Occurrence and molecular characterization of salmonella in ready-to-eat salads sold in Ado-Ekiti, Nigeria

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Research Paper 01/02/2020
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Occurrence and molecular characterization of salmonella in ready-to-eat salads sold in Ado-Ekiti, Nigeria

MA. Oyinloye, TA. Ogunnusi, G. Ejimofor
Int. J. Micro. Myco.11( 2), 7-18, February 2020.
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Vegetable salads are main dish of daily meals served in homes, schools and restaurants. However, it has been found to be associated with the outbreaks of foodborne diseases in many countries around the world. This study investigated the microbiological quality of vegetable salads sold in Ado-Ekiti, Nigeria, particularly the presence of Salmonella spp. Samples examined included different types of fresh ready-to-eat (RTE) vegetable salads. A total of 170 vegetable salad samples were collected from fast food outlets and street vendors. Microbiological examinations included total viable count and total coliform count using pour plate technique, and isolation of Salmonella spp. using SalmonellaShigella agar. DNA extraction, PCR and 16S rRNA sequencing were performed to determine the Salmonella spp. isolated. A total of 8 (4.7%) and 9 (5.2%) of the salads were below standard guidelines for total viable count and total coliform count respectively. Salmonella was isolated from 66 (38.8%) samples. There was no statistical significant correlation (P >0.05) between all sample sources and the different types. Salmonella spp. was resistant to cephalosporins and β-lactamase inhibitors, producing five different antibiotic resistance profiles. Representative isolates were homologous to sequences on NCBI database revealing three subspecies of Salmonella enterica. This survey showed that RTE vegetable salads consumed from fast food outlets and street vendors in Ado Ekiti, Nigeria are of public health concern, hence the need for government health agencies to monitor and regulate their production.


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