Food Handlers Perception On Food Safety, Occurrence And Characterization Of Enterotoxigenic Staphylococcus Aureus Isolated From Foods Of Animal Origin In Nairobi, Kenya

ABSTRACT

Diarrheal diseases are the commonest manifestation of food poisoning, which are fatal. Knowledge, attitude and practice of food handlers influence the occurrence of food poisoning. Staphylococcus aureus is considered the third most important cause of food-borne diseases in the world after Salmonella species and C. perfringens. Antimicrobial resistance and enterotoxigenic properties of S. aureus in food of animal origin in many parts of Kenya are scanty. The aim of the study was to investigate food handlers’ perception on food safety and characterization enterotoxigenic S. aureus in foods of animal origin in Nairobi Kenya. A cross-sectional descriptive study was conducted in Nairobi and its environs, confined to meat and milk outlets. In the first stage of the study on food safety, food handlers (n=100) were interviewed and questionnaire administered to assess their knowledge, attitudes and practices (KAP). In the second phase, food samples of animal origin (n=420) were randomly purchased from different outlets. Additional 251 samples of various pork products from a meat processing plant were collected for isolation and characterization of enterotoxigenic properties of S. aureus. Colonies of S. aureus were selected from Baird-Parker medium plates for identification using the biochemical tests. Reverse Passive Latex Agglutination was used to identify enterotoxigenic strains. Gene distributions were detected by multiplex Polymerase Chain Reaction (mPCR) reaction. Their resistance to eight commonly used antibiotics was determined using Kirby-Bauer disc diffusion test. Results on Knowledge, Altitudes and Practices showed that overall scores were not significantly affected by marital status and religion of the respondents. Gender comparisons revealed that the mean KAP scores for men and women food handlers were similar. A total of 251 (37.4%) of S. aureus strains were isolated and identified. The proportions of contamination of animal products from the seller and meat processing plant were comparable. The contamination rate of the meat and meat products sample (40.7%) was significantly higher than milk and milk products (25.0%) (p=0.001). Most of the strains 187 (74.5%) produced staphylococcal enterotoxin (SE) with staphylococcal enterotoxin A (SEA) being the most frequent (90, 48.1%), followed by a combination of SEA and SEC (22, 11.8%). Most frequent gene detected by multiplex PCR was sea (61.8%). Genes see, sed, sec, and seb were observed in 33.3%, 17.5%, 15.9% and 13.9% strains, respectively. Combination genes found to occur in pairs were Sea/See (21.2%), Sea/Sed (9.8%), Sed/See (2.1%), Sea/Sec (0.7%) and Seb/Sec (0.5%). A combinations of four genes sea/sec/sed/see accounted for only 0.01%. Relatively low number (2.1%) of discrepancies between multiplex PCR and Reverse Passive Latex Agglutination (RPLA) assay particularly on SED. The results of both methods were identical concerning SEA, SEB and SEC. All of the strains showed multi drug resistance (MDR) to major classes of antibiotics tested with Penicillin G having the highest resistance level (246, 99.6%) followed by Ampicillin (230, 93.1%). The study concluded that knowledge attitude and practice performance seemed to improve along the level of education and work experience. High level of contamination of foods of animal origin by enterotoxigenic and MDR strains of S. aureus was evident. The study indicates a need for good hygiene practices in food processing, in order to minimize staphylococcal food poisoning, which poses a health risk for the consumers.