Identification of Gram Negative Bacteria in Different Ready-to-Eat Foods Vended in Different Institutional Premises Situated in Dhaka City

Abstract

Ready to eat foods vended on the streets are foods and beverages that are prepared and sold for immediate consumption by vendors on the street or other public places. These types of foods are an affordable source of nourishment for the students, low income workers and others. The objective of this study was to identify presence of gram negative bacteria in different ready-to eat foods vended in different institutional premises situated in Dhaka City. From the premises, 30 food samples were collected and tested to find out the presence of suspected enteric bacteria E.coli, Vibrio, Klebsiella, Salmonella and Shigella spcies. Five different agar media were used to observe the growth of the microorganisms. Later several different biochemical tests were performed to find out the presence of bacteria in the samples. Among 30 samples, 17 (56.6%) samples were observed to be contaminated by different bacteria. Among 17, after biochemical tests were performed, 7 (23.3%) samples were observed to be contaminated with the suspected microorganisms. Among 7 (23.3%) samples, 3 (10%) samples were suspected to contain Klebsiella spp., 2(6.66%) samples were suspected to contain E.coli and 2 (6.66%) samples were suspected to contain Vibrio spp. We have also performed colony counting of additional 6 ready to eat food samples by standard method. The samples were Nargis kabab, Chola, Laddu, Boroi achar, Alur chop and Tikia. Out of 6 samples, Colony Forming Units (CFUs) have been observed and maximum concentrated colonies were found in Laddu, Tikia, Nargis kabab and Chola. All these enteric bacteria can be the potential cause of foodborne illness and so they pose as a great hazard to the students. Therefore, providing appropriate education and training to the street vendors has become an important necessity to ensure good public health.