So so tired at the end of Week 2… (Day 18)

testing-milk-fat-content

Ok so its Friday so thats probably an excuse for me being so tired today, I also got stuck into Anatomy revision last night as I really am pushing myself for the A now. Its the end of my second week of lectures in Vet School and it has finally sunk in that I am really here and that it’s not just a holiday! I really am looking forward to getting some sleep this weekend, though realise I have a ton of stuff to catch up with fundraising for next semester, finishing some painting in my room and also got to get my residency permit sorted so that I can get a bank account here.

Anyways this mornings lecture was Genetics, this is definately somewhere I am going have to do my own additional reading. I lack the biology and chemistry A-Levels that many have so have to really get back to basic to understand the more advanced theories. This is also going onto my weekend reading list.

This was followed by the Milk Hygiene practical which this week was very interesting. Basically (in Slovakia at least) milk has to go through several different quality controls before it can enter the human foodchain. The basic tests for this look at fat content and protein content of the milk, this also helps ensure that milk has not been watered down. The first test for fat content uses a really strong concentration of Sulphuric Acid to seperate the fat molecules. Cue the first appearance of Health and Safety here with faceshields and massive aprons!!! Anyways the method that we used was the Gerber method which is used worldwide as its a very simple and extremely rapid way to determine the volume of the fat in the sample. It uses a special tube called a butyrometer in which the sulphuric acid is mixed with the milk sample and osoamyl alcohol before it is placed in a centrifuge and the result read by moving the stopper on the tube in and out.

testing-milk-fat-content
4 different milk samples in 4 butyrometers to determine the volume of fat contained in the sample

Yes that tarry looking black substance is in fact milk… The thin tube on the top actually contains the scale and the tube on the left has the most fat and the tube on the right the least fat content. One of the basic requirements for dairys is that the milk produced contains at least 3.5% fat. The other classifications of skinned and semi-skinned have their own margins which the reading has to fall between.

The next test of the day was for protein content and was carried out using Formol titration with the chemicals below (love how the only understandable thing on the bottles are the labels of doom!) and sodium hydroxide from a burette.

Chemicals with the labels of doomThis method relies on the neutralisation of the milk by adding sodium hydroxide and doing a calculation based on the quantity of sodium hydroxide actually used. Its actually pretty a pretty cool example of chemistry at work as sodium hydroxide is a clear liquid yet when added to milk turns a bright pink.

Adding sodium hydroxide to milk turns it pink
Adding the sodium hydroxide to the milk turned it pink

Pretty cool or what? The next practical of the day was for genetics where we used PCR to look at DNA, I will be doing a detailed post on this later on so will not include too many details here. Basically PCR allows for the rapid duplication of DNA and then the comparision of this DNA. By the end of this I was exhausted, vet school is definately tough and my weekend is going be very busy!

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