ABSTRACT
Drying is one of the oldest methods of preserving food. The extended shelf life of dried foods have led to consumer perception that such foods are not of concern from a microbiological perspective. However the number of incidences relating to outbreaks caused by the presence of food-borne pathogens in low water activity foods have increased. The aim of this study was to determine the antimicrobial susceptibility pattern and the presence of virulence screening in bacteria isolated from dried foods. Dried food samples comprising of powdered guinea corn and maize, Soya bean powder, grinded cray fish and powdered chocoflavour were obtained from local retail outlets in Benin City. The pH of the samples were determined using an electrode pH meter while the moisture contents were determined by the method of AOAC. All samples were serially diluted and inoculated on Nutrient agar and Violet red bile glucose agar. Pure cultures were obtained and identified based on cultural, morphological and biochemical characteristics. Antibiotic susceptibility pattern of the isolates was determined using the disc diffusion method and isolates were screened phenotypically for the presence of virulence factors based on haemolytic activity on blood agar and extracellular protease (gelatinase) production. Bacteria counts in this study ranged from 0.13 ± 0.06 – 4.70 ± 0.10cfu/g and 0.35 ± 0.02 – 3.01 ± 0.02cfu/g for total heterotrophic bacterial count and enterobacteriace count respectively. Ten isolates were obtained in this study. They include; Proteus mirabilis, Yersinia sp, Enterobacter sp, Streptococcus sp, Klebsiella pneumonia, Streptococcus sp, Salomonella enterica, Klebsiella pneumonia, Shigella sonnei and Enterobacter aerogenes. Results for the pH of the samples ranged from 5.47 ± 0.12 – 6.60 ± 0.01 while the moisture content ranged from 10.29 – 0.01%. Results of the antibiotic susceptibility test revealed that the antibiotic susceptibility profiles of various bacterial strains varied significantly. Streptococcus sp. was resistant to chloramphenicol, sparfloxacin, amoxicillin, and augmentin but susceptible to septrin, ciprofloxacin, gentamicin, and pefloxacin. Proteus mirabilis exhibited resistance to septrin, chloramphenicol, sparfloxacin, amoxicillin, augmentin, and gentamicin, while being susceptible to ciprofloxacin and pefloxacin. Yersinia sp. displayed resistance to septrin, chloramphenicol, sparfloxacin, amoxicillin, gentamicin, and pefloxacin but was susceptible to ciprofloxacin and augmentin. Enterobacter sp. showed resistance to chloramphenicol, ciprofloxacin, augmentin, and gentamicin but susceptibility to septrin, sparfloxacin, amoxicillin, and pefloxacin. Salmonella enterica and another strain of Streptococcus sp. were susceptible to a wide range of antibiotics. Klebsiella pneumonia was susceptible to septrin, ciprofloxacin, and pefloxacin but resistant to several others. Shigella sonnei was susceptible to septrin, ciprofloxacin, amoxicillin, and gentamicin but resistant to chloramphenicol, septrin, augmentin, and pefloxacin. Another strain of Klebsiella pneumonia was only susceptible to ciprofloxacin, while Enterobacter aerogenes showed susceptibility to chloramphenicol, ciprofloxacin, and augmentin but resistance to septrin, sparfloxacin, amoxicillin, gentamicin, and pefloxacin. While results of the haemolysin test showed that All isolates obtained from the samples produced β hemolysin except Streptococcus sp. which produced α hemolysin. From the gelatinase production test, most (7/10) of the isolates had the ability to form biofilm. The study highlights concerns about the safety of dried foods, with bacterial counts and antibiotic resistance in some isolates. It emphasizes the need for improved quality control, hygiene practices, and consumer education in handling dried foods and this can be done by implementing strict quality control measures, educating consumers on proper handling, maintaining good hygiene practices, and continuous research for safety assurance.
