Question

Discuss one error encountered with the turbidimetric method and it’s effect on your final result in the expeiment Standard Plate count and Turbidimetric Methods to Enumerate the numbers of Microorganisms in a population

Answer 1

Turbidometry is one of the most commonly used preliminary method to perform count of microbial load in a given sample. According to the this technique, a ray of light is passed through a sample of unknown concentration and the absorbance as well as transmittance of the light coming out of the sample is recorded. The extent of transmittance then is used to make a calculation for the total microbial load in the sample, as more is the microbial load, less is the transmittance. Thus while the light travels through the sample, the turbidity of the sample is used to calculate the absorbance or transmittance.

However, some errors can be encountered with these methods as enlisted below:

1. Low levels of bacterial load cannot be measured using this method
2. Very high concentrations of microbial load too cannot be measured using this method
3. Non-homogenous samples generally give false positive/negatives
4. Human errors, such as cell counting, weighing, diluting etc can also account for false positive/negatives as well as deviations in the measurements.

Thus, trubidometry must be performed under expert supervision with precision and accuracy. It is always advisable to validate the results with more optimized methods.