NTU Undergraduates' research April 2014 - Biosciences | Seite 7

The Survival of E. coli in Food Products
Waqar Nadim Khan

Department of Biomedical Science, Nottingham Trent University, Clifton campus, Clifton Lane, Nottingham, NG11
8NS
Different strains of E. coli causing diseases are classified according to the type of symptoms that they initiate. E. coli
(O157:H7) strain is the most important EHEC (Enterohaemorrhagic Escherichia coli) serotype linked to foodborne
disease. A variety of food products have been associated with Enterohaemorrhagic E. coli and were used to explore
the survival of E. coli within their environment. An overnight culture was inoculated into milk, yoghurt and ground
meat (animal sources), bean sprouts (vegetables) and concentrated fruit juice. The effect of time and temperature
was also explored with the products incubated at the temperature they would usually be. Survival of E. coli within
the time period was exhibited in all the samples whether the population increased or decreased. Viable counts
through the Miles and Misra technique were used to determine the extent of survival across two incubation times
(1 hour and 24 hours). The greatest growth and thus survival occurred in meat due to its composition and
nutritional substances. This was followed by yoghurt due to its live bacteria and components and the bean sprout
samples which were past their use-by date due to pH changes.