Prevalence and Antimicrobial Susceptibility of Escherichia Coli O157 Isolated From Raw Milk Marketed in Chittagong, Bangladesh

Escherichia coli is an emerging public health concern in most countries of the world. It is an important cause of food-borne human disease. The present study assessed the prevalence and determined the antibiotic resistance patterns of E. coli from raw milk marketed in Chittagong, Bangladesh. Of the raw milk marketed in Chittagong ~33(18%) of the 186 raw milk samples of it contains E. coli, indicator bacteria for any enteric pathogens. The mean viable count of total bacteria was 4.04×108 cfu/ml and the mean viable count of E. coli in the contaminated raw milk was 1.88×106 cfu/ml. E. coli from only six (18.2%) of the 33 positive samples yielded colourless colonies across the CT-SMAC, suggesting the probable presence of populations belonging to the serotype O157 and rest of the isolates 27 (81.82%) produced coloured colony on CT-SMAC considering the probable presence of populations belonging to the serotype non-O157. Growth of probable E. coli O157, as evidenced by the colourless colonies on CT-SMAC compared to coloured colonies from other bacteria. Confirmed isolates were further subjected to antimicrobial susceptibility test using the Agar disc diffusion technique. Antibiotics susceptibility profile showed that all the isolates in case of E. coli O157, penicillin (100%), tetracycline (100%), amoxicillin (83.33%) and erythromycin (83.33%) were the most resistant whereas ciprofloxacin (66.67%), gentamicin (50.0%), and streptomycin (50.0%) were the most sensitive antibiotics. In case of E.coli non-O157 susceptibility profile showed that chloramphenicol (40.74%), erythromycin (40.74%) and oxacillin (37.04%) were the most resistant whereas ciprofloxacin (70.37%), sulphamethoxazole/trimethoprim (S/T) (59.26%) and gentamycin (55.55%) were the most sensitive antibiotics. The antimicrobial resistance exhibited by E. coli O157and non-O157 strains in this study is an indication of possible antibiotic abuse

Optimization of Drying Parameters for Total Phenolic Content of Papaya Using Response Surface Methodology

An optimum condition of the drying process can minimize nutrient losses and maximize the shelf life of food products. Thus, this study is aimed at developing an optimized system for the process conditions to determine the total phenolic content (TPC) of oven-dried papaya slices. The response surface method and central composite design were used to design the experiment, and it was found that the drying conditions had a significant impact on the total phenolic content of papaya slices. TPC was determined in relation to their interactions with the independent variables that include time, temperature, sample thickness, and stage of ripeness. The optimum drying conditions are those with the maximum content of TPC. In order to fit the experimental data, a quadratic polynomial model is created for the output variable, and an analysis of variance is carried out to determine whether or not the model is compatible to determine the optimal drying conditions. Time (10 h), temperature (62.02°C), thickness (9.75 mm) and stages (ripe) were found to be the optimal drying conditions. It was found that temperature had more effect on the amount of TPC than other factors. The numerical findings showed a good agreement with experimental data, with R2=0.9237. It is hoped that the findings will make a contribution to the process of drying food

Drying methods effect on bioactive compounds, phenolic profile, and antioxidant capacity of mango powder

The effects of various drying methods (spray drying, cabinet drying, vacuum drying, tunnel drying, rotary oven drying, and gas oven drying) on the phenolic profile, bioactive compounds, and antioxidant capacity of mango powder have been considered with the aim of discover the effective drying technique. To identify and quantify the phenolic profile, the Folin-Ciocalteu method was used, while 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging studies were utilized to elucidate the antioxidant capacity. Results showed that total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC) and total carotenoid content (TCC) showed substantial variations (p < 0.05) between different drying methods, and the antioxidant properties were influenced to different degrees by drying methods. The antioxidant capacity of dried mango powder is strongly correlated with phenolic compounds (polyphenol, flavonoids, and anthocyanin). Caffeic acid was predominant among the 16 phenolics in mango powder. Flavonoids had higher retention factors (RF) than phenolic acids. Finally, our findings indicate that both cabinet drying and vacuum drying are appropriate for mango powder production. However, taking into account both economic viability and phenolic compound quality, cabinet drying would be the supreme choice for the outturn of mango powder as antioxidant-rich flavor enhancers

Insecticide-treated bed nets in rural Bangladesh: their potential role in the visceral leishmaniasis elimination programme

Objective To analyse the feasibility, acceptability and effectiveness of insecticide-treated bed nets with slow-release insecticides (KO Tab 123) as an option for kala-azar vector management in Bangladesh. Methods Intervention study involving an insecticide dipping programme through village health workers supervised by public health officers covering 6967 households in Mymensingh and 8287 in Rajshahi district. In a subsample of households, sandfly densities at baseline, 1, 12 and 18 months were measured with CDC light traps both in intervention and control areas. Bioassays were performed for determining the bioavailability of the insecticide and tests of chemical residues in the treated bed nets were undertaken. Satisfaction surveys and direct observation of use of treated bed net use were conducted. Results The dipping programme was feasible with the help of communities and public health staff, was well accepted, reached a coverage of 98.2% and 96.2% in the two study sites within 4 weeks and was effective in terms of a significant reduction in sandfly densities (approximately 60%) for a period of 18 months. Bioassay results were satisfactory (>80% sandfly mortality) and the average chemical content of the treated bed nets was sufficient for killing sand flies at the end of the observation period. Conclusion Bed nets treated with slow-release insecticides can be an important complementary measure for sandfly control in the visceral leishmaniasis elimination programm