I want to measure the OD of 5 anoxic bacteria culture which have different substrate. I do this for obtaining the growth curve. I mesured the OD but I had some wrong results so I freeze the first 3 samples and I measured by spectophotomer again and the values were what I was expecting. I did the same for another 2 days.
Now I thaw out the samples and when I measure the OD of all and I have absurde results.
What I did wrong or what I could do from now on?