Bacteria associated with street vended foods: implications to food quality and safety

Street vended foods were analysed for the bacterial load and the presence of pathogenic and/or potentially pathogenic bacteria. The foods were collected randomly from ambulatory and stationary vendors and analysed individually and then categorized as meats, salads and carbohydrates. The microbial analysis indicated that the foods that were served by ambulatory vendors had higher microbial load than those that were served from stationary ones. The salads were also found to contain high microbial load than other food types. The food was also contaminated with coliforms of fecal origin. E. coli was isolated from some food and it occurred in low counts as the highest count was 2.0 log10 CFU/g. The pathogens isolated from the foods were B. cereus, Listeria species, and S. aureus. No Salmonella or Enterococci were recovered from the food. Generally, the microbiology of the street foods was of acceptable quality, with the exception of the salads, and the results better than that of foods reported in other studies. This was despite the fact that most of the vendors operated under seemingly unsanitary conditions.Keywords: Street foods, safety, aerobic plate count, fecal coliforms, pathogens, ambulatory, station

Incidence Of Indicator Organisma, Opportunistic And Pathogenic Bacteria In Fish

Fish is an excellent source of high quality protein; however, it is susceptible to microbial spoilage. Fish carries high microbial load on the surface of the skin, in the intestine and in the gills. In Botswana, fishermen catch fish and sell their products in the open market. The microbiological quality and safety of these street vended fish have always been contentious. Therefore, a study on fish sold in Gaborone, Botswana was conducted from July 2006 to January 2007. Tilapia from the supermarkets and tilapia and catfish from street vendors were analyzed for the microbial load, presence of indicator microorganisms, opportunistic and pathogenic bacteria using conventional microbiological methods. Though coliforms were found in 84% of fish from the street vendors, only 16% of the fish had coliforms above the acceptable limits (3 log10 CFU/g). No Escherichia coli were isolated. Bacteria which are associated with plants, animals and soils but are normally classified as coliforms because of their biochemical reactions to sugars such as Citrobacter species, Klebsiella species including the enteropathogen Salmonella species were isolated. Fresh water or tap water is not available where vendors degut the fish. Hence, they carry water in containers to the point of sale sites and use it repeatedly. The unsanitary water (8.7 log10 CFU/ml of bacteria) used during the gutting of tilapia on the streets influenced the microbial levels in the fish, which were 6.0 log10 CFU/g compared to the 3.90 log10 CFU/g of ungutted whole tilapia from the same sale points. Frozen tilapia from supermarkets also had high bacterial counts (4.8 log10 CFU/g). Staphylococcus species were isolated frequently in all fish analyzed. Salmonella arizonae, Salmonella paratyphi (22-40%) was only isolated in street vended fish. Other bacterial isolates from fish included Citrobacter brackii, Citrobacter freundii, Enterobacter sakazakii, Enterobacter cloacae, Vibrio cholorae, Proteus mirabilis, Proteus vulgaris, Klebsiella pneumoniae and Aeromonas hydrophila. The presence of diverse enteric bacteria indicated the degree of cross contamination from the handlers. Their presence represents a potential hazard to humans, especially the immuno-compromised consumers such as cases of HIV/AIDS. Stringent regulations on registration of fishermen, traders, education and mandatory observance of sanitation at trading points and use of ice have to be enforced to ensure safety of fish consumption

PREVALENCE OF ROTAVIRUS, ADENOVIRUS AND ASTROVIRUS INFECTION IN YOUNG CHILDREN WITH GASTROENTERITIS IN GABORONE, BOTSWANA

ABSTRACTObjective: To determine the prevalence of three enteric viruses, namely rotavirus,adenovirus and astrovirus, as agents of diarrhoea in and around Gaborone, Botswana.Design: The sample were categorised into four groups according to the age of the patient:0-3 months, 4-6 months, 7-12 months and 25-60 months. Total monthly samples acrossage groups formed basis for calcultating seasonal prevalence of rotavirus infection.Setting: Stool samples were collected from three medical laboratories in Gaborone andone in the town of Mochudi. These were collected from children under the age of fiveyears with gastroenteritis.Subjects: Stool samples were collected between March 2001 and February 2002 from346 children less than five years of age suffering from gastroenteritis. These sampleshad been sent to medical laboratories for microbiological examination.Methods: The samples were screened for rotavirus (RV), adenovirus (Ad) and astrovirus(AsV) antigens using commercially available ELISA kits. The Ad positive samples werefurther analysed by commercially available group specific Ad type 40/41 EnzymeImmuno Assays (EIA).Results: Shedding of RV was detected in 9.2%, Ad in 7.8% and AsV in 2.7% of thesamples analysed. The enteric Ad (types 40 and 41) were detected in 2% of the samplesand the remaining 5.8% of Ad positive samples were non-enteric Ad. An increase ofRV was noted in the autumn-winter season but no seasonal pattern was observed inAd shedding. Seasonal prevalence of AsV could not be determined. The average ageof children infected with these agents was less than one year.Conclusion: The incidence of rotavirus infection amongst children in Botswana appearsto be relatively low. The prevalence rate of adenovirus and astrovirus is similar to otherstudies in parts of Southern Africa. However, continued enteric virus surveillance andepidemiology amongst this group is required