Hygiene Knowledge, Practices and Microbial Safety of Mixed Vegetable Salads Sold in the Streets of Pipeline Ward, Nairobi County, Kenya

Abstract

Street foods are those sold outside in the public place without a permanent structure and are most often ready to eat. However, ready-to-eat foods are a source of contamination and can transmit foodborne diseases. This study assessed hygienic knowledge and practices, status of microbiological contamination of mixed vegetable salads sold in pipeline ward of Nairobi County in Kenya and to determine the exposure to pathogenic microorganisms through consumption. Questionnaires and personal observations were the two main instruments used for gathering the data. Vegetable salad samples were collected from the vendors and were transported to the laboratory and analyzed for Staphylococcus aureus, Escherichia coli, Salmonella SPP following recommended standard procedures. Consumption and contamination were then combined to estimate exposure of consumers. The average bacterial intake and the 95th percentile (P95) intake levels estimations were obtained using Monte Carlo simulation models. Out of …venders, majority (60%) of the respondents were males and in the age category of 26-35 (53%) and most of them had up to secondary level of education (73%). Majority of the vendors (59%) had been trained on food handling practices and therefore had good knowledge of food hygiene, and practiced good hygiene. The results indicate that a few (percent?) of the respondents did not practice food handling hygienic practices predisposing salads to contamination. Majority of the consumers (64%) had estimated body weight above 60 kgs and heights ranging from 1.7-2.0 meters. About 91 % of respondents purchased mixed salads on weekly basis and consumed it directly without additives. Majority (67 %) of respondents reported an increase in consumption trend, which was linked to increased number of vendors along the streets. The salad consumption was characterized by triangular distribution and ranged from 0.53 to 4.01 g/kgbwt/day with an average consumption of 1.88 g/kgbwt/day. Staphylococcus aureus was present in 98 % of the samples while Escherichia coli tested positive for about 73 % of the samples. Only 18 % of the analyzed samples were xiii contaminated with Salmonella spp. The S. aureus concentrations ranged between 2.01 log CFU/g and 3.77 log CFU/g while that of E. coli ranged between 2.63 log CFU/g to 3.49 log CFU/g. The average intake of Staphylococcus aureus was 5.83-log cfu/kgbwt/day, E.coli was 5.50 log cfu/kgbwt/day while Salmonella spp was 0.19 log cfu/kgbwt/day. The 95th percentile (P95) intake of Staphylococcus aureus was 10.92 log cfu/kgbwt/day, E.coli was 10.15 log cfu/kgbwt/day while Salmonella spp was 0.58 log cfu/kgbwt/day. All the vegetable salads sampled from different zones, in Pipeline Nairobi had a high contamination levels. The high contamination levels of these pathogens could be as a results poor handling of the vegetables right from the farm up to consumption point. This calls for awareness of the possible hazardous effect of consuming street sold vegetable salads. It is therefore important that policies that regulate microbial quality of street vended foods are put in place and are practiced by vendors. Street food vendors and consumers should be cognizant of both personal and environmental hygiene since street foods are literally prepared and served on the street with the preparation area exposed to the natural elements should be taken care