Question

Explain how you could use PCR to determine if food like spinach is infected with E.coli or not.

Answer 1

Answer:

For detecting E.Coli in the food such as spinach we need to enrich the E.Coli because the concentrations can be low and detection by PCR would, therefore, be hard.

So, the E.Coli needs to be enriched which is a common method of bacterial isolation which helps in increasing cell count of the target micro-organism and helps in detection among other flora which may be present in the sample (e.g, Spinach).

Therefore, E. coli can be enriched with the help of E. coli (EC) broth or modified tryptic soy broth (mTSB).

Then after enriching the E.Coli (which needs about 3 - 5 hrs of time).

PCR can be performed after that. To detect the E. coli in the spinach sample via the PCR technique uidA primers can be used on the samples.

Therefore, we can find whether a food sample like Spinach is infected with E.COLi or not by first enriching the sample and then performing PCR by using uidA gene-specific primers which are quite appropriate to detect E. coli rapidly in food samples like Spinach.