Milk testing - The conclusion.

In my previous post I had brought to the attention of mess council and the hostelers possibility of presence of formaldehyde/formalin in the milk sample obtained from the hostel. However, recent test done by the council members and a government accredited laboratory has confirmed the absence of any trace of formalin in the samples. I hereby restate the tests and compare the results obtained from tests done by my team and that from the council members.

Test procedure:

 Take 10 ml of milk in a tests tube and add 5 ml of con sulphuric acid from the sides of the wall without shaking. If a violet or blue ring appears at the intersection of two layers then it shows presence of formalin. 

Test results:

Result for test performed by my team

Close up of the result for test performed by my team

It is observed from the above pictures that there is a distinct brown coloration of the sample with the addition of con. Sulphuric acid. It should be noted that I did not observe any violet/blue coloration as a test result as proposed in [1].  

The council team has repeated the test procedure stated above on two milk samples of the same brand. Formalin is intentionally introduced into one sample(sample 1) while the other sample is kept free of any intentional addition of the banned adulterant(sample 2). Intentional addition of formalin was performed to reconfirm whether violet/blue coloration really happens when con. Sulphuric acid reacts with formalin as mentioned in [1].

The test tube on the right shows the result of test performed on sample 2.  The distinct brown coloration as observed in my test is noticed in this case also.
However, the result in the left tube, which pertains to sample 1(which has intentional addition of formalin) shows a distinct violet/blue coloration instead of a brown one. Referring to the test procedure, it can be concluded that such a violet/blue coloration is the real indication of formalin as opposed to the brown coloration observed in my tests or that performed on sample 2.

 Hence, it is conclusively confirmed from the above observations that the milk brand does not contain any presence of formalin in it. 

I would like to state that misinterpretation of the results from my side has lead to misleading conclusions in my previous report regarding the presence of formalin in the milk sample. I would like to apologize for the same. 

In this regard, I would also like to thank the council members for taking active measures for ascertaining the scientific validity of my claim. I hope that council will hereby take active interest in extending such test to other food items served in the mess for the common good of all. 

References:
1. http://fda.up.nic.in/household_tests.htm