Month: March 2011

Research Blog: Predictive Microbiology (Vedish Bhatoolaul)

Thoughts and Analysis

This blog post is intended to be more of a collection of my personal thoughts, opinions and questions on the research area I am currently working on rather than a microbiologically correct treatise on the subject.

As a theoretical physicist, my microbiological insight will be rather limited and sparing at best; hence the conjectural and interrogative tone of this account.

Please note that this account is chronological and is being continuously updated. (Posts at the end of the account will be most up-to-date with findings compared to earlier ones.)

As you will eventually gather by reading my posts, I am working on building an Individual-based Model to try and predict bacterial growth and inactivation.

Potato density changes with age – by Karim Bahsoon

Potato density vs Age (expiration date of potatoes 1st March 2011)

As discussed we have been measuring the density change of the potato over a number of days. The potato was left out at room temperature and the density measurements were carried out using the same method as before (filling measuring jug with water to assess volume/mass change).

DATE MASS (g) VOLUME DISPLACED (ml) DAYS AFTER EXPIRY DENSITY (g/ml) 24/02/11 142 130 -5 1.092307692 25/02/11 142 130 -4 1.092307692 28/02/11 140 129 -1 1.085271318 01/03/11 140 129 0 1.085271318 03/03/11 139 129 2 1.07751938 07/03/11 138 128 6 1.078125

The density change has been fairly minimal, and the precision of the scale (accurate to 1 gram) has perhaps hindered the experiment somewhat.

Starch concentration measurement in potatoes – by Jason Chang

New density measurements and Calibration

As advised from the last meeting we placed the measuring jug on an electronic scale, reset the scale to zero and filled it with 400g worth of water. We found that there was a small error in the jug which produced the systematic errors in our previous measurements. We marked the real 400ml mark with a pen and took new volume and weight measurements. I also skinned two of the potatoes to check the removal of skin didn’t significantly change the density (The rows highlighted in the same colour correspond to the same potato). Below is a table of results of potatoes with the skin on: