NTU Undergraduates' research April 2014 - Biosciences | Page 61

Determining the Sensitivity and Specificity of Culture-Based Methods and PCR
for the Detection of Salmonella typhimurim as a Surface Based Contaminant
Lauren Plant
Food contact surfaces have the potential to transmit food borne pathogens through crosscontamination. Therefore, it is important to be able to rapidly detect the pathogenic
microorganism to minimise the risk of contaminating foods, which have the potential to result in
an outbreak of food borne gastroenteritis. The aim of this research project is to determine to what
degree culture based methods and PCR are sensitive and specific in terms of detecting Salmonella
typhimurium, a potential surface-based contaminant. Compare the results, and evaluate and
reflect on the results and the research carried out. Serial dilutions of S. typhimurium were
prepared to determine the level of sensitivity of both methods in detecting the bacterial organism,
and Escherichia coli K12 was used to ensure the specificity of the HilA primers. For the culturebased method, the spread plate technique was used for the enumeration of S. typhimurium in
order to determine the level of sensitivity of this method.