Sample and sampling area Present study was carried out within June 2012 and November 2012 using 10 export quality frozen shrimp samples. Samples were collected randomly from a shrimp processing industry of Cox’s Bazar and transported immediately to the Microbiology Laboratory of the Stamford University Bangladesh in icebox maintaining the temperature of zero -four oC. Each sample was processed through the blending of 10 g sample (head, body, tail separately) in 90 ml peptone water following serial dilutions up to 10-6 (Cappuccino and Sherman,1996). Isolation and identification of pathogenic microorganisms from shrimp sample: Total viable bacterial & fungal load estimation0.1 ml of each sample was spread onto nutrient agar (NA) following incubation for 12 -24 hours at 37 oC in order to enumerate total viable bacteria(TVB). For fungal estimation, 0.1 ml of each sample was spread onto Sabouraud’s Dextrose Agar (SDA)medium and the plates were incubated at 25 oC for 24 - 48 hours.Isolation of Salmonella spp., Shigella spp., and Vibrio spp.From the total homogenized samples, one ml of sample was transferred to 9 ml of selenite cysteine broth and alkaline peptone water (10-1 dilution) for the enrichment of Salmonella and Vibrio spp., respectively, which were then incubated at 37 oC for six hours. One ml of enriched broth was subjected to 10-fold serial dilution up to 10-6. 0.1ml of the sample was spread onto Salmonella Shigella(SS) agar and Thiosulphate Citrate Bile Salt Sucrose(TCBS) agar plates, following incubation at 37 oC for 24 hours. Isolation of Escherichia coli and Klebsiella spp.0.1 ml of sample was spread onto MacConkey agar medium and was incubated at 37 oC for 24 hours. Plates were examined and the existence of E. Coli was further confirmed by streaking the Eosin-Methylene Blue (EMB) agar for the appearance of bluish-black colony with green metallic sheen after incubation at the above condition. Isolation of Staphylococcus spp., Pseudomonasspp., and Listeria spp.For the isolation of Staphylococcus spp., Pseudomonas spp. and Listeria spp., 0.1 ml of diluted sample was spread on the surface of Mannitol Salt Agar (MSA), Pseudomonas agar and Listeria identification media consecutively, and all plates were incubated at 37 oC for 24 hours. Biochemical identification of bacterial isolate All the suspected isolates were biochemically examined to identify the significant characteristic of bacteria according to the standard methods(Cappuccino and Sherman, 1996; Alfrad, 2007). Determination of antimicrobial susceptibility of the isolates isolates was tested for antibiotic susceptibility on Mueller-Hinton agar (Difco, Detroit, MI) against Trimethoprime/Sulfamethoxazole (25μg), erythromycin (15 μg), amoxicillin (30 μg), Ceftriaxon (30 μg), ciprofloxacin (5 μg), streptomycin (10 μg), Ampicillin (10 μg), tetracycline (30 μg), Chloramphenicol (30 μg), Cefixime (5 μg), Polymixin B (300 units), Kanamycine (30 μg), Vancomycine (30 μg), Gentamycine (10 μg), Nalidixic acid (30 μg), Azythromycine (15 μg) and penicillin G (10 μg) by modified Kirby-Bauer method (Bauer et al.,1966; Munshi et al., 2012). After 24 hours of incubation, plates were examined and the diameters of the zones of inhibition were measured and interpreted as susceptible, intermediate and resistant (Ferraroet al., 2001). Determination of the antibacterial activity of the shrimp: The investigation of the antibacterial activity of the shrimp samples was performed by using agar well diffusion method (Jagessar et al., 2008; Rahman etal., 2012) and also by spot test. In the agar well diffusion method, blend of a different part of the shrimp was used directly on the MHA for the antimicrobial activity against Pseudomonas spp, Listeria spp, Aeromonas spp, Vibrio spp, Salmonella spp, Klebsiella spp, Staphylococcus aureus and E. coli along with positive control (antibiotic disc) and negative control (normal saline). For Aeromonas spp., Listeria spp., Salmonella spp., Klebsiella spp., E. coli, ciprofloxacin (5 μg) was used as a positive control, while for Staphylococcus spp. and Vibrio spp.,trimethoprim-sulphamethoxazole (25 μg) and tetracycline (30 μg) were used as positive controls, respectively. Spot test was performed by dropping blend of different part of shrimp at different concentrations (10, 20, 40 and 100 μl) on MHA andwere allowed to dry off.