nonsporeforming rods (the rods are typically 0.7-1.5 μm x 2.5 μm in size). *Salmonella* is a facultatively anaerobic (can grow with or without oxygen) catalase positive and oxidase negative bacteria. However, *Salmonella* is not included in the group of organisms referred to as coliforms (Huss & Gram, 2003; Adams & Moss, 2005; Erkmen, 2007; Lawley et al., 2008). These mesophilic organisms are distrubuted geographically all over the world, but principally occurring in the gastrointestinal tracts of mammals, reptiles, birds, and insects and environments polluted with human or animal excreta (Huss, 1994, Huss & Gram, 2003; Saeed & Naji 2007). Survival in water depends on many parameters such as biological (interaction with other bacteria) and physical factors (temperature). More than 2,500 different types of *Salmonella* exist, some of which cause illness in both animals and people. Some types cause illness in animals but not in people. The various forms of *Salmonella* that can infect people are referred to as serotypes, which are very closely related microorganisms that share certain structural features. Some serotypes are only present in certain parts of the world (Brands, 2006). For over 100 years *Salmonella* have been known to cause illness. The bacterium was first isolated from pigs suffering hog cholera by an American scientist, Dr. Daniel Elmer Salmon, in 1885 (Bremer

**3. Sources of** *Salmonella* **contamination in fish and fishery products** 

*Staphylococcus aureus*, *Clostridium perfringens*, *Salmonella* spp.) (Lyhs 2009).

**Animals (domestic animals, frogs, rodents, birds, insects, reptiles, etc.)** 

Aquatic environments are the major reservoirs of *Salmonella*. Therefore, fishery products have been recognized as a major carrier of food-borne pathogens (Kamat et al., 2005;

Pathogenic bacteria associated with fish and fishery product can be categorised into three general groups: (1) bacteria (indigenous bacteria) that belong to the natural microora of sh (*Clostridium botulinum*, pathogenic *Vibrio* spp., *Aeromonas hydrophila*); (2) enteric bacteria (nonindigenous bacteria) that are present due to fecal contamination (*Salmonella* spp., *Shigella* spp., pathogenic *Escherichia coli*, *Staphylococcus aureus*); and (3) bacterial contamination during processing, storage or preparation for consumption (*Bacillus cereus*, *Listeria monocytogenes*,

Information from literature indicates that fresh fish, fish meal, oysters, farmed and imported frozen shrimp and froglegs can carry *Salmonella* sp., particularly if they are caught in areas contaminated with faecal pollution (prior to harvest and during harvest) or processed, packed, stored, distributed under unsanitary conditions and consumed raw or slightly

During rainfall events, increased run off of organic matter into ponds may occur and can

A variety of animal waste has been shown to be potential sources of *Salmonella*. Animal waste can be introduced directly through bird droppings or frogs living in ponds or

cooked (Kumar et al., 2003; Kamat et al., 2005, Mol et al., 2010; Norhana et al., 2010). There are some pathways of contamination of aquaculture systems with *Salmonella.*

**2. Description of** *Salmonella* 

et al., 2003).

Upadhyay et al., 2010).

**Non-point water run-off** 

indirectly through runoff.

contaminate the aquaculture system.

In some aquaculture systems animal manures are used in ponds to stimulate the production of algae. The use of non-composted manures can lead to production systems being contaminated with *Salmonella*.
