A cross sectional study was conducted at Wolkite University cafeteria, South Ethiopia from December to February 2017 from 170 food handlers. At present, the cafeteria has 340 food handling personnel serving for about 11,000 students. All food handlers from the University food handling establishment were included and then proportional allocation was considered to select 170 food handlers from each section. Food handlers who had taken anti-helminthics within the three weeks prior to the study and newly recruited were excluded.
Sample size was determined after a single size population proportion formula taking a proportion of 6.9% Salmonella species prevalence in Arbaminch University cafeteria(Mohammed), Zα/2=1.96, confidence level of 95%, and margin of error = 0.04. The sample size became 156 and the final sample size after adding 10% non-response rate was 170.
Data collection and processing
Personal data, hygienic profile, knowledge and attitude assessments were handled by structured questionnaire adopted from similar survey and literatures.
Ova/parasite detection: A loop full of stool sample was collected from each food handler and examined following direct wet mount preparations in normal saline, iodine solution and formol-ether concentration sedimentation techniques as per the standards. The parasites identified in any one of the three techniques from a single specimen will be reported as positive .
Culturing of Salmonella and Shigella spp.
Stool specimens were pre-enriched with Selenite F broth and inoculated to Xylose Lysine Deoxycholate (XLD) by incubating at 37°C for 24 hours for isolation of Shigella and Salmonella isolates. Colony characteristics and biochemical tests were applied to differentiate enetero pathogens, glucose and lactose fermentation, hydrogen sulfide production, Kliger iron agar, indole, Simon’s citrate agar, lysine iron agar, urea, and motility .To differentiate from other enterobacterceae and as a confirmatory test we use API-20E (Biomerieux, France).
Antibiotic susceptibility was performed by Kirby-Bauer disc diffusion on Muller-Hinton agar using Norfloxacillin (10μg), Gentamicin (10μg), Ceftriaxone (30μg), Ciprofloxacin (5μg), Tetracycline (30μg), Chloramphenicol (30µg) and Trimethoprim-Sulphamethoxazole (25μg). The reading and interpretation of the results as sensitive, intermediate, and resistant were conducted in reference to CLSI, 2015 .
Quality Control: Standard Operating Procedures (SOPs) were strictly followed during laboratory specimen’s collection, processing and culturing. American type culture collection bacterial reference strain of Escherichia coli ATCC25922 was used as a quality control for antibiotic susceptibility testing.
Data analysis: The data were edited, coded, and entered into SPSS for Windows version 20.0. Descriptive statistics were used to determine frequency, prevalence, and percentage. The relationship between variables was computed using chi-square (with value of 0.05 and 95% confidence interval).