Date palm fruits available in intact packets were collected from retail shops of Dhaka city, Bangladesh. The cultivar's name, weight, and name of the country were recorded. The samples were brought to the Department of Botany, Jahangirnagar University (JU), Savar, Dhaka, for further analysis. A part of the study was performed in the Department of Biochemistry and Molecular Biology, JU. One g of each fruit sample was suspended in 9 ml sterile saline (0.9% NaCl) and mixed well to get 10 fold dilution of the fruit sample. After thoroughly mixing, decimal serial dilution was performed to enumerate the microbial load in the fruit samples. One hundred microliters of the suspension from the serially diluted samples were spread onto the nutrient agar (NA) medium and potato dextrose agar (PDA) medium to enumerate the total aerobic plate count (APC) and total yeast and mold count (YMC), respectively. The NA plates were incubated at 37°C for 24 hrs and PDA plates were incubated at room temperature for 5 days. The APC and YMC were expressed as colony-forming units per g (cfu/g) of fruit. Twenty-two morphologically dissimilar colonies were randomly selected from NA plates and streaked on the NA plate to obtain a pure culture. The streaked plates were incubated at 37°C for 24 hrs. The well-isolated single colony was selected and subjected to further purification through repeated plating by streaking method. The colony characteristics of the bacteria that grew onto the NA plates were recorded. The selected isolates (DPB1-DPB22) were subjected to morphological, cultural, and biochemical studies. At first, Gram staining, oxidase test, and catalase test were performed. The API 20E (Biomerieux, France) test strips were used following the manufacturer's instructions to identify the Gram-negative bacterial isolates. The following tests were performed by using API 20E strips: test for β-galactosidase enzyme by hydrolysis of the substrate o- nitrophenyl-β-D-galactopyranoside (ONPG), decarboxylation of the amino acid arginine by arginine dihydrolase (ADH), decarboxylations of the amino acid lysine by lysine decarboxylase (LDC), decarboxylations of the amino acid ornithine by ornithine decarboxylase (ODC), utilization of citrate as the only carbon source (CIT), production of hydrogen sulfide (H2S), test for the urease (URE), detection of the tryptophan deaminase (TDA), Indole test (IND) for production of indole from tryptophan by the enzyme tryptophanase, Voges-Proskauer (VP) test for the detection of acetoin produced by fermentation of glucose by bacteria utilizing the butylene glycol pathway, test for the production of the gelatinase which liquefies gelatin (GEL), fermentation of glucose (GLU), fermentation of mannose (MAN), fermentation of inositol (INO), fermentation of sorbitol (SOR), fermentation of rhamnose (RHA), fermentation of sucrose (SAC), fermentation of melibiose (MEL), fermentation of amygdalin (AMY), and the fermentation of arabinose (ARA). Other isolates were identified based on morphological, biochemical, and cultural characteristics (Holt et al. 1994, Cappuccino and Sherman 1996, Brooks et al. 2007). To validate the identity of the bacteria obtained by morphological and biochemical tests, one isolate (DPB1) was subjected to molecular identification based on 16S rRNA gene sequencing. The genomic DNA was isolated as described previously (Kabir and Tasmim 2019). For amplification of 16S rRNA gene sequence universal primer pairs, 27F (5´-GAGTTGATCC TGGCTCA-3´) and 1492R (5´-GAAAGGAGGTGATCCAGC-3´) were used. Amplification was carried out in an automatic thermocycler (Astec, Japan). Initial denaturation was done at 95°C for four minutes followed by 30 thermal cyclings consisting of denaturation at 95°C for 30 s, annealing at 49°C for 30 s, and extension at 72°C for one min and 30 s. A final extension at 72 °C for five min was done. The PCR product was loaded onto 0.8% agarose gel containing ethidium bromide solution and DNA ladder (Promega, USA) was used as a DNA size marker. Electrophoresis was done at a constant voltage of 100 V for 1.5 hr in a horizontal electrophoresis system and then visualized under a UV-transilluminator. The PCR product was excised from the gel and purified with the Wizard PCR SV gel and PCR clean-up system (Promega, USA). The sequences of PCR products were determined in both directions with an ABI 3700 Genetic Analyzer (1st Base Laboratory, Malaysia). The sequence was retrieved, edited, and was compared pair-wise with NCBI non-redundant nucleotide database using BLAST homology search and the highest hits were used to identify the isolates (Altschul et al. 1990). The retrieved DNA sequences were aligned with ClustalW (Thompson et al. 1994) and a phylogenetic tree was constructed by using MEGA7 software (Kumar et al. 2016). The antibacterial activity of several generally available substances (viz., mustard oil, sorbitol, white vinegar, glycerol, and olive oil) was evaluated against the isolated bacteria following agar well diffusion assay (Bauer et al. 1966). At first, 100 µl culture of the bacterial isolate was spread onto the Mueller Hinton Agar (MHA) medium, and wells (8 mm) were made by using a sterile cork borer in each culture plate. Then 50 μl of mustard oil, sorbitol, vinegar, glycerol, and olive were placed into the wells sequentially. The plates were then incubated at 37°C for 24 hrs. Then the diameter of the inhibition zone was measured at the nearest millimeter (CLSI 2006). Experiments were repeated three times. To eliminate the bacterial contaminants from date palm fruits, samples were separately submerged in tubes containing either vinegar (Entani et al. 1998) or normal saline (control), homogenized, and left for an hour. Then an aliquot from each of the tubes was streaked onto a NA plate side by side keeping a reasonable distance between them. After incubating at 37°C for 48 hrs, the plate was checked for bacterial growth.