Fishery Technology 2005, Vol. 42(2) pp : 209 - 216 Level of Escherichia coli in Seafood in Domestic Trade and their Antibiotic Resistance Pattern A . Surendraraj, Nirmala Thampuran* and P.K. Surendran Central Institute of Fisheries Technology, Cochin - 682 029, India Bacteriological quality of fish/shellfish sold in retail outlets in and around Cochin, India was studied. The TPC for the different samples varied from 5.5 to 8.5 log cfu/g. The total Enterobacteriaceae count varied from 2.5 to 6.5 log cfu/g. The lactose fermenters count and total coliforms count varied from 2 to 6 log cfu/g. Seafood samples had Escherichia coli count ranging from 2 to 5.5 log cfu/g. The faecal streptococci count was between 2 to 5 log cfu/ g The majority of the E.coli isolates showed a Multiple Antibiotic Resistance (MAR) index of more than 0.5, suggesting that they may be from high risk sources. Only a low percentage of samples were acceptable for human consumption as per Indian Standards for market sold fresh fishes. Higher count of microbial indicator organisms confirms possible presence of bacteria of public health significance and demands stringent improvement in handling and sanitary practices in the markets. Keywords: Bacte riological quality, fish/shellfish, retail markets, E.coli, MAR index. Microbial safety is one of the public health issues associated with seafood con- sumption. Contamination due to unhygienic handling entails the risk of spreading the bacterial, viral or pathogenic agents of communicable enteric diseases. It has been established that quality of fish sold in domestic market is poor compared to that of export trade and they were mostly contami- nated with , pathogenic organisms (Nambiar & Iyer, 1990). The bacteriological quality of freshly landed and retail level seafood sold in different parts of the country has been reported by previous workers (Comar et al, 1979; Lakshmanan et al, 1984; Iyer et al, 1986; Pradeep & Lakshmanaperumalsamy 1986; Varma et al, 1988; Nambiar & Iyer 1990). And these studies have established that a sizable portion ofthe seafood available inthe market for consumption is not meeting the quality criteria prescribed by Indian Standards. The occurrence of Multiple Antibiotic Resistance (MAR) among the enteric bacte- rial species could be a problem associated with transfer of resistance to other organisms of human/veterinary significance (Toranzo et al, 1983). Parveen et al. (1997) proposed MAR index for differentiating the sources of pollution. This study is intended to estimate whether global impacts of recent years have improved the quality of seafood of retail level and to assess the risk of prevalence of antibiotic resistance among the E.coli isolates from retail sold seafood samples. Materials and Methods Seafood viz. finfishes, Indian oil sardine (Sardinella longiceps), Indian mackerel (Rastrelliger kanagurta), Pink perch (Nemipterus japonicus) and Pearlspot (Etroplus suratensis), Shrimp (Metapenaeus dobsonii), and Black clam both fresh and boiled (Villorita cyprinoides) from various markets in and around Cochin, were collected. Five market places were selected for study over a period * Correspondingauthor.