Avijit Banik
Department of Microbiology, Primeasia University, HBR Tower, 9 Banani C/A, Dhaka-1213, Bangladesh
Maruf Abony
Department of Microbiology, Primeasia University, HBR Tower, 9 Banani C/A, Dhaka-1213, Bangladesh
Suvamoy Datta
Department of Microbiology, Primeasia University, HBR Tower, 9 Banani C/A, Dhaka-1213, Bangladesh
Syeda Tasneem Towhid
Department of Microbiology, Jagannath University, Dhaka-1100, Bangladesh.
Street foods, Enteric pathogens, Multi-drug resistance, Food poisoning, Dhaka
Dhaka City, Bangladesh
Food Safety and Security
Food, Bacteria
Sample Collection and Enrichment Procedure: A total of 90 street food samples were collected in triplicates (fried salty, spicy boiled, sweet sugary solids, fruits, juice and rice cookies) from different vendors from 10 different areas (Banani, Mohakhali, Agargaon, Baridhara, Nilkhet, Uttara, Rampura, Farmgate, Dhanmondi & Newmarket) around Dhaka city between November 2015 to March 2017. All samples were collected in presterilized zip-lock bags (165 mm x 150 mm x 0.55 mm) and freshly-extracted juice samples (100 mL each) were collected in sterile bottles, transported to the laboratory in ice-boxes (4°C). All samples were transported to the Centre for Excellence Laboratory (CEL), Department of Microbiology, Primeasia University, Dhaka-1213, Bangladesh within 2 hours for processing and further assessment. Sample Preparation: Ten grams of solid food sample was added to 90 mL of normal saline, homogenized and prepared for spread plate technique. For juice samples, 10 mL of samples were properly diluted in 90 mL sterile normal saline (0.85% NaCl). One mL of each homogenate from samples was added in decimal dilutions up to 10-6 in 0.85% NaCl solution. Plate Count agar (Oxoid, Hampshire, England) was used to determine Total Viable Bacterial Count (TVBC). Salmonella-Shigella agar (SSA), Mannitol Salt agar (MSA) and Eosine Methylene Blue agar (EMB) (all from Oxoid, Hampshire, England) were used to identify enteric pathogens Salmonella-Shigella, S. aureus, and E. coli respectively. 2.3 Isolation and Identification of Specific Pathogens The pre-enrichment technique was used to detect delicate food pathogens E. coli, Salmonella spp, S. aureus, Vibrio spp., and Campylobacter spp. Twenty- five gm of each sample was homogenized in 225 mL of buffered peptone water (Oxoid Ltd, Hampshire, England) and incubated at 37°C for 20 to 24 hours, followed by culture in the specific medium as detailed in the next sub-sections. Presumptive identification of Salmonella spp: One mL of pre-enrichment culture was mixed with 10 mL of Henja Tetrathionate Broth (HiMedia Laboratories, Mumbai, India) and was incubated at 37°C for 20 to 24 hours. The culture broths were subsequently streaked onto Salmonella-Shigella agar (SSA) (Oxoid Ltd, Hampshire, England) and Bismuth Sulphite agar (BSA) (HiMedia Laboratories, Mumbai, India) to identify Salmonella spp. Presumptive identification of Vibrio spp: One mL of the homogenized food sample was mixed with 9 mL of alkaline peptone Broth (Oxoid Ltd, Hampshire, England), incubated at 37°C for 20 to 24 hours at alkaline level pH (8-9) spread onto Thiosulfate Citrate bile salts sucrose (TCBS) agar media (Oxoid Ltd, Hampshire, England) and incubated for 24 hours at 37°C to identify Vibrio spp. Statistical Analysis: After conducting biochemical analysis of isolates, results were analyzed in STATA 14.1 statistical program for cluster analysis by multivariate analysis inward linkages.
Journal of Advances in Microbiology, 13(1): 1-13, 2018; Article no. JAMB.44163, ISSN: 2456-7116
Journal